From 81702e5c252dbe483e26f2e6a70ad2a39aca5b01 Mon Sep 17 00:00:00 2001
From: Martin Goik <goik@hdm-stuttgart.de>
Date: Fri, 12 Jan 2018 14:56:50 +0100
Subject: [PATCH] Deleting Car jump exercises, new String mask exercise
---
Doc/Common/snippets.xml | 10 +
Doc/Sd1/Ref/Fig/carSlope.fig | 72 --
Doc/Sd1/Ref/Fig/velocityDecompose.fig | 40 -
Doc/Sd1/coreClasses.xml | 467 ++++++---
Doc/Sd1/objectsClasses.xml | 959 +++++-------------
P/Sd1/CarJump/V1/.gitignore | 4 -
P/Sd1/CarJump/V1/pom.xml | 48 -
.../hdm_stuttgart/mi/sd1/carjump/Driver.java | 19 -
.../mi/sd1/carjump/model/CarJump.java | 40 -
.../CarJump/V1/src/main/resources/log4j2.xml | 21 -
P/Sd1/CarJump/V2/.gitignore | 4 -
P/Sd1/CarJump/V2/pom.xml | 48 -
.../hdm_stuttgart/mi/sd1/carjump/Driver.java | 19 -
.../mi/sd1/carjump/model/CarJump.java | 74 --
.../CarJump/V2/src/main/resources/log4j2.xml | 21 -
.../mi/sd1/carjump/ModelTest.java | 22 -
P/Sd1/CarJump/V5/.gitignore | 4 -
P/Sd1/CarJump/V5/pom.xml | 48 -
.../hdm_stuttgart/mi/sd1/carjump/Driver.java | 19 -
.../mi/sd1/carjump/model/CarJump.java | 110 --
.../mi/sd1/carjump/ModelTest.java | 22 -
P/Sd1/CoreClasses/StringMask/.gitignore | 54 +
P/Sd1/CoreClasses/StringMask/pom.xml | 80 ++
.../java/de/hdm_stuttgart/mi/sd1/Mask.java | 55 +
.../StringMask}/src/main/resources/log4j2.xml | 2 +-
.../de/hdm_stuttgart/mi/sd1/MaskTest.java | 40 +
P/pom.xml | 1 +
27 files changed, 785 insertions(+), 1518 deletions(-)
delete mode 100644 Doc/Sd1/Ref/Fig/carSlope.fig
delete mode 100644 Doc/Sd1/Ref/Fig/velocityDecompose.fig
delete mode 100644 P/Sd1/CarJump/V1/.gitignore
delete mode 100644 P/Sd1/CarJump/V1/pom.xml
delete mode 100644 P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
delete mode 100644 P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
delete mode 100644 P/Sd1/CarJump/V1/src/main/resources/log4j2.xml
delete mode 100644 P/Sd1/CarJump/V2/.gitignore
delete mode 100644 P/Sd1/CarJump/V2/pom.xml
delete mode 100644 P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
delete mode 100644 P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
delete mode 100644 P/Sd1/CarJump/V2/src/main/resources/log4j2.xml
delete mode 100644 P/Sd1/CarJump/V2/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
delete mode 100644 P/Sd1/CarJump/V5/.gitignore
delete mode 100644 P/Sd1/CarJump/V5/pom.xml
delete mode 100644 P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
delete mode 100644 P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
delete mode 100644 P/Sd1/CarJump/V5/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
create mode 100644 P/Sd1/CoreClasses/StringMask/.gitignore
create mode 100644 P/Sd1/CoreClasses/StringMask/pom.xml
create mode 100644 P/Sd1/CoreClasses/StringMask/src/main/java/de/hdm_stuttgart/mi/sd1/Mask.java
rename P/Sd1/{CarJump/V5 => CoreClasses/StringMask}/src/main/resources/log4j2.xml (89%)
create mode 100644 P/Sd1/CoreClasses/StringMask/src/test/java/de/hdm_stuttgart/mi/sd1/MaskTest.java
diff --git a/Doc/Common/snippets.xml b/Doc/Common/snippets.xml
index e7b0269f0..6359febed 100644
--- a/Doc/Common/snippets.xml
+++ b/Doc/Common/snippets.xml
@@ -79,6 +79,16 @@
</informaltable>
</glossdef>
</glossentry>
+
+ <glossentry>
+ <glossterm>Annotation</glossterm>
+
+ <glossdef>
+ <annotation role="make">
+ <para role="eclipse">Sd1/Filepath</para>
+ </annotation>
+ </glossdef>
+ </glossentry>
</glosslist>
<qandaset defaultlabel="qanda" xml:id="qanda_">
diff --git a/Doc/Sd1/Ref/Fig/carSlope.fig b/Doc/Sd1/Ref/Fig/carSlope.fig
deleted file mode 100644
index ad2d90c82..000000000
--- a/Doc/Sd1/Ref/Fig/carSlope.fig
+++ /dev/null
@@ -1,72 +0,0 @@
-#FIG 3.2 Produced by xfig version 3.2.5c
-Landscape
-Center
-Metric
-A4
-100.00
-Single
--2
-1200 2
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 492.188 5723.438 450 4950 990 5130 1215 5445
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 2072.812 5526.562 2115 6300 1575 6120 1350 5805
-5 1 2 1 0 7 50 -1 -1 3.000 0 0 0 0 3416.500 7120.178 2912 6102 3434 5984 3921 6102
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 2688.506 6264.902 2909 6110 2951 6204 2954 6311
-5 1 0 1 0 7 50 -1 -1 4.000 0 1 0 0 4132.494 6270.902 3912 6116 3870 6210 3867 6317
-5 1 0 1 0 7 50 -1 -1 0.000 0 0 1 0 3487.500 5557.500 3465 6615 3060 6525 2655 6210
- 2 1 1.00 60.00 120.00
-6 231 4805 520 4940
-6 250 4863 366 4940
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 308.500 4920.500 270 4921 308 4882 347 4921
-1 3 0 1 0 7 50 -1 -1 4.000 1 0.0000 308 4921 19 19 308 4921 308 4940
--6
-6 404 4863 520 4940
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 462.500 4920.500 424 4921 462 4882 501 4921
-1 3 0 1 0 7 50 -1 -1 4.000 1 0.0000 462 4921 19 19 462 4921 462 4940
--6
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 347 4921 424 4921
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 4
- 270 4921 231 4921 231 4863 308 4863
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 7
- 308 4863 327 4805 404 4805 462 4863 520 4863 520 4921
- 501 4921
--6
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 1215 5445 1350 5805
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 1935 6300 450 6300
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 1 1 2
- 2 1 1.00 60.00 120.00
- 2 1 1.00 60.00 120.00
- 495 4905 495 6345
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 270 4950 450 4950
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 3
- 2113 6302 2385 6302 2912 6102
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 2430 6308 4403 6305
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 2914 6094 2239 6094
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 1 0 2
- 2 1 1.00 60.00 120.00
- 2340 5741 2340 6101
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 1 0 2
- 2 1 1.00 60.00 120.00
- 2340 6685 2340 6280
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 2925 6120 2925 5445
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 3915 6120 3915 5445
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 1 1 2
- 2 1 1.00 60.00 120.00
- 2 1 1.00 60.00 120.00
- 2925 5490 3915 5490
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 3
- 4731 6302 4449 6301 3922 6101
-4 0 0 50 -1 0 12 0.0000 6 180 525 540 5670 $h_1$\001
-4 0 0 50 -1 0 12 0.0000 6 180 525 2205 6255 $h_2$\001
-4 0 0 50 -1 0 12 0.0000 6 165 315 3240 5445 $d$\001
-4 0 0 50 -1 0 12 0.0000 6 195 720 3960 6300 $\\alpha$\001
-4 0 0 50 -1 0 12 0.0000 6 195 720 2790 6300 $\\alpha$\001
-4 0 0 50 -1 0 12 0.0000 4 180 435 3510 6660 slope\001
-4 0 0 50 -1 0 12 0.0000 4 135 1065 -630 6345 Ground level\001
diff --git a/Doc/Sd1/Ref/Fig/velocityDecompose.fig b/Doc/Sd1/Ref/Fig/velocityDecompose.fig
deleted file mode 100644
index 1ad72443e..000000000
--- a/Doc/Sd1/Ref/Fig/velocityDecompose.fig
+++ /dev/null
@@ -1,40 +0,0 @@
-#FIG 3.2 Produced by xfig version 3.2.5c
-Landscape
-Center
-Metric
-A4
-100.00
-Single
--2
-1200 2
-5 1 2 1 0 7 50 -1 -1 3.000 0 0 0 0 3416.500 7120.178 2912 6102 3434 5984 3921 6102
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 2688.506 6264.902 2909 6110 2951 6204 2954 6311
-6 2070 6120 2385 6300
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 2307.500 6270.500 2269 6271 2307 6232 2346 6271
-5 1 0 1 0 7 50 -1 -1 4.000 0 0 0 0 2153.500 6270.500 2115 6271 2153 6232 2192 6271
-1 3 0 1 0 7 50 -1 -1 4.000 1 0.0000 2153 6271 19 19 2153 6271 2153 6290
-1 3 0 1 0 7 50 -1 -1 4.000 1 0.0000 2307 6271 19 19 2307 6271 2307 6290
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 2192 6271 2269 6271
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 4
- 2115 6271 2076 6271 2076 6213 2153 6213
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 7
- 2153 6213 2172 6155 2249 6155 2307 6213 2365 6213 2365 6271
- 2346 6271
--6
-2 1 0 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 3
- 2113 6302 2385 6302 2912 6102
-2 1 1 1 0 7 50 -1 -1 4.000 0 0 -1 0 0 2
- 2430 6308 4403 6305
-2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 1 0 2
- 2 1 1.00 60.00 120.00
- 2925 6075 4365 5580
-2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 1 0 2
- 2 1 1.00 60.00 120.00
- 2925 6075 4320 6075
-2 1 0 1 0 7 50 -1 -1 0.000 0 0 -1 1 0 2
- 2 1 1.00 60.00 120.00
- 4320 6075 4320 5580
-4 0 0 50 -1 0 12 0.0000 6 195 720 2790 6300 $\\alpha$\001
-4 0 0 50 -1 0 12 0.0000 6 180 525 3690 6255 $v_x$\001
-4 0 0 50 -1 0 12 0.0000 6 195 525 4410 5895 $v_y$\001
diff --git a/Doc/Sd1/coreClasses.xml b/Doc/Sd1/coreClasses.xml
index a6192f534..c3e9db4af 100644
--- a/Doc/Sd1/coreClasses.xml
+++ b/Doc/Sd1/coreClasses.xml
@@ -192,9 +192,9 @@ s1.equals(s2): true</screen>
</classname><methodname>equals(...)</methodname> and
<methodname>hashCode()</methodname></title>
- <para>If <methodname>a.equals(b)</methodname> ==> <code language="java">a.hashCode() ==
- b.hashCode()</code>. <emphasis role="red">The reverse does not
- apply!</emphasis></para>
+ <para>If <methodname>a.equals(b)</methodname> ==> <code
+ language="java">a.hashCode() == b.hashCode()</code>. <emphasis
+ role="red">The reverse does not apply!</emphasis></para>
<para>Consequence: <methodname>equals()</methodname> and
<methodname>hashCode()</methodname> must be <emphasis role="red">redefined
@@ -208,8 +208,8 @@ s1.equals(s2): true</screen>
<qandadiv>
<qandaentry>
<question>
- <para>This exercise aims at a better understanding of
- <code language="java">System.out.<link
+ <para>This exercise aims at a better understanding of <code
+ language="java">System.out.<link
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/io/PrintStream.html#format-java.lang.String-java.lang.Object...-">format()</link></code>
already being used in <xref
linkend="sd1QandaSquareNumberTableFormatted"/> and other
@@ -249,7 +249,8 @@ s1.equals(s2): true</screen>
method</link> providing an additional locale argument does
indeed exist.</para>
- <para>According to <code language="java">System.out.<methodname
+ <para>According to <code
+ language="java">System.out.<methodname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/io/PrintStream.html#format-java.lang.String-java.lang.Object...-">format(...)</methodname></code>
the first argument must be of type <code language="java"
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html">String</code>.
@@ -263,10 +264,11 @@ s1.equals(s2): true</screen>
</listitem>
<listitem>
- <para>There is a one to one correspondence between each
- <code language="java">%...</code> format string and its corresponding
- argument: If n further arguments exist the format string must
- contain n <quote>%</quote> format specifiers.</para>
+ <para>There is a one to one correspondence between each <code
+ language="java">%...</code> format string and its
+ corresponding argument: If n further arguments exist the
+ format string must contain n <quote>%</quote> format
+ specifiers.</para>
</listitem>
</orderedlist>
@@ -325,8 +327,8 @@ java.util.IllegalFormatConversionException: <emphasis role="bold">d != java.lang
<question>
<para>In Exercise <xref linkend="sw1QandaCircleAreaFinal"/> you
calculated a given circle's area protecting variables against
- accidental redefinition using the <code language="java">final</code>
- modifier:</para>
+ accidental redefinition using the <code
+ language="java">final</code> modifier:</para>
<programlisting language="java">public static void main(String[] args) {
@@ -347,7 +349,8 @@ java.util.IllegalFormatConversionException: <emphasis role="bold">d != java.lang
predefines constants in <classname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Math.html">java.lang.Math</classname>
class. Read its documentation to rewrite your code thereby
- replacing your own variable <code language="java">pi</code>'s definition .</para>
+ replacing your own variable <code language="java">pi</code>'s
+ definition .</para>
<tip>
<para>You may want to read the <quote>Static Members</quote> and
@@ -417,8 +420,9 @@ public final class Math {
<para>This accounts for using the expression <varname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Math.html#field.summary">Math.PI</varname>.</para>
- <para>The careful reader may have expected an <code language="java">import</code>
- statement in order to use the <classname
+ <para>The careful reader may have expected an <code
+ language="java">import</code> statement in order to use the
+ <classname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Math.html">Math</classname>
class:</para>
@@ -449,12 +453,14 @@ public class CircleAreaCalculator {
</qandaset>
</section>
- <section xml:id="sw1SectAdvancedExternalStringExercise">
- <title>External String exercises</title>
+ <section xml:id="sd1_coreClasses_sect_qandaString">
+ <title>String exercises</title>
<qandaset defaultlabel="qanda" xml:id="sw1QandaExternalAdvancedString">
<qandadiv>
<qandaentry>
+ <title>Strings on CodingBat</title>
+
<question>
<para>Solve all remaining exercises from the <link
xlink:href="http://codingbat.com/java/String-1">String-1</link>
@@ -473,12 +479,142 @@ public class CircleAreaCalculator {
</qandaentry>
</qandadiv>
</qandaset>
- </section>
- <section xml:id="sd1_sect_emoticons">
- <title>UTF-8 and emoticons</title>
+ <qandaset defaultlabel="qanda" xml:id="sd1coreClasses_qanda_stringMask">
+ <title>Masking strings</title>
+
+ <qandadiv>
+ <qandaentry>
+ <question>
+ <para>Whenever you enter sensible information like billing details
+ you don't want others sneaking these details. On the other hand
+ you still want to recognize <abbrev>e.g.</abbrev> the account in
+ question.</para>
+
+ <para>One technique solving this conflict is masking. Considering
+ an <acronym>IBAN</acronym> bank account number we have two
+ possibilities:</para>
+
+ <glosslist>
+ <glossentry>
+ <glossterm>Full disclosure:</glossterm>
+
+ <glossdef>
+ <screen>IBAN: DE09300606010006778453</screen>
+
+ <itemizedlist>
+ <listitem>
+ <para>Advantage: Full control concerning
+ <abbrev>e.g.</abbrev> correctness of entered
+ value.</para>
+ </listitem>
+
+ <listitem>
+ <para>Disadvantage: Possibility of tapping by
+ criminals.</para>
+ </listitem>
+ </itemizedlist>
+ </glossdef>
+ </glossentry>
+
+ <glossentry>
+ <glossterm>Masking:</glossterm>
+
+ <glossdef>
+ <screen>IBAN: ##################8453</screen>
+
+ <itemizedlist>
+ <listitem>
+ <para>Advantage: Protection against felons.</para>
+ </listitem>
+
+ <listitem>
+ <para>Disadvantage: Limited distinguishability.</para>
+ </listitem>
+ </itemizedlist>
+ </glossdef>
+ </glossentry>
+ </glosslist>
+
+ <para>Implement a corresponding method:</para>
+
+ <programlisting language="java">public class Mask {
+
+ static private final int VISIBLE_POSITIONS = 4;
+
+ /**
+ * <p>Mask all but 4 positions of a given string by '#' characters. Examples:</p>
+ *
+ * <ul>
+ * <li> "You" --> "You" </li>
+ * <li> "Secret" --> "##cret" </li>
+ * <li> "Ultimate test" --> "#########test" </li>
+ * </ul>
+ *
+ * @param s The input string to be masked.
+ * @return The masked string or null in case of null input string
+ */
+ public static String mask(final String s) {
+ ...
+ return ... ;
+ }
+}</programlisting>
+
+ <para>The following unit tests provide basic testing:</para>
+
+ <programlisting language="java">public class MaskTest {
+ /**
+ * null input
+ */
+ @Test
+ public void testNullInput() {
+ Assert.assertEquals( null, Mask.mask(null) );
+ }
+
+ /**
+ * 4 or less characters should be left untouched.
+ */
+ @Test
+ public void testBelowLimit() {
+ Assert.assertEquals( "", Mask.mask("") );
+ Assert.assertEquals( "1", Mask.mask("1") );
+ Assert.assertEquals( "12", Mask.mask("12") );
+ Assert.assertEquals( "123", Mask.mask("123") );
+ Assert.assertEquals( "1234", Mask.mask("1234") );
+ }
+ /**
+ * More than 4 characters require masking.
+ */
+ @Test
+ public void testAboveLimit() {
+ Assert.assertEquals( "#2345", Mask.mask("12345") );
+ Assert.assertEquals( "##3456", Mask.mask("123456") );
+ Assert.assertEquals( "###4567", Mask.mask("1234567") );
+ Assert.assertEquals( "####5678", Mask.mask("12345678") );
+ Assert.assertEquals( "#####6789", Mask.mask("123456789") );
+ }
+}</programlisting>
+ </question>
+
+ <answer>
+ <annotation role="make">
+ <para role="eclipse">Sd1/CoreClasses/StringMask</para>
+ </annotation>
+
+ <para>Notice the presence of an alternate implementation
+ <methodname>mask2(String s)</methodname> employing yet not covered
+ <link linkend="sw1ChapterArrays">arrays</link> being based on the
+ <methodname
+ xlink:href="https://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#fill-char:A-char-">Arrays.fill
+ (...)</methodname> library method.</para>
+ </answer>
+ </qandaentry>
+ </qandadiv>
+ </qandaset>
+
+ <qandaset defaultlabel="qanda" xml:id="sd1coreClasses_qanda_emoticons">
+ <title>UTF-8 and emoticons</title>
- <qandaset defaultlabel="qanda" xml:id="sd1_qanda_emoticons">
<qandadiv>
<qandaentry>
<question>
@@ -524,12 +660,10 @@ public class CircleAreaCalculator {
</qandaentry>
</qandadiv>
</qandaset>
- </section>
-
- <section xml:id="sw1StringDigitProduct">
- <title>Analyzing strings</title>
<qandaset defaultlabel="qanda" xml:id="sw1QandaDigitStringLargestProduct">
+ <title>Analyzing strings</title>
+
<qandadiv>
<qandaentry>
<question>
@@ -593,7 +727,8 @@ public class CircleAreaCalculator {
<listitem>
<para>The <classname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html">String</classname>
- class does contain a method returning the <code language="java"
+ class does contain a method returning the <code
+ language="java"
xlink:href="https://docs.oracle.com/javase/tutorial/java/data/characters.html">char</code>
value at a given index. Read the documentation to find
it.</para>
@@ -698,22 +833,25 @@ public class CircleAreaCalculator {
}</programlisting>
<para>Unfortunately this method sometimes returns weird results:
- The argument <code language="java">"5397536978179"</code> for example returns
- -1594459696. This negative value is due to an arithmetic overflow:
- The product 5 × 3 × 9 × 7 × 5 × 3 × 6 × 9 × 7 × 8 × 1 × 7 × 9 is
- actually 2,700,507,600. This exceeds <code language="java"
+ The argument <code language="java">"5397536978179"</code> for
+ example returns -1594459696. This negative value is due to an
+ arithmetic overflow: The product 5 × 3 × 9 × 7 × 5 × 3 × 6 × 9 × 7
+ × 8 × 1 × 7 × 9 is actually 2,700,507,600. This exceeds <code
+ language="java"
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Integer.html#MAX_VALUE">MAX_VALUE</code>
of 2,147,483,647 <link
xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">being
- representable by a 4 byte <code language="java">int</code> variable</link>.</para>
+ representable by a 4 byte <code language="java">int</code>
+ variable</link>.</para>
- <para>Luckily a <code language="java">long</code> variable will be able to hold
- positive values <link
+ <para>Luckily a <code language="java">long</code> variable will be
+ able to hold positive values <link
xlink:href="https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html">up
to 9,223,372,036,854,775,807</link>. This is much larger than our
<quote>worst case</quote> 9 × 9 × 9 × 9 × 9 × 9 × 9 × 9 × 9 × 9 ×
9 × 9 × 9 = 2,541,865,828,329 value. We thus change our data type
- from <code language="java">int</code> to <code language="java">long</code>:</para>
+ from <code language="java">int</code> to <code
+ language="java">long</code>:</para>
<programlisting language="java"> private static <emphasis
role="bold">long</emphasis> getDigitProduct(final String digitWord) {
@@ -724,8 +862,8 @@ public class CircleAreaCalculator {
return product;
}</programlisting>
- <para>Assembling these pieces leaves us with the following
- <code language="java">main(...)</code> method:</para>
+ <para>Assembling these pieces leaves us with the following <code
+ language="java">main(...)</code> method:</para>
<programlisting language="java"> public static void main(String[] args) {
@@ -771,21 +909,18 @@ public class CircleAreaCalculator {
<para>The largest product of 13 successive digits stems from the
substring <code>"5576689664895</code>" <coref
linkend="sd1CoMaxProductSequence"/> starting with the last three
- digits in the fourth definition line of <code language="java">String input =
- ...</code>.</para>
+ digits in the fourth definition line of <code
+ language="java">String input = ...</code>.</para>
<screen>The substring '5576689664895' yields the largest product value 23514624000.</screen>
</answer>
</qandaentry>
</qandadiv>
</qandaset>
- </section>
-
- <section xml:id="pitfallsUsingOperatorEquals">
- <title>Pitfalls using the operator <quote>==</quote></title>
<qandaset defaultlabel="qanda" xml:id="qandaStringOperatorEquals">
- <title>String instances and equality</title>
+ <title>Pitfalls using <quote>==</quote>: Equality of
+ <classname>String</classname> instances</title>
<qandadiv>
<qandaentry>
@@ -835,18 +970,19 @@ b1.equals(b2): true </programlisting>
<calloutlist>
<callout arearefs="answerCoStringOperatorEquality-1-co"
xml:id="answerCoStringOperatorEquality-1">
- <para>The string literal <code language="java">"TestA"</code> is being
- instantiated only once: The <xref linkend="glo_Java"/>
- compiler implementation allocates only one instance of class
- String per string literal.</para>
+ <para>The string literal <code language="java">"TestA"</code>
+ is being instantiated only once: The <xref
+ linkend="glo_Java"/> compiler implementation allocates only
+ one instance of class String per string literal.</para>
<para>The string literal "TestA" (even if being defined within
different classes) always represents the same object. Thus the
- two distinct variables <code language="java">a1</code> and <code language="java">a2</code> are
- being assigned an identical reference pointing to this unique
- instance. As per definition the operator == compares two
- object references for equality and thus returns true. You
- might as well write:</para>
+ two distinct variables <code language="java">a1</code> and
+ <code language="java">a2</code> are being assigned an
+ identical reference pointing to this unique instance. As per
+ definition the operator == compares two object references for
+ equality and thus returns true. You might as well
+ write:</para>
<programlisting language="java">System.out.println(<emphasis
role="bold">"TestA" == "TestA"</emphasis>);</programlisting>
@@ -868,8 +1004,9 @@ b1.equals(b2): true </programlisting>
<screen>Hashcode a1 == 366712642, Hashcode a2 == 366712642</screen>
- <para>So <code language="java">a1</code> and <code language="java">a2</code> indeed point to
- the same object resulting in true when using the <methodname
+ <para>So <code language="java">a1</code> and <code
+ language="java">a2</code> indeed point to the same object
+ resulting in true when using the <methodname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#equals-java.lang.Object-">equals()</methodname>
method for comparison.</para>
</callout>
@@ -879,9 +1016,10 @@ b1.equals(b2): true </programlisting>
<para>Every call to the <link
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#String-java.lang.String-">String
constructor</link> will create a new string instance. Thus
- <code language="java">b1</code> and <code language="java">b2</code> will hold two distinct
- references pointing to different String instances albeit these
- two instances contain identical values. Following the above
+ <code language="java">b1</code> and <code
+ language="java">b2</code> will hold two distinct references
+ pointing to different String instances albeit these two
+ instances contain identical values. Following the above
reasoning we may execute:</para>
<programlisting language="java">System.out.println("Hashcode b1 == " + System.identityHashCode(b1) +
@@ -893,8 +1031,8 @@ b1.equals(b2): true </programlisting>
<screen>Hashcode b1 == 1829164700, Hashcode b2 == 2018699554</screen>
<para>Comparing these two reference values for equality the
- <quote>==</quote> operator thus returns
- <code language="java">false</code>.</para>
+ <quote>==</quote> operator thus returns <code
+ language="java">false</code>.</para>
<para>The <methodname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#equals-java.lang.Object-">equals()</methodname>
@@ -906,12 +1044,10 @@ b1.equals(b2): true </programlisting>
</qandaentry>
</qandadiv>
</qandaset>
- </section>
-
- <section xml:id="sd1SectStringWeirdo">
- <title>Weird, weirder, weirdest!</title>
<qandaset defaultlabel="qanda" xml:id="sd1QandaStringWeirdo">
+ <title>Weird, weirder, weirdest!</title>
+
<qandadiv>
<qandaentry>
<question>
@@ -973,18 +1109,18 @@ b1.equals(b2): true </programlisting>
</question>
<answer>
- <para>Having <code language="java">name = "An" + "ton"</code> in place we
- get:</para>
+ <para>Having <code language="java">name = "An" + "ton"</code> in
+ place we get:</para>
<screen>Content:Anton
<emphasis role="bold">Instances are equal</emphasis></screen>
<para>The Java compiler performs a clever optimization: The
- expression <code language="java">"An" + "ton"</code> is being evaluated at compile
- time. Its value is identical to the string literal
- <code language="java">"Anton"</code> and thus both variables
- <varname>name</varname> and <varname>reference</varname> will be
- initialized to a common <classname
+ expression <code language="java">"An" + "ton"</code> is being
+ evaluated at compile time. Its value is identical to the string
+ literal <code language="java">"Anton"</code> and thus both
+ variables <varname>name</varname> and <varname>reference</varname>
+ will be initialized to a common <classname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html">String</classname>
instance:</para>
@@ -996,15 +1132,15 @@ b1.equals(b2): true </programlisting>
</mediaobject>
</informalfigure>
- <para>When starting from <code language="java">name = "An".concat("ton")</code>
- the result is different:</para>
+ <para>When starting from <code language="java">name =
+ "An".concat("ton")</code> the result is different:</para>
<screen>Content:Anton
<emphasis role="bold">Instances are not equal</emphasis></screen>
<para>This time the Java compiler is unable to dynamically resolve
- the expression <code language="java">"An".concat("ton")</code> at compile time.
- Instead the method <methodname
+ the expression <code language="java">"An".concat("ton")</code> at
+ compile time. Instead the method <methodname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#concat-java.lang.String-">concat(...)</methodname>will
be called at runtime resulting in a second <classname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html">String</classname>
@@ -1034,11 +1170,12 @@ b1.equals(b2): true </programlisting>
<question>
<para>Regarding relative and absolute path specifications you may
want to read the first three paragraphs of section <quote>File
- Systems and Paths</quote> in chapter 16.</para>
+ Systems and Paths</quote> in chapter 16 of <xref
+ linkend="bib_Kurniawan2015"/>.</para>
<para>Depending on your operating system of choice absolute
- (=fully qualified) filenames are being represented in different
- ways:</para>
+ (=fully qualified) filenames are being represented
+ differently:</para>
<glosslist>
<glossentry>
@@ -1174,7 +1311,7 @@ File extension: html</screen>
<glossentry>
<glossterm>Drive letter string to character
- conversion</glossterm>
+ normalization</glossterm>
<glossdef>
<para>"C:" → <code>'C'</code></para>
@@ -1191,98 +1328,103 @@ File extension: html</screen>
</glossentry>
</glosslist>
- <tip>
- <orderedlist>
- <listitem>
- <para>You will have to deal with absolute and relative (e.g.
- <filename>../../Desktop/var.png</filename>) filename
- specifications.</para>
- </listitem>
+ <para>Hints:</para>
- <listitem>
- <para>You will have to deal with files having no extensions
- like e.g. <filename>/usr/bin/firefox</filename>. In this
- case the <code>extension</code> attribute is expected to be
- <code language="java">null</code>.</para>
- </listitem>
+ <orderedlist>
+ <listitem>
+ <para>You will have to deal with absolute and relative (e.g.
+ <filename>../../Desktop/var.png</filename>) filename
+ specifications.</para>
+ </listitem>
- <listitem>
- <para>For the sake of limiting complexity you do not have to
- consider filenames starting with a period (like
- <filename>/home/heinz/.bashrc</filename>) or containing
- multiple periods like
- <filename>../arrow.right.png</filename>.</para>
- </listitem>
+ <listitem>
+ <para>You will have to deal with files having no extensions
+ like e.g. <filename>/usr/bin/firefox</filename>. In this case
+ the <code>extension</code> attribute is expected to be <code
+ language="java">null</code> rather than <code
+ language="java">""</code>.</para>
+ </listitem>
- <listitem>
- <para>To distinguish the above mentioned system defaults for
- filename path conventions read the
- <classname>java.lang.System</classname> section of chapter 5
- <link
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/System.html">along
- with its API</link>. The book's table of system properties
- will enable your implementation to work both on Windows and
- non-Windows systems accordingly.</para>
- </listitem>
+ <listitem>
+ <para>For the sake of limiting complexity do not consider
+ filenames starting with a period (like
+ <filename>/home/heinz/.bashrc</filename>) or containing
+ multiple periods like
+ <filename>../arrow.right.png</filename>.</para>
+ </listitem>
- <listitem>
- <para>You will have to parse filenames like
- <code>"/usr/share/openvpn/hdm.conf"</code>. Exercise 7 from
- the <quote>Quiz</quote> section of chapter 5 shows an
- example dissecting a string containing tokens being
- separated by space characters using the <classname
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/util/StringTokenizer.html">java.util.StringTokenizer</classname>
- class. Read its documentation and learn how to specify
- string delimiters other than default space <code language="java">' '</code>.
- It'll allow you to dissect paths using separators '/' (Unix)
- or '\' (Windows) to break paths into components.</para>
-
- <para>Likewise you may split filenames into basename /
- extension by using <code>'.'</code> as separator.</para>
- </listitem>
+ <listitem>
+ <para>To distinguish the above mentioned system defaults for
+ filename path conventions read the
+ <classname>java.lang.System</classname> section of chapter 5
+ <link
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/System.html">along
+ with its API</link>. The table of system properties in <xref
+ linkend="bib_Kurniawan2015"/> will enable your implementation
+ to work both on Windows and non-Windows systems
+ accordingly.</para>
+ </listitem>
- <listitem>
- <para>Assembling path components may be effected by either
- using a <classname
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/StringBuffer.html">StringBuffer</classname>
- or a <classname
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/util/StringJoiner.html">StringJoiner</classname>
- instance. Mind the distinction between relative and absolute
- paths!</para>
- </listitem>
+ <listitem>
+ <para>You will have to parse filenames like
+ <code>"/usr/share/openvpn/hdm.conf"</code>. Exercise 7 from
+ the <quote>Quiz</quote> section of chapter 5 in <xref
+ linkend="bib_Kurniawan2015"/> shows an example dissecting a
+ string containing tokens being separated by space characters
+ using the <classname
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/util/StringTokenizer.html">java.util.StringTokenizer</classname>
+ class. Read its documentation and learn how to specify string
+ delimiters other than default space <code language="java">'
+ '</code>. It'll allow you to dissect paths using separators
+ '/' (Unix) or '\' (Windows) to break paths into
+ components.</para>
+
+ <para>Likewise you may split filenames into basename /
+ extension by using <code>'.'</code> as separator.</para>
+ </listitem>
- <listitem>
- <para>The methods <methodname
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#indexOf-int-">indexOf(...)</methodname>
- and <methodname
- xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#substring-int-int-">substring(...)</methodname>
- come in handy when dissecting filenames into basename and
- extension.</para>
- </listitem>
+ <listitem>
+ <para>Assembling path components may be effected by either
+ using a <classname
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/StringBuffer.html">StringBuffer</classname>
+ or a <classname
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/util/StringJoiner.html">StringJoiner</classname>
+ instance. Mind the distinction between relative and absolute
+ paths!</para>
+ </listitem>
- <listitem>
- <para>The backslash <quote>\</quote> must be escaped when
- being part of a <xref linkend="glo_Java"/> String
- literal:</para>
+ <listitem>
+ <para>The methods <methodname
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#indexOf-int-">indexOf(...)</methodname>
+ and <methodname
+ xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/String.html#substring-int-int-">substring(...)</methodname>
+ come in handy when dissecting filenames into basename and
+ extension.</para>
+ </listitem>
- <screen> String path = "C:\\programms\\openvpn\\conf\\hdm.ovpn";</screen>
- </listitem>
+ <listitem>
+ <para>The backslash <quote>\</quote> must be escaped when
+ being part of a <xref linkend="glo_Java"/> String
+ literal:</para>
- <listitem>
- <para>Unit tests may be written for Windows and non-Windows
- systems separately. Read <uri
- xlink:href="https://www.thekua.com/atwork/2008/09/running-tests-on-a-specific-os-under-junit4">https://www.thekua.com/atwork/2008/09/running-tests-on-a-specific-os-under-junit4</uri>
- how to use <methodname>Assume.assumeFalse()</methodname> /
- <methodname>Assume.assumeTrue(...)</methodname> to separate
- Windows from Unix tests.</para>
- </listitem>
+ <screen> String path = "C:\\programms\\openvpn\\conf\\hdm.ovpn";</screen>
+ </listitem>
- <listitem>
- <para>Test your implementation both on Windows and Unix-type
- platforms. The following tests may be used as a starting
- point:</para>
+ <listitem>
+ <para>Unit tests may be written for Windows and non-Windows
+ systems separately. Read <uri
+ xlink:href="https://www.thekua.com/atwork/2008/09/running-tests-on-a-specific-os-under-junit4">https://www.thekua.com/atwork/2008/09/running-tests-on-a-specific-os-under-junit4</uri>
+ how to use <methodname>Assume.assumeFalse()</methodname> /
+ <methodname>Assume.assumeTrue(...)</methodname> to separate
+ Windows from Unix tests.</para>
+ </listitem>
- <programlisting language="java">public class MetaInfoUnixTest {
+ <listitem>
+ <para>Test your implementation both on Windows and Unix-type
+ platforms. The following tests may be used as a starting
+ point:</para>
+
+ <programlisting language="java">public class MetaInfoUnixTest {
static private final boolean isWindows =
System.getProperty("os.name").startsWith("Windows");
@@ -1340,7 +1482,7 @@ File extension: html</screen>
}
}</programlisting>
- <programlisting language="java">public class MetaInfoWindowsTest {
+ <programlisting language="java">public class MetaInfoWindowsTest {
static private final boolean isWindows =
System.getProperty("os.name").startsWith("Windows");
@@ -1400,9 +1542,8 @@ File extension: html</screen>
Assert.assertEquals("gif", fmi.extension);
}
}</programlisting>
- </listitem>
- </orderedlist>
- </tip>
+ </listitem>
+ </orderedlist>
</question>
<answer>
diff --git a/Doc/Sd1/objectsClasses.xml b/Doc/Sd1/objectsClasses.xml
index 7759c6a63..8c1599dac 100644
--- a/Doc/Sd1/objectsClasses.xml
+++ b/Doc/Sd1/objectsClasses.xml
@@ -236,8 +236,9 @@ if (null == r) {
<listitem>
<para>Provide access restrictions.</para>
- <para><code language="java">public</code>, <code language="java">private</code> and
- <code language="java">protected</code> modifier</para>
+ <para><code language="java">public</code>, <code
+ language="java">private</code> and <code
+ language="java">protected</code> modifier</para>
</listitem>
<listitem>
@@ -357,7 +358,8 @@ public class Q {<lineannotation>Class def</lineannotation>
<callout arearefs="sd1_callout_importVsQualifying-4.2-co"
xml:id="sd1_callout_importVsQualifying-4.2">
- <para>Unqualified class use due to <code language="java">import</code>.</para>
+ <para>Unqualified class use due to <code
+ language="java">import</code>.</para>
</callout>
</calloutlist></td>
</tr>
@@ -584,8 +586,8 @@ public class Main {
<callout arearefs="sd1_callout_createStringAnswer1-2-co"
xml:id="sd1_callout_createStringAnswer1-2">
- <para>Due to the <code language="java">import</code> statement this is
- actually
+ <para>Due to the <code language="java">import</code>
+ statement this is actually
<package>de.hdm_stuttgart.mi.sd1.tooling</package>.<classname>String</classname>.</para>
</callout>
</calloutlist>
@@ -765,7 +767,8 @@ height=44 </screen></td>
<para>Optional <link
xlink:href="https://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html#accesscontrol-levels">access
control</link> modifier either of <code language="java">public</code>,
- <code language="java">protected</code> or <code language="java">private</code>.</para>
+ <code language="java">protected</code> or <code
+ language="java">private</code>.</para>
</callout>
<callout arearefs="sd1_callout_methodSyntax-2-co"
@@ -782,8 +785,9 @@ height=44 </screen></td>
</glossentry>
<glossentry>
- <glossterm>A data type <abbrev>e.g.</abbrev> <code language="java">int</code>,
- <code language="java">double</code>, ...</glossterm>
+ <glossterm>A data type <abbrev>e.g.</abbrev> <code
+ language="java">int</code>, <code language="java">double</code>,
+ ...</glossterm>
<glossdef>
<para>The method will return a value of the given type to its
@@ -978,10 +982,11 @@ public class Rectangle {
</question>
<answer>
- <para>First we define two instance variables <code language="java">width</code> and
- <code language="java">height</code> representing a
- <classname>Rectangle</classname>'s corresponding two parameters
- <code language="java">width</code> and <code language="java">height</code>:</para>
+ <para>First we define two instance variables <code
+ language="java">width</code> and <code language="java">height</code>
+ representing a <classname>Rectangle</classname>'s corresponding two
+ parameters <code language="java">width</code> and <code
+ language="java">height</code>:</para>
<programlisting language="java">public class Rectangle {
@@ -1039,8 +1044,8 @@ public class Rectangle {
<glossdef>
<para>The method's formal parameter <quote>height</quote>
shadows the instance variable's name being defined at class
- level. We need the <quote>this</quote> keyword in
- <code language="java">this.height = height</code> to resolve the
+ level. We need the <quote>this</quote> keyword in <code
+ language="java">this.height = height</code> to resolve the
ambiguity.</para>
</glossdef>
</glossentry>
@@ -1198,8 +1203,9 @@ public class Circle {
</question>
<answer>
- <para>We define an instance variable <code language="java">radius</code> inside
- our class <classname>Circle</classname>:</para>
+ <para>We define an instance variable <code
+ language="java">radius</code> inside our class
+ <classname>Circle</classname>:</para>
<programlisting language="java">public class Circle {
@@ -1224,11 +1230,12 @@ public class Circle {
<emphasis role="bold">this.</emphasis>radius = radius;
}</programlisting>
- <para>This requires the usage of the <code language="java">this</code> keyword to
- distinguish the formal parameter in <methodname>setRadius(double
- radius)</methodname> from the instance variable previously being
- defined within our class <classname>Circle</classname>. In other
- words: We have to resolve a name shadowing conflict.</para>
+ <para>This requires the usage of the <code
+ language="java">this</code> keyword to distinguish the formal
+ parameter in <methodname>setRadius(double radius)</methodname>
+ from the instance variable previously being defined within our
+ class <classname>Circle</classname>. In other words: We have to
+ resolve a name shadowing conflict.</para>
<para>The rest of the implementation is (quite) straightforward. A
complete class reads:</para>
@@ -1373,9 +1380,9 @@ public class Circle {
linkend="glo_SVG"/> code being written to standard output.
Use <methodname>System.out.println(...)</methodname> calls
to create the desired <xref linkend="glo_SVG"/> output. You
- may need <code language="java">\"</code> to escape double quotes as in the
- subsequent example or use single attribute quotes
- instead:</para>
+ may need <code language="java">\"</code> to escape double
+ quotes as in the subsequent example or use single attribute
+ quotes instead:</para>
<programlisting language="java">System.out.println("<rect width=\"20\"" ...</programlisting>
</glossdef>
@@ -1819,13 +1826,15 @@ public class Gamma {
<orderedlist>
<listitem>
- <para>Explain the underlying idea of the term
- <code language="java">(secondsSince_2000_01_01 / 60) % 60</code>.</para>
+ <para>Explain the underlying idea of the term <code
+ language="java">(secondsSince_2000_01_01 / 60) %
+ 60</code>.</para>
</listitem>
<listitem>
- <para>Explain the <code language="java">(int)</code> cast's necessity. Why
- is there no overflow error about to happen?</para>
+ <para>Explain the <code language="java">(int)</code> cast's
+ necessity. Why is there no overflow error about to
+ happen?</para>
</listitem>
</orderedlist>
</question>
@@ -1847,12 +1856,13 @@ public class Gamma {
</listitem>
<listitem>
- <para>The expression <code language="java">(secondsSince_2000_01_01 / 60) %
- 60</code> is of type long due to the presence of a
- <code language="java">long</code> variable. However the <quote>%</quote>
- operator guarantees the result to be in the integer range 0
- ... 59 which may thus be safely narrowed to an
- <code language="java">int</code> value.</para>
+ <para>The expression <code
+ language="java">(secondsSince_2000_01_01 / 60) % 60</code>
+ is of type long due to the presence of a <code
+ language="java">long</code> variable. However the
+ <quote>%</quote> operator guarantees the result to be in the
+ integer range 0 ... 59 which may thus be safely narrowed to
+ an <code language="java">int</code> value.</para>
</listitem>
</orderedlist>
</answer>
@@ -2323,8 +2333,8 @@ void main(void) {
<para>In <xref linkend="glo_Java"/> method signatures allow for
uniquely addressing a method within a given class e.g.:</para>
- <para>The method named <code language="java">print</code> having an int argument
- followed by a double:</para>
+ <para>The method named <code language="java">print</code> having an
+ int argument followed by a double:</para>
<programlisting language="java">print(int, double)</programlisting>
</figure>
@@ -2479,8 +2489,8 @@ a = 33;</programlisting></td>
<glossterm>Non-empty argument list</glossterm>
<glossdef>
- <para>Non-default constructor, e.g. <code language="java">obj = new
- MyClass("xyz")</code>.</para>
+ <para>Non-default constructor, e.g. <code language="java">obj =
+ new MyClass("xyz")</code>.</para>
</glossdef>
</glossentry>
</glosslist>
@@ -2558,8 +2568,8 @@ Rectangle individual = new Rectangle(2, 7); // 2 x 7 </programlisting></td>
<informaltable border="1">
<tr>
- <th colspan="2">Equivalent: <code language="java">Rectangle r = new
- Rectangle();</code></th>
+ <th colspan="2">Equivalent: <code language="java">Rectangle r =
+ new Rectangle();</code></th>
</tr>
<tr>
@@ -2730,9 +2740,10 @@ Salary:30000.00</pre>
<para>Currently both classes (hopefully!) reside in the same
package <package>company</package>. We will assume the two
- attributes age and salary yet have no <code language="java">public</code>,
- <code language="java">private</code> or <code language="java">protected</code> access modifiers
- :</para>
+ attributes age and salary yet have no <code
+ language="java">public</code>, <code
+ language="java">private</code> or <code
+ language="java">protected</code> access modifiers :</para>
<programlisting language="java">package company;
@@ -2783,8 +2794,9 @@ public class Driver {
<tip>
<para>Read the section on <code language="java">public</code>,
- <code language="java">private</code>, <code language="java">protected</code> and default
- access level.</para>
+ <code language="java">private</code>, <code
+ language="java">protected</code> and default access
+ level.</para>
</tip>
</question>
@@ -2792,8 +2804,8 @@ public class Driver {
<para>Moving the <classname>Employee</classname> class from its
<package>company</package> package to <package>model</package>
changes just one line of code in
- <filename>Employee.java</filename> namely its
- <code language="java">package</code> declaration. It also adds an
+ <filename>Employee.java</filename> namely its <code
+ language="java">package</code> declaration. It also adds an
<code language="java">import</code> statement</para>
<informaltable border="1">
@@ -2898,8 +2910,8 @@ public class Driver {
(<quote>quick and dirty</quote>)</glossterm>
<glossdef>
- <para>Raising access level from default to
- <code language="java">public</code> thereby violating the <link
+ <para>Raising access level from default to <code
+ language="java">public</code> thereby violating the <link
xlink:href="https://en.wikipedia.org/wiki/Encapsulation_(object-oriented_programming)">principle
of encapsulation</link>:</para>
@@ -2912,8 +2924,8 @@ public class Driver {
<glossentry>
<glossterm>Providing a so called setter method in our
- <classname>Employee</classname> class of access type
- <code language="java">public</code></glossterm>
+ <classname>Employee</classname> class of access type <code
+ language="java">public</code></glossterm>
<glossdef>
<informaltable border="1">
@@ -3008,11 +3020,13 @@ public class Driver {
}</programlisting>
<para>This compiles correctly but yields an unexpected result:
- The constructor variables <code language="java">int age</code> and <code language="java">int
- salary</code> will be assigned to themselves as being indicated
- by a corresponding compiler warning. More important their values
- don't make it to the <code language="java">age</code> and <code language="java">salary</code>
- attributes being defined on class level.</para>
+ The constructor variables <code language="java">int age</code>
+ and <code language="java">int salary</code> will be assigned to
+ themselves as being indicated by a corresponding compiler
+ warning. More important their values don't make it to the <code
+ language="java">age</code> and <code
+ language="java">salary</code> attributes being defined on class
+ level.</para>
<para>Apparently we are missing something. Explain these two
compiler warnings. How can the underlying conflict be
@@ -3028,9 +3042,9 @@ public class Driver {
<answer>
<para>When choosing <methodname>public Employee(int age, double
- salary)</methodname> we have two sets of variables
- (<code language="java">age</code>, <code language="java">salary</code>) in two different
- conflicting scopes:</para>
+ salary)</methodname> we have two sets of variables (<code
+ language="java">age</code>, <code language="java">salary</code>)
+ in two different conflicting scopes:</para>
<glosslist>
<glossentry>
@@ -3058,15 +3072,18 @@ public class Driver {
<para>Within the constructor's method body the parameter list
scope will take precedence over class scope. Thus the assignment
- <code language="java">age = age</code> will assign the constructor's argument
- <code language="java">age</code> to itself rather than assigning it to the
- instance variable <code language="java">age</code> being defined within class
+ <code language="java">age = age</code> will assign the
+ constructor's argument <code language="java">age</code> to
+ itself rather than assigning it to the instance variable <code
+ language="java">age</code> being defined within class
scope.</para>
<para>We may explicitly resolve this scope conflict in our
- favour by qualifying the instance variables <code language="java">age</code> and
- <code language="java">salary</code> using their respective scope being
- represented by the <code language="java">this</code> keyword:</para>
+ favour by qualifying the instance variables <code
+ language="java">age</code> and <code
+ language="java">salary</code> using their respective scope being
+ represented by the <code language="java">this</code>
+ keyword:</para>
<programlisting language="java"> public Employee(int age, double salary) {
// The "this" keyword refers to class scope
@@ -3166,8 +3183,8 @@ public class Driver {
<calloutlist>
<callout arearefs="sd1_callout_clubStaticMembercount-1-co"
xml:id="sd1_callout_clubStaticMembercount-1">
- <para>The keyword <code language="java">static</code> defines <code language="java">memberCount</code>
- as a <emphasis
+ <para>The keyword <code language="java">static</code> defines <code
+ language="java">memberCount</code> as a <emphasis
xlink:href="https://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html">class
variable</emphasis> keeping track of the club's overall member
count.</para>
@@ -3175,8 +3192,9 @@ public class Driver {
<callout arearefs="sd1_callout_clubStaticMembercount-2-co"
xml:id="sd1_callout_clubStaticMembercount-2">
- <para><code language="java">memberNumber</code> and <code language="java">name</code> being defined as
- instance variables.</para>
+ <para><code language="java">memberNumber</code> and <code
+ language="java">name</code> being defined as instance
+ variables.</para>
</callout>
<callout arearefs="sd1_callout_clubStaticMembercount-3-co"
@@ -3243,8 +3261,8 @@ public class Driver {
<callout arearefs="sd1_callout_clubMembershipAccessHeadcount-1-co"
xml:id="sd1_callout_clubMembershipAccessHeadcount-1">
<para><methodname>getMemberCount()</methodname> being defined as
- <emphasis role="bold">class method</emphasis> by virtue of the
- <code language="java">static</code> keyword.</para>
+ <emphasis role="bold">class method</emphasis> by virtue of the <code
+ language="java">static</code> keyword.</para>
</callout>
<callout arearefs="sd1_callout_clubMembershipAccessHeadcount-2-co"
@@ -3354,7 +3372,8 @@ Club's member count:3</screen>
<para>Is it possible to implement
<methodname>getDetails()</methodname> from <xref
linkend="sd1_fig_staticMemberConstructorImplement"/> as a
- class method by adding <code language="java">static</code>?</para>
+ class method by adding <code
+ language="java">static</code>?</para>
</listitem>
<listitem>
@@ -3368,7 +3387,8 @@ Club's member count:3</screen>
<answer>
<orderedlist>
<listitem>
- <para>Adding the <code language="java">static</code> modifier yields:</para>
+ <para>Adding the <code language="java">static</code> modifier
+ yields:</para>
<programlisting language="none">public class ClubMember {
...
@@ -3425,9 +3445,9 @@ model/ClubMember.java:20: error: non-static variable memberNumber
System.out.println(karen.getDetails());
System.out.println("Club's headcount:" + <emphasis role="red">john.</emphasis>getMemberCount());</programlisting>
- <para>This is actually a regression with respect to the
- <code language="java">static</code> class method variant since the number of
- club members does not depend on individual member
+ <para>This is actually a regression with respect to the <code
+ language="java">static</code> class method variant since the
+ number of club members does not depend on individual member
instances.</para>
</listitem>
</orderedlist>
@@ -3544,8 +3564,9 @@ public class <link
</qandaset>
<qandaset defaultlabel="qanda" xml:id="sd1QandaRewriteLoop">
- <title>A method for printing square numbers using <code language="java">for</code>,
- <code language="java">while</code> and <code language="java">do</code> ... <code language="java">while</code></title>
+ <title>A method for printing square numbers using <code
+ language="java">for</code>, <code language="java">while</code> and <code
+ language="java">do</code> ... <code language="java">while</code></title>
<qandadiv>
<qandaentry>
@@ -3583,7 +3604,8 @@ public class <link
<orderedlist>
<listitem>
- <para><code language="java">while (...) {...}</code> loop:</para>
+ <para><code language="java">while (...) {...}</code>
+ loop:</para>
<programlisting language="java"> ...
public static void while_squareNumbers(final int limit) {
@@ -3597,7 +3619,8 @@ public class <link
</listitem>
<listitem>
- <para><code language="java">do {...} while(...)</code> loop:</para>
+ <para><code language="java">do {...} while(...)</code>
+ loop:</para>
<programlisting language="java"> ...
public static void while_squareNumbers(final int limit) {
@@ -3612,8 +3635,8 @@ public class <link
</listitem>
</orderedlist>
- <para>Caveat: The <code language="java">do {...} while(...)</code> part is a
- little bit tricky. Read the method's documentation
+ <para>Caveat: The <code language="java">do {...} while(...)</code>
+ part is a little bit tricky. Read the method's documentation
<emphasis><emphasis role="bold">precisely</emphasis></emphasis> to
avoid a common pitfall.</para>
@@ -3639,8 +3662,8 @@ public class <link
System.out.println("Finished computing square numbers");
} ...</programlisting>
- <para>Its tempting to implement a <code language="java">do ... while</code> in a
- similar fashion:</para>
+ <para>Its tempting to implement a <code language="java">do ...
+ while</code> in a similar fashion:</para>
<programlisting language="java">public class LoopExample {
...
@@ -3674,14 +3697,16 @@ public class <link
System.out.println("Finished computing square numbers");
}</programlisting>
- <para>This required if-clause reminds us that a <code language="java">do {...}
- while (...)</code> is an ill-suited choice here in comparison to a
- <code language="java">while(...){...}</code> or a <code language="java">for(...){...}</code>
- loop.</para>
+ <para>This required if-clause reminds us that a <code
+ language="java">do {...} while (...)</code> is an ill-suited
+ choice here in comparison to a <code
+ language="java">while(...){...}</code> or a <code
+ language="java">for(...){...}</code> loop.</para>
- <para>Actually a <code language="java">for(...){...} loop is the best choice here
- since the number of iterations is known in advance, the increment
- is constant and it allows for initialization</code>.</para>
+ <para>Actually a <code language="java">for(...){...} loop is the
+ best choice here since the number of iterations is known in
+ advance, the increment is constant and it allows for
+ initialization</code>.</para>
</answer>
</qandaentry>
</qandadiv>
@@ -3829,8 +3854,9 @@ public class <link
declaration</glossterm>
<glossdef>
- <para><code language="java">private double balance</code>, <code language="java">public
- void setBalance(double balance)</code></para>
+ <para><code language="java">private double balance</code>,
+ <code language="java">public void setBalance(double
+ balance)</code></para>
</glossdef>
</glossentry>
@@ -3839,9 +3865,9 @@ public class <link
declaration</glossterm>
<glossdef>
- <para><code language="java">private static double </code>interestRate,
- <code language="java">public static void setInterestRate(double
- z)</code></para>
+ <para><code language="java">private static double
+ </code>interestRate, <code language="java">public static
+ void setInterestRate(double z)</code></para>
</glossdef>
</glossentry>
</glosslist>
@@ -3867,17 +3893,19 @@ public class <link
interestRate = z; // in contrast interestRate has
} // class scope.</programlisting>
- <para>The formal variable's name <quote><code language="java">z</code></quote>
- may be <emphasis>consistently</emphasis> renamed to any other
- legal, non-conflicting value like
- <quote><code language="java">myFunnyVariableName</code></quote>:</para>
+ <para>The formal variable's name <quote><code
+ language="java">z</code></quote> may be
+ <emphasis>consistently</emphasis> renamed to any other legal,
+ non-conflicting value like <quote><code
+ language="java">myFunnyVariableName</code></quote>:</para>
<programlisting language="java"> public static void setInterestRate(double myFunnyVariableName) {
interestRate = myFunnyVariableName;
}</programlisting>
<para>Alternatively name shadowing conflicts may be resolved by
- using the keyword <emphasis><code language="java">this</code></emphasis> <coref
+ using the keyword <emphasis><code
+ language="java">this</code></emphasis> <coref
linkend="sd1ListingThis"/>:</para>
<programlisting language="java">public class Konto {
@@ -3972,19 +4000,20 @@ public class <link
<qandadiv>
<qandaentry>
<question>
- <para>Our current <classname>Account</classname> class does not handle
- negative balances accordingly. Typically banks will charge a
- different interest rate whenever an account is in debt i.e.
- having a negative balance. In this case a second so called
- default interest rate (being significantly higher) will be
- applied.</para>
+ <para>Our current <classname>Account</classname> class does
+ not handle negative balances accordingly. Typically banks will
+ charge a different interest rate whenever an account is in
+ debt i.e. having a negative balance. In this case a second so
+ called default interest rate (being significantly higher) will
+ be applied.</para>
<para>Extend the current project by adding a new instance
variable <varname>defaultInterestRate</varname> along with
getter and setter methods. Then change the implementation of
- <code language="java">applyInterest()</code> and <code language="java">applyInterest(int
- years)</code> by using the correct interest value according to
- the account's balance being positive or negative.</para>
+ <code language="java">applyInterest()</code> and <code
+ language="java">applyInterest(int years)</code> by using the
+ correct interest value according to the account's balance
+ being positive or negative.</para>
<caution>
<para>Do not forget to change the <command>Javadoc</command>
@@ -3997,9 +4026,9 @@ public class <link
<para role="eclipse">Sd1/interest/V2</para>
</annotation>
- <para>We introduce a new variable
- <code language="java">defaultInterestRate</code> to cover negative balance
- values:</para>
+ <para>We introduce a new variable <code
+ language="java">defaultInterestRate</code> to cover negative
+ balance values:</para>
<programlisting language="java"> private static double
interestRate = 1.5, // applied to positive balances
@@ -4064,24 +4093,28 @@ int sum = a + b;</programlisting>
</question>
<answer>
- <para>The sum of a and b may either exceed
- <code language="java">java.lang.Integer.MAX_VALUE</code> or in turn may be
- less than <code language="java">java.lang.Integer.MIN_VALUE</code>. To avoid
- this type of overflow error our variable <code language="java">sum</code> may
- be declared of type long:</para>
+ <para>The sum of a and b may either exceed <code
+ language="java">java.lang.Integer.MAX_VALUE</code> or in turn
+ may be less than <code
+ language="java">java.lang.Integer.MIN_VALUE</code>. To avoid
+ this type of overflow error our variable <code
+ language="java">sum</code> may be declared of type
+ long:</para>
<programlisting language="java">int a = ..., b = ...;
...// statements being omitted
long sum = a + b;</programlisting>
<para>Unfortunately this does not (yet) help at all: Since
- both operands <code language="java">a</code> and <code language="java">b</code> are of type
- <code language="java">int</code> the expression <code language="java">a + b</code> is also of
- type int and will be evaluated as such. To circumvent this
- problem we have to cast at least one operand to type
- <code language="java">long</code> prior to computing the sum. This works since
- the cast operator <code language="java">(long)</code> does have higher
- priority than the <quote>+</quote> operator</para>
+ both operands <code language="java">a</code> and <code
+ language="java">b</code> are of type <code
+ language="java">int</code> the expression <code
+ language="java">a + b</code> is also of type int and will be
+ evaluated as such. To circumvent this problem we have to cast
+ at least one operand to type <code language="java">long</code>
+ prior to computing the sum. This works since the cast operator
+ <code language="java">(long)</code> does have higher priority
+ than the <quote>+</quote> operator</para>
<programlisting language="java">int a = ..., b = ...;
...// statements being omitted
@@ -4101,8 +4134,8 @@ long sum = (long)a + b;</programlisting>
<question>
<para>Implement a class representing fractions. You may find a
dummy implementation containing some (not yet working) sample
- usage code being contained in a <code language="java">main()</code>
- method.</para>
+ usage code being contained in a <code
+ language="java">main()</code> method.</para>
<annotation role="make">
<para role="eclipse">Sd1/fraction/V05</para>
@@ -4168,13 +4201,14 @@ long sum = (long)a + b;</programlisting>
</question>
<answer>
- <para>Incrementing <code language="java">++a</code> and decrementing
- <code language="java">--c</code> happens prior to adding / subtracting their
- values to the variable <code language="java">result</code> (prefix notation).
- The increment operation <code language="java">b--</code> in contrast happens
- after being being subtracted from variable <code language="java">result</code>
- (postfix notation). The following code snippet is thus
- equivalent:</para>
+ <para>Incrementing <code language="java">++a</code> and
+ decrementing <code language="java">--c</code> happens prior to
+ adding / subtracting their values to the variable <code
+ language="java">result</code> (prefix notation). The increment
+ operation <code language="java">b--</code> in contrast happens
+ after being being subtracted from variable <code
+ language="java">result</code> (postfix notation). The
+ following code snippet is thus equivalent:</para>
<programlisting language="java"> int a = 6,
b = 7,
@@ -4392,9 +4426,9 @@ long sum = (long)a + b;</programlisting>
numerator *= i;
}</programlisting>
- <para>In this case our numerator variable of type
- <code language="java">long</code> will be set to a value 22! (factorial).
- Consider a simple demo code snippet among with its
+ <para>In this case our numerator variable of type <code
+ language="java">long</code> will be set to a value 22!
+ (factorial). Consider a simple demo code snippet among with its
result:</para>
<informaltable border="1">
@@ -4677,9 +4711,9 @@ Largest long value:9223372036854775807</screen></td>
<qandaentry>
<question>
<para>We recall <xref linkend="sd1SectFraction"/>. So far no one
- demanded cancelling fractions. Yet calling <code language="java">new
- Fraction(4,8)</code> will create an instance internally being
- represented by <inlineequation>
+ demanded cancelling fractions. Yet calling <code
+ language="java">new Fraction(4,8)</code> will create an instance
+ internally being represented by <inlineequation>
<m:math display="inline">
<m:mfrac>
<m:mi>4</m:mi>
@@ -4712,10 +4746,10 @@ Largest long value:9223372036854775807</screen></td>
return ??;
}</programlisting>
- <para>With respect to fractions one or both parameters
- <code language="java">a</code> and <code language="java">b</code> <coref
- linkend="sd1ListEuclidNeg"/> may be zero or negative. So we do
- have several special cases to handle:</para>
+ <para>With respect to fractions one or both parameters <code
+ language="java">a</code> and <code language="java">b</code>
+ <coref linkend="sd1ListEuclidNeg"/> may be zero or negative. So
+ we do have several special cases to handle:</para>
<glosslist>
<glossentry>
@@ -4974,11 +5008,11 @@ Largest long value:9223372036854775807</screen></td>
</m:mrow>
</m:math>
</inlineequation>. Our simple implementation proposal would
- call <code language="java">new Fraction(12, 14)</code> only to discover a
- <acronym>GCD</acronym> value of 4. Having larger argument values
- this might cause an unnecessary overflow. Moreover the
- <acronym>GCD</acronym> calculation will take longer than
- needed.</para>
+ call <code language="java">new Fraction(12, 14)</code> only to
+ discover a <acronym>GCD</acronym> value of 4. Having larger
+ argument values this might cause an unnecessary overflow.
+ Moreover the <acronym>GCD</acronym> calculation will take longer
+ than needed.</para>
<para>We may instead transform the term in question by
exchanging the numerators like <inlineequation>
@@ -5000,9 +5034,9 @@ Largest long value:9223372036854775807</screen></td>
</m:mrow>
</m:math>
</inlineequation> to enable cancelling <emphasis
- role="bold">prior</emphasis> to multiplying. Now the call
- <code language="java">new Fraction(4,2)</code> will construct the representation
- <inlineequation>
+ role="bold">prior</emphasis> to multiplying. Now the call <code
+ language="java">new Fraction(4,2)</code> will construct the
+ representation <inlineequation>
<m:math display="inline">
<m:mfrac>
<m:mi>2</m:mi>
@@ -5207,8 +5241,9 @@ public class Math {
<orderedlist>
<listitem>
<para>The method's signature looks slightly weird: It does
- expect an argument of type <code language="java">int</code> but returns a
- <code language="java">long</code> value. Explain the underlying
+ expect an argument of type <code
+ language="java">int</code> but returns a <code
+ language="java">long</code> value. Explain the underlying
ratio.</para>
</listitem>
@@ -5236,10 +5271,10 @@ public class Math {
<orderedlist>
<listitem>
<para>Returning a long is sensible since even small
- argument values in return yield large factorials.
- <code language="java">long</code> is the best (largest) choice among the
- <xref linkend="glo_Java"/> built-in integer types.
- Consider the following example code:</para>
+ argument values in return yield large factorials. <code
+ language="java">long</code> is the best (largest) choice
+ among the <xref linkend="glo_Java"/> built-in integer
+ types. Consider the following example code:</para>
<programlisting language="java"> public static void main(String[] args) {
@@ -5278,22 +5313,23 @@ public class Math {
<m:mo>!</m:mo>
</m:mrow>
</m:math>
- </inlineequation> we already see <code language="java">long</code>
- overflow related errors. Thus allowing for even larger
- <code language="java">long</code> arguments instead of <code language="java">int</code>
- does not make sense at all.</para>
+ </inlineequation> we already see <code
+ language="java">long</code> overflow related errors. Thus
+ allowing for even larger <code language="java">long</code>
+ arguments instead of <code language="java">int</code> does
+ not make sense at all.</para>
<para>Since <quote>21</quote> is pretty small we might
- favour <code language="java">short</code> (or even <code language="java">char</code>) as
- argument type:</para>
+ favour <code language="java">short</code> (or even <code
+ language="java">char</code>) as argument type:</para>
<programlisting language="java">static public long factorial(short n) { ... }</programlisting>
<para>This however is a bad idea: Even simple expressions
would be flagged as compile time errors since both integer
literals and arithmetic expressions in <xref
- linkend="glo_Java"/> evaluate to the data type
- <code language="java">int</code>:</para>
+ linkend="glo_Java"/> evaluate to the data type <code
+ language="java">int</code>:</para>
<programlisting language="java">// Compile time error:
// The method factorial(short) in the type
@@ -6294,9 +6330,10 @@ Ratio Recursive / Loop: 65554</screen></td>
}</programlisting>
</figure>
- <para>Compare your results using <code language="java">seriesLimit=8</code>
- terms and the corresponding values from the professional
- implementation <link
+ <para>Compare your results using <code
+ language="java">seriesLimit=8</code> terms and the
+ corresponding values from the professional implementation
+ <link
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Math.html#exp-double">java.lang.Math.exp</link>
by calculating <inlineequation>
<m:math display="inline">
@@ -8136,8 +8173,9 @@ sin(4 * PI)=4518.2187229323445, difference=4518.2187229323445</screen>
<para>Hint: The standard function <methodname
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Math.html#floor-double-">Math.rint(double)</methodname>
- could be helpful: It may turn e.g. 4.47 (<code language="java">double</code>)
- to 4 (<code language="java">long</code>).</para>
+ could be helpful: It may turn e.g. 4.47 (<code
+ language="java">double</code>) to 4 (<code
+ language="java">long</code>).</para>
</question>
<answer>
@@ -8201,10 +8239,13 @@ sin(4 * PI)=4518.2187229323445, difference=4518.2187229323445</screen>
<glossdef>
<para>Holding data within own memory location.</para>
- <para>Eight value types in <xref linkend="glo_Java"/>:
- <code language="java">byte</code>, <code language="java">short</code>, <code language="java">int</code>,
- <code language="java">long</code>, <code language="java">float</code>, <code language="java">double</code>,
- <code language="java">char</code> and <code language="java">boolean</code>.</para>
+ <para>Eight value types in <xref linkend="glo_Java"/>: <code
+ language="java">byte</code>, <code language="java">short</code>,
+ <code language="java">int</code>, <code
+ language="java">long</code>, <code language="java">float</code>,
+ <code language="java">double</code>, <code
+ language="java">char</code> and <code
+ language="java">boolean</code>.</para>
</glossdef>
</glossentry>
@@ -8561,8 +8602,8 @@ After printDuplicateValue: <emphasis role="red">6</emphasis></screen></td>
<glossterm>Instance scope</glossterm>
<glossdef>
- <para>Object lifetime: <code language="java">new ...()</code> until being garbage
- collected.</para>
+ <para>Object lifetime: <code language="java">new ...()</code>
+ until being garbage collected.</para>
</glossdef>
</glossentry>
@@ -8570,8 +8611,8 @@ After printDuplicateValue: <emphasis role="red">6</emphasis></screen></td>
<glossterm>Method scope</glossterm>
<glossdef>
- <para>During method call until (possibly implicit)
- <code language="java">return</code>.</para>
+ <para>During method call until (possibly implicit) <code
+ language="java">return</code>.</para>
</glossdef>
</glossentry>
</glosslist>
@@ -8649,8 +8690,8 @@ After printDuplicateValue: <emphasis role="red">6</emphasis></screen></td>
<tr>
<td valign="top"><emphasis role="bold">empty</emphasis></td>
- <td valign="top"><para><code language="java">true</code> if and only if the stack is
- empty. Read only.</para></td>
+ <td valign="top"><para><code language="java">true</code> if and only
+ if the stack is empty. Read only.</para></td>
</tr>
</informaltable>
</figure>
@@ -9068,8 +9109,8 @@ Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
</figure>
<figure xml:id="sd1_fig_equalsDoubleCaveat">
- <title>Caution comparing <code language="java">float</code> /
- <code language="java">double</code></title>
+ <title>Caution comparing <code language="java">float</code> / <code
+ language="java">double</code></title>
<mediaobject>
<imageobject>
@@ -9347,9 +9388,10 @@ Elapsed time: 1169805 nanoseconds</screen>
Expected :0
Actual :10</screen>
- <para>We forgot to deal with negative <code language="java">limit</code> values.
- Our sum is supposed to start with 0 so negative <code language="java">limit</code>
- values should yield 0 like in our loop based solution:</para>
+ <para>We forgot to deal with negative <code
+ language="java">limit</code> values. Our sum is supposed to start
+ with 0 so negative <code language="java">limit</code> values
+ should yield 0 like in our loop based solution:</para>
<programlisting language="java">public static long getSum(int limit) {
if (limit < 0) {
@@ -9367,10 +9409,12 @@ Actual :10</screen>
Expected :2147450880
Actual :-32768</screen>
- <para>This actually is a showstopper for large <code language="java">limit</code>
- values: The algebraic value of <code language="java">limit * (limit + 1) /
- 2</code> might still fit into an <code language="java">int</code>. But <code language="java">limit
- * (limit + 1)</code> itself not yet divided by 2 may exceed <code language="java"
+ <para>This actually is a showstopper for large <code
+ language="java">limit</code> values: The algebraic value of <code
+ language="java">limit * (limit + 1) / 2</code> might still fit
+ into an <code language="java">int</code>. But <code
+ language="java">limit * (limit + 1)</code> itself not yet divided
+ by 2 may exceed <code language="java"
xlink:href="https://docs.oracle.com/javase/9/docs/api/java/lang/Integer.html#MAX_VALUE">Integer.MAX_VALUE</code>.
Since the multiplication happens prior to dividing by 2 we see
this overflow error happen.</para>
@@ -9387,12 +9431,13 @@ Actual :-32768</screen>
}
}</programlisting>
- <para>This is only correct if <code language="java">limit</code> is even.
- Otherwise division by 2 leaves us with a remainder of 1.</para>
+ <para>This is only correct if <code language="java">limit</code>
+ is even. Otherwise division by 2 leaves us with a remainder of
+ 1.</para>
- <para>However if <code language="java">limit</code> is uneven the second factor
- <code language="java">limit + 1</code> will be even. This observation leads us to
- the final solution:</para>
+ <para>However if <code language="java">limit</code> is uneven the
+ second factor <code language="java">limit + 1</code> will be even.
+ This observation leads us to the final solution:</para>
<programlisting language="java">public static long getSum(int limit) {
if (limit < 0) {
@@ -9418,528 +9463,4 @@ Elapsed time: 25422 nanoseconds</screen>
</qandadiv>
</qandaset>
</section>
-
- <section xml:id="sw1ChapterObjectsClassesCannon">
- <title>Simulating a car jump</title>
-
- <para>We want to model a <link
- xlink:href="https://www.sciencechannel.com/tv-shows/outrageous-acts-of-science/videos/insane-car-jump">car
- jump</link> to be used in a computer game. <link
- xlink:href="https://www.sciencechannel.com/tv-shows/outrageous-acts-of-science/videos/insane-car-jump">Watch
- the video</link> to understand the subsequent explanations</para>
-
- <section xml:id="sd1SectCarJumpBasic">
- <title>A basic model, rolling downwards</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaCarJumpBasic">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Our Java model will be implemented in a class
- <classname>CarJump</classname>. We start by two simple
- assumptions:</para>
-
- <itemizedlist>
- <listitem>
- <para>Initially our car will gain speed just just rolling
- down the slope.</para>
- </listitem>
-
- <listitem>
- <para>The car's motor will remain idle and in particular
- will not provide any additional thrust.</para>
- </listitem>
-
- <listitem>
- <para>Friction and (airborne) drag shall be
- neglected.</para>
- </listitem>
- </itemizedlist>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/Fig/carSlope.fig"/>
- </imageobject>
- </mediaobject>
-
- <para>Watch <link
- xlink:href="/Sd1/Ref/Fig/carSlope.pdf">carJump.pdf</link> for
- parameter details of the above image. In this exercise we start
- by just considering the car's velocity when getting airborne. To
- get an implementation sketch you may want to import the
- subsequently described Maven skeleton and continue its
- implementation.</para>
-
- <annotation role="make">
- <para role="eclipse">Sd1/CarJump/V1</para>
- </annotation>
-
- <para>Do not forget to define suitable unit tests like:</para>
-
- <programlisting language="java">package ...
-import org.junit.Assert;
-import org.junit.Test;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-/**
- * Unit test for car jump model.
- */
-public class ModelTest {
- /**
- * Checking approximate velocity value.
- */
- @Test
- public void testAirborneVelocity() {
-
- final CarJump jump = new CarJump(20, 4);
-
- Assert.assertEquals(17.71, jump.getSlopeSpeed(), 1.E-2);
- }
-}</programlisting>
-
- <tip>
- <orderedlist>
- <listitem>
- <para>This exercise requires some physics knowledge. Since
- our car starts from height <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>1</m:mn>
- </m:msub>
- </m:math>
- </inlineequation> and gets airborne at <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>2</m:mn>
- </m:msub>
- </m:math>
- </inlineequation> we can easily calculate the amount of
- potential energy. According to the well known formula
- relating a bodies velocity and kinetic energy this allows
- for calculating the car's velocity.</para>
- </listitem>
-
- <listitem>
- <para>The project skeleton does not yet provide instance
- variables describing the model's internal state.
- Furthermore the desired velocity is depending on these
- model parameters.</para>
- </listitem>
- </orderedlist>
- </tip>
- </question>
-
- <answer>
- <para>With <inlineequation>
- <m:math display="inline">
- <m:mi>g</m:mi>
- </m:math>
- </inlineequation> being the gravity acceleration constant of
- <inlineequation>
- <m:math display="inline">
- <m:mrow>
- <m:mi>9.81</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mfrac>
- <m:mi>m</m:mi>
-
- <m:msup>
- <m:mi>s</m:mi>
-
- <m:mi>2</m:mi>
- </m:msup>
- </m:mfrac>
- </m:mrow>
- </m:math>
- </inlineequation> we have:</para>
-
- <glosslist>
- <glossentry>
- <glossterm>The car's (difference in) potential Energy when
- rolling from <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>1</m:mn>
- </m:msub>
- </m:math>
- </inlineequation> down to <inlineequation>
- <m:math display="inline">
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>2</m:mn>
- </m:msub>
- </m:math>
- </inlineequation> :</glossterm>
-
- <glossdef>
- <informalequation>
- <m:math display="block">
- <m:mrow>
- <m:msub>
- <m:mi>E</m:mi>
-
- <m:mi>p</m:mi>
- </m:msub>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mi>m</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mi>g</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mrow>
- <m:mo>(</m:mo>
-
- <m:mrow>
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>1</m:mn>
- </m:msub>
-
- <m:mo>-</m:mo>
-
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>2</m:mn>
- </m:msub>
- </m:mrow>
-
- <m:mo>)</m:mo>
- </m:mrow>
- </m:mrow>
- </m:mrow>
- </m:math>
- </informalequation>
- </glossdef>
- </glossentry>
-
- <glossentry>
- <glossterm>The car's kinetic Energy due to its speed
- <inlineequation>
- <m:math display="inline">
- <m:mi>v</m:mi>
- </m:math>
- </inlineequation> when leaving the ascending
- slope:</glossterm>
-
- <glossdef>
- <informalequation>
- <m:math display="block">
- <m:mrow>
- <m:msub>
- <m:mi>E</m:mi>
-
- <m:mi>k</m:mi>
- </m:msub>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mfrac>
- <m:mi>1</m:mi>
-
- <m:mi>2</m:mi>
- </m:mfrac>
-
- <m:mo>â¢</m:mo>
-
- <m:mi>m</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:msup>
- <m:mi>v</m:mi>
-
- <m:mi>2</m:mi>
- </m:msup>
- </m:mrow>
- </m:mrow>
- </m:math>
- </informalequation>
- </glossdef>
- </glossentry>
-
- <glossentry>
- <glossterm>The car's potential and kinetic energy amounts
- are equal:</glossterm>
-
- <glossdef>
- <informalequation>
- <m:math display="inline">
- <m:mrow>
- <m:msub>
- <m:mi>E</m:mi>
-
- <m:mi>p</m:mi>
- </m:msub>
-
- <m:mo>=</m:mo>
-
- <m:msub>
- <m:mi>E</m:mi>
-
- <m:mi>k</m:mi>
- </m:msub>
- </m:mrow>
- </m:math>
- </informalequation>
- </glossdef>
- </glossentry>
- </glosslist>
-
- <para>We thus conclude:</para>
-
- <informalequation>
- <m:math display="inline">
- <m:mrow>
- <m:mi>v</m:mi>
-
- <m:mo>=</m:mo>
-
- <m:msqrt>
- <m:mrow>
- <m:mi>2</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mi>g</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mrow>
- <m:mo>(</m:mo>
-
- <m:mrow>
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>1</m:mn>
- </m:msub>
-
- <m:mo>-</m:mo>
-
- <m:msub>
- <m:mi>h</m:mi>
-
- <m:mn>2</m:mn>
- </m:msub>
- </m:mrow>
-
- <m:mo>)</m:mo>
- </m:mrow>
- </m:mrow>
- </m:msqrt>
- </m:mrow>
- </m:math>
- </informalequation>
-
- <para>This leads to the following implementation:</para>
-
- <annotation role="make">
- <para role="eclipse">Sd1/CarJump/V2</para>
- </annotation>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
-
- <section xml:id="sd1SectCarJumpGettingAirborne">
- <title>Getting airborne</title>
-
- <qandaset defaultlabel="qanda" xml:id="sd1QandaCarJumpGettingAirborne">
- <qandadiv>
- <qandaentry>
- <question>
- <para>Our game developer asks for the following (derived)
- parameters:</para>
-
- <itemizedlist>
- <listitem>
- <para>The car's horizontal distance <inlineequation>
- <m:math display="inline">
- <m:mi>d</m:mi>
- </m:math>
- </inlineequation> (see previous exercise pdf
- figure).</para>
- </listitem>
-
- <listitem>
- <para>The car's maximum height above ground during its
- flight.</para>
- </listitem>
- </itemizedlist>
-
- <tip>
- <para>The car will travel the ascending slope at an angle of
- <inlineequation>
- <m:math display="inline">
- <m:mi>α</m:mi>
- </m:math>
- </inlineequation> given in ordinary degrees ranging from 0
- to 90. You can decompose the car's velocity into its
- horizontal and vertical components (See pdf for
- details):</para>
-
- <mediaobject>
- <imageobject>
- <imagedata fileref="Ref/Fig/velocityDecompose.fig"/>
- </imageobject>
- </mediaobject>
-
- <para>The car's horizontal velocity component will remain
- constant during flight time. The vertical component will give
- rise to an <quote>inverse</quote> free fall until reaching
- maximum height. Afterwards the car will enter a free fall
- until (hopefully!) landing on the second slope.</para>
- </tip>
- </question>
-
- <answer>
- <para>Decomposing the car's velocity into its horizontal and
- vertical components requires trigonometric functions:</para>
-
- <informalequation>
- <m:math display="inline">
- <m:mtable>
- <m:mtr>
- <m:mtd>
- <m:mrow>
- <m:msub>
- <m:mi>v</m:mi>
-
- <m:mi>x</m:mi>
- </m:msub>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mi>v</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mrow>
- <m:mi>cos</m:mi>
-
- <m:mo>â¡</m:mo>
-
- <m:mi>α</m:mi>
- </m:mrow>
- </m:mrow>
- </m:mrow>
- </m:mtd>
- </m:mtr>
-
- <m:mtr>
- <m:mtd>
- <m:mrow>
- <m:msub>
- <m:mi>v</m:mi>
-
- <m:mi>y</m:mi>
- </m:msub>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mi>v</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mrow>
- <m:mi>sin</m:mi>
-
- <m:mo>â¡</m:mo>
-
- <m:mi>α</m:mi>
- </m:mrow>
- </m:mrow>
- </m:mrow>
- </m:mtd>
- </m:mtr>
- </m:mtable>
- </m:math>
- </informalequation>
-
- <para>A bodies' velocity in free fall relates to time by:</para>
-
- <informalequation>
- <m:math display="block">
- <m:mrow>
- <m:mi>v</m:mi>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mi>g</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:mi>t</m:mi>
- </m:mrow>
- </m:mrow>
- </m:math>
- </informalequation>
-
- <para>During a given time a free falling bodies' traveling
- distance will be:</para>
-
- <informalequation>
- <m:math display="block">
- <m:mrow>
- <m:mi>s</m:mi>
-
- <m:mo>=</m:mo>
-
- <m:mrow>
- <m:mfrac>
- <m:mi>1</m:mi>
-
- <m:mi>2</m:mi>
- </m:mfrac>
-
- <m:mo>â¢</m:mo>
-
- <m:mi>g</m:mi>
-
- <m:mo>â¢</m:mo>
-
- <m:msup>
- <m:mi>t</m:mi>
-
- <m:mi>2</m:mi>
- </m:msup>
- </m:mrow>
- </m:mrow>
- </m:math>
- </informalequation>
-
- <para>Assembling these equations leads to:</para>
-
- <annotation role="make">
- <para role="eclipse">Sd1/CarJump/V5</para>
- </annotation>
- </answer>
- </qandaentry>
- </qandadiv>
- </qandaset>
- </section>
- </section>
</chapter>
diff --git a/P/Sd1/CarJump/V1/.gitignore b/P/Sd1/CarJump/V1/.gitignore
deleted file mode 100644
index a1c3ab4d0..000000000
--- a/P/Sd1/CarJump/V1/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-/target/
-/.settings/
-.classpath
-.project
diff --git a/P/Sd1/CarJump/V1/pom.xml b/P/Sd1/CarJump/V1/pom.xml
deleted file mode 100644
index 378058a78..000000000
--- a/P/Sd1/CarJump/V1/pom.xml
+++ /dev/null
@@ -1,48 +0,0 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
- <modelVersion>4.0.0</modelVersion>
-
- <groupId>de.hdm-stuttgart.mi.sd1</groupId>
- <artifactId>carjump</artifactId>
- <version>1.0</version>
- <packaging>jar</packaging>
-
- <name>carjump</name>
- <url>https://freedocs.mi.hdm-stuttgart.de</url>
-
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- </properties>
-
- <dependencies>
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>4.12</version>
- <scope>test</scope>
- </dependency>
-
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-core</artifactId>
- <version>2.9.1</version>
- </dependency>
-
- </dependencies>
-
- <build>
- <plugins>
-
- <plugin>
- <groupId>org.apache.maven.plugins</groupId>
- <artifactId>maven-compiler-plugin</artifactId>
- <version>3.7.0</version>
- <configuration>
- <source>1.8</source>
- <target>1.8</target>
- </configuration>
- </plugin>
-
- </plugins>
- </build>
-
-</project>
diff --git a/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java b/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
deleted file mode 100644
index 1cf16433f..000000000
--- a/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-
-/**
- * Testing the model manually.
- */
-public class Driver {
-
- /**
- * @param args Unused
- */
- public static void main( String[] args ) {
- final CarJump jump = new CarJump(20, 4);
-
- System.out.format("True air speed at airborne time: %3d meters per second.%n", Math.round(jump.getSlopeSpeed()));
- }
-}
diff --git a/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java b/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
deleted file mode 100644
index 1c00c7716..000000000
--- a/P/Sd1/CarJump/V1/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
+++ /dev/null
@@ -1,40 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump.model;
-
-/**
- * Model of a car jump.
- *
- */
-public class CarJump {
-
- /**
- * A model of a car gaining speed and then getting airborne for a jump between
- * two slopes.
- *
- * @param accelHeight See {@link #setAccelHeight(double)}
- * @param slopeHeight See {@link #setSlopeHeight(double)}
- */
- public CarJump(final double accelHeight, final double slopeHeight) {
- // TODO: Implement me!
- }
-
- /**
- * @return The car's speed when leaving the ascending slope.
- */
- public double getSlopeSpeed() {
- return 0; // TODO: Implement me correctly!
- }
-
- /**
- * @param accelHeight The height measured in meters at which the car will start at the very beginning of its journey.
- */
- public void setAccelHeight(double accelHeight) {
- // TODO: Implement me!
- }
-
- /**
- * @param slopeHeight The slope's tip height above ground level measured in meters.
- */
- public void setSlopeHeight(double slopeHeight) {
- // TODO: Implement me!
- }
-}
\ No newline at end of file
diff --git a/P/Sd1/CarJump/V1/src/main/resources/log4j2.xml b/P/Sd1/CarJump/V1/src/main/resources/log4j2.xml
deleted file mode 100644
index 67f853751..000000000
--- a/P/Sd1/CarJump/V1/src/main/resources/log4j2.xml
+++ /dev/null
@@ -1,21 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Configuration>
- <Appenders>
- <File name="A1" fileName="A1.log" append="false">
- <PatternLayout pattern="%t %-5p %c{2} - %m%n"/>
- </File>
- <Console name="STDOUT" target="SYSTEM_OUT">
- <PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
- </Console>
- </Appenders>
- <Loggers>
-
- <!-- You my want to define class or package level per-logger rules -->
- <Logger name="de.hdm_stuttgart.mi.sd1.carjump.App" level="debug">
- <AppenderRef ref="A1"/>
- </Logger>
- <Root level="info">
- <AppenderRef ref="STDOUT"/>
- </Root>
- </Loggers>
-</Configuration>
\ No newline at end of file
diff --git a/P/Sd1/CarJump/V2/.gitignore b/P/Sd1/CarJump/V2/.gitignore
deleted file mode 100644
index a1c3ab4d0..000000000
--- a/P/Sd1/CarJump/V2/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-/target/
-/.settings/
-.classpath
-.project
diff --git a/P/Sd1/CarJump/V2/pom.xml b/P/Sd1/CarJump/V2/pom.xml
deleted file mode 100644
index a30be7f4f..000000000
--- a/P/Sd1/CarJump/V2/pom.xml
+++ /dev/null
@@ -1,48 +0,0 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
- <modelVersion>4.0.0</modelVersion>
-
- <groupId>de.hdm-stuttgart.mi.sd1</groupId>
- <artifactId>carjump</artifactId>
- <version>2.0</version>
- <packaging>jar</packaging>
-
- <name>carjump</name>
- <url>https://freedocs.mi.hdm-stuttgart.de</url>
-
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- </properties>
-
- <dependencies>
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>4.12</version>
- <scope>test</scope>
- </dependency>
-
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-core</artifactId>
- <version>2.9.1</version>
- </dependency>
-
- </dependencies>
-
- <build>
- <plugins>
-
- <plugin>
- <groupId>org.apache.maven.plugins</groupId>
- <artifactId>maven-compiler-plugin</artifactId>
- <version>3.7.0</version>
- <configuration>
- <source>1.8</source>
- <target>1.8</target>
- </configuration>
- </plugin>
-
- </plugins>
- </build>
-
-</project>
diff --git a/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java b/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
deleted file mode 100644
index 52dae66fa..000000000
--- a/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-
-/**
- *
- */
-public class Driver {
-
- /**
- * @param args Unused
- */
- public static void main( String[] args ) {
- final CarJump jump = new CarJump(20, 4);
-
- System.out.format("True air speed at airborne time: %5.2f meters per second.%n", Math.round(10 *jump.getSlopeSpeed()) / 10.);
- }
-}
diff --git a/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java b/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
deleted file mode 100644
index 5b00fdb07..000000000
--- a/P/Sd1/CarJump/V2/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
+++ /dev/null
@@ -1,74 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump.model;
-
-/**
- * Model of a car jump.
- *
- */
-public class CarJump {
-
- // Physical constant describing a fall's acceleration
- // due to gravity.
- private static final double gravitationalAcceleration = 9.81;
-
- // Model parameters
- private double
- accelHeight,
- slopeHeight;
-
- // derived parameters
- double
- slopeSpeed;
-
- /**
- * Internal method to be called at end of object construction
- * and after changing any model parameter. Re-calculates
- * derived parameters, see above.
- */
- private void calculateDerivedParameters() {
- slopeSpeed = Math.sqrt(2 * gravitationalAcceleration * (accelHeight - slopeHeight));
- }
-
- /**
- * A model of a car gaining speed and then getting airborne for a jump between
- * two slopes.
- *
- * @param accelHeight See {@link #setAccelHeight(double)}
- * @param slopeHeight See {@link #setSlopeHeight(double)}
- */
- public CarJump(final double accelHeight, final double slopeHeight) {
- // We assign attribute values since calling i.e. setAccelHeight(...) would trigger the invocation
- // of calculateDerivedParameters(). But this invocation must be deferred till our object
- // has been fully initialized.
- //
- this.accelHeight = accelHeight;
- this.slopeHeight = slopeHeight;
- calculateDerivedParameters();
- }
-
- /**
- * @return The car's speed when leaving the ascending slope.
- */
- public double getSlopeSpeed() {
- return slopeSpeed;
- }
-
- /**
- * @param accelHeight The height measured in meters at which the car will start at the very beginning of its journey.
- */
- public void setAccelHeight(double accelHeight) {
- if (accelHeight != this.accelHeight) { // Only assign and re-calculate if required
- this.accelHeight = accelHeight;
- calculateDerivedParameters();
- }
- }
-
- /**
- * @param slopeHeight The slope's tip height above ground level measured in meters.
- */
- public void setSlopeHeight(double slopeHeight) {
- if (slopeHeight != this.slopeHeight) {// Only assign and re-calculate if required
- this.slopeHeight = slopeHeight;
- calculateDerivedParameters();
- }
- }
-}
\ No newline at end of file
diff --git a/P/Sd1/CarJump/V2/src/main/resources/log4j2.xml b/P/Sd1/CarJump/V2/src/main/resources/log4j2.xml
deleted file mode 100644
index 67f853751..000000000
--- a/P/Sd1/CarJump/V2/src/main/resources/log4j2.xml
+++ /dev/null
@@ -1,21 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<Configuration>
- <Appenders>
- <File name="A1" fileName="A1.log" append="false">
- <PatternLayout pattern="%t %-5p %c{2} - %m%n"/>
- </File>
- <Console name="STDOUT" target="SYSTEM_OUT">
- <PatternLayout pattern="%d %-5p [%t] %C{2} (%F:%L) - %m%n"/>
- </Console>
- </Appenders>
- <Loggers>
-
- <!-- You my want to define class or package level per-logger rules -->
- <Logger name="de.hdm_stuttgart.mi.sd1.carjump.App" level="debug">
- <AppenderRef ref="A1"/>
- </Logger>
- <Root level="info">
- <AppenderRef ref="STDOUT"/>
- </Root>
- </Loggers>
-</Configuration>
\ No newline at end of file
diff --git a/P/Sd1/CarJump/V2/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java b/P/Sd1/CarJump/V2/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
deleted file mode 100644
index 661d3a30a..000000000
--- a/P/Sd1/CarJump/V2/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-/**
- * Unit test for car jump model.
- */
-public class ModelTest {
- /**
- * Checking approximate velocity value.
- */
- @Test
- public void testAirborneVelocity() {
-
- final CarJump jump = new CarJump(20, 4);
-
- Assert.assertEquals(17.71, jump.getSlopeSpeed(), 1.E-2);
- }
-}
diff --git a/P/Sd1/CarJump/V5/.gitignore b/P/Sd1/CarJump/V5/.gitignore
deleted file mode 100644
index a1c3ab4d0..000000000
--- a/P/Sd1/CarJump/V5/.gitignore
+++ /dev/null
@@ -1,4 +0,0 @@
-/target/
-/.settings/
-.classpath
-.project
diff --git a/P/Sd1/CarJump/V5/pom.xml b/P/Sd1/CarJump/V5/pom.xml
deleted file mode 100644
index e9b0187b0..000000000
--- a/P/Sd1/CarJump/V5/pom.xml
+++ /dev/null
@@ -1,48 +0,0 @@
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
- <modelVersion>4.0.0</modelVersion>
-
- <groupId>de.hdm-stuttgart.mi.sd1</groupId>
- <artifactId>carjump</artifactId>
- <version>5.0</version>
- <packaging>jar</packaging>
-
- <name>carjump</name>
- <url>https://freedocs.mi.hdm-stuttgart.de</url>
-
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- </properties>
-
- <dependencies>
- <dependency>
- <groupId>junit</groupId>
- <artifactId>junit</artifactId>
- <version>4.12</version>
- <scope>test</scope>
- </dependency>
-
- <dependency>
- <groupId>org.apache.logging.log4j</groupId>
- <artifactId>log4j-core</artifactId>
- <version>2.9.1</version>
- </dependency>
-
- </dependencies>
-
- <build>
- <plugins>
-
- <plugin>
- <groupId>org.apache.maven.plugins</groupId>
- <artifactId>maven-compiler-plugin</artifactId>
- <version>3.7.0</version>
- <configuration>
- <source>1.8</source>
- <target>1.8</target>
- </configuration>
- </plugin>
-
- </plugins>
- </build>
-
-</project>
diff --git a/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java b/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
deleted file mode 100644
index ecb167435..000000000
--- a/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/Driver.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-/**
- * Manually testing car jump model.
- */
-public class Driver {
-
- /**
- * @param args Unused
- */
- public static void main( String[] args ) {
- final CarJump jump = new CarJump(20, 45, 4);
-
- System.out.format("Jump distance %3d meters.%n", Math.round(jump.getJumpDistance()));
- System.out.format("Jump height: %d meters. %n", Math.round(jump.getJumpHeight()));
- }
-}
diff --git a/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java b/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
deleted file mode 100644
index e9c90e81d..000000000
--- a/P/Sd1/CarJump/V5/src/main/java/de/hdm_stuttgart/mi/sd1/carjump/model/CarJump.java
+++ /dev/null
@@ -1,110 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump.model;
-
-public class CarJump {
-
- // Physical constant describing a fall's acceleration
- // due to gravity.
- private static final double gravitationalAcceleration = 9.81;
-
- // Model parameters
- private double
- accelHeight,
- slopeAngle,
- slopeHeight;
-
- // derived parameters
- double
- slopeSpeed,
- jumpHeight,
- jumpDistance;
-
- /**
- * Internal method to be called at end of object construction
- * and after changing any model parameter. Re-calculates
- * derived parameters, see above.
- */
- private void calculateDerivedParameters() {
-
- slopeSpeed = Math.sqrt(2 * gravitationalAcceleration * (accelHeight - slopeHeight));
-
- final double slopeAngleInRadians = slopeAngle / 180 * Math.PI;
-
- jumpDistance = Math.sin(2 * slopeAngleInRadians) * slopeSpeed * slopeSpeed /
- gravitationalAcceleration;
-
- final double sine = Math.sin(slopeAngleInRadians);
- jumpHeight = slopeHeight + sine * sine * slopeSpeed * slopeSpeed / 2 / gravitationalAcceleration;
- }
-
- /**
- * A model of a car gaining speed and then getting airborne for a jump between
- * two slopes.
- *
- * @param accelHeight See {@link #setAccelHeight(double)}
- * @param slopeAngle See {@link #setSlopeAngle(double)}
- * @param slopeHeight See {@link #setSlopeHeight(double)}
- */
- public CarJump(final double accelHeight, final double slopeAngle, final double slopeHeight) {
- // We assign attribute values since calling i.e. setAccelHeight(...) would trigger the invocation
- // of calculateDerivedParameters(). But this invocation must be deferred till our object
- // has been fully initialized.
- //
- this.accelHeight = accelHeight;
- this.slopeAngle = slopeAngle;
- this.slopeHeight = slopeHeight;
- calculateDerivedParameters();
- }
-
- /**
- * @return The car's maximum height above ground level while being
- * airborne.
- */
- public double getJumpHeight() {
- return jumpHeight;
- }
-
- /**
- * @return
- */
- public double getJumpDistance() {
- return jumpDistance;
- }
-
- /**
- * @return
- */
- public double getSlopeSpeed() {
- return slopeSpeed;
- }
-
- /**
- * @param accelHeight The height measured in meters at which the car will start at the very beginning of its journey.
- */
- public void setAccelHeight(double accelHeight) {
- if (accelHeight != this.accelHeight) { // Only assign and re-calculate if required
- this.accelHeight = accelHeight;
- calculateDerivedParameters();
- }
- }
-
- /**
- * @param slopeAngle The slope's angle measured in degrees (0-360).
- */
- public void setSlopeAngle(double slopeAngle) {
- if (slopeAngle != this.slopeAngle) { // Only assign and re-calculate if required
- this.slopeAngle = slopeAngle;
- calculateDerivedParameters();
- }
- }
-
-
- /**
- * @param slopeHeight The slope's tip height above ground level measured in meters.
- */
- public void setSlopeHeight(double slopeHeight) {
- if (slopeHeight != this.slopeHeight) {// Only assign and re-calculate if required
- this.slopeHeight = slopeHeight;
- calculateDerivedParameters();
- }
- }
-}
\ No newline at end of file
diff --git a/P/Sd1/CarJump/V5/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java b/P/Sd1/CarJump/V5/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
deleted file mode 100644
index 7414e7409..000000000
--- a/P/Sd1/CarJump/V5/src/test/java/de/hdm_stuttgart/mi/sd1/carjump/ModelTest.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package de.hdm_stuttgart.mi.sd1.carjump;
-
-import org.junit.Assert;
-import org.junit.Test;
-
-import de.hdm_stuttgart.mi.sd1.carjump.model.CarJump;
-
-/**
- * Unit test for car jump model.
- */
-public class ModelTest {
- /**
- * Checking approximate velocity value.
- */
- @Test
- public void testAirborneVelocity() {
-
- final CarJump jump = new CarJump(20, 45, 4);
-
- Assert.assertEquals(17.71, jump.getSlopeSpeed(), 1.E-2);
- }
-}
diff --git a/P/Sd1/CoreClasses/StringMask/.gitignore b/P/Sd1/CoreClasses/StringMask/.gitignore
new file mode 100644
index 000000000..1a547d140
--- /dev/null
+++ b/P/Sd1/CoreClasses/StringMask/.gitignore
@@ -0,0 +1,54 @@
+/target/
+/.settings/
+.classpath
+.project
+
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and Webstorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff:
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/dictionaries
+
+# Sensitive or high-churn files:
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.xml
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+
+# Gradle:
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# CMake
+cmake-build-debug/
+
+# Mongo Explorer plugin:
+.idea/**/mongoSettings.xml
+
+## File-based project format:
+*.iws
+
+## Plugin-specific files:
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Cursive Clojure plugin
+.idea/replstate.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
\ No newline at end of file
diff --git a/P/Sd1/CoreClasses/StringMask/pom.xml b/P/Sd1/CoreClasses/StringMask/pom.xml
new file mode 100644
index 000000000..ec09c3937
--- /dev/null
+++ b/P/Sd1/CoreClasses/StringMask/pom.xml
@@ -0,0 +1,80 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+ <modelVersion>4.0.0</modelVersion>
+
+ <groupId>de.hdm_stuttgart.mi.sd1</groupId>
+ <artifactId>stringmask</artifactId>
+ <version>1.0-SNAPSHOT</version>
+ <packaging>jar</packaging>
+
+ <name>stringmask</name>
+
+ <url>https://freedocs.mi.hdm-stuttgart.de/sd1SectToolsOfTheTrade2.html</url>
+
+ <properties>
+ <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+ </properties>
+
+ <dependencies>
+ <dependency>
+ <groupId>junit</groupId>
+ <artifactId>junit</artifactId>
+ <version>4.12</version>
+ <scope>test</scope>
+ </dependency>
+
+ <dependency>
+ <groupId>org.apache.logging.log4j</groupId>
+ <artifactId>log4j-core</artifactId>
+ <version>2.9.1</version>
+ </dependency>
+
+ </dependencies>
+
+ <build>
+ <plugins>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-compiler-plugin</artifactId>
+ <version>3.7.0</version>
+ <configuration>
+ <source>1.8</source>
+ <target>1.8</target>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-javadoc-plugin</artifactId>
+ <version>2.10.4</version>
+ <configuration />
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-shade-plugin</artifactId>
+ <version>3.1.0</version>
+ <configuration>
+ <transformers>
+ <transformer
+ implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+ <manifestEntries>
+ <Main-Class>de.hdm_stuttgart.mi.sd1.Mask</Main-Class>
+ </manifestEntries>
+ </transformer>
+ </transformers>
+ </configuration>
+ <executions>
+ <execution>
+ <phase>package</phase>
+ <goals>
+ <goal>shade</goal>
+ </goals>
+ </execution>
+ </executions>
+ </plugin>
+
+ </plugins>
+ </build>
+</project>
diff --git a/P/Sd1/CoreClasses/StringMask/src/main/java/de/hdm_stuttgart/mi/sd1/Mask.java b/P/Sd1/CoreClasses/StringMask/src/main/java/de/hdm_stuttgart/mi/sd1/Mask.java
new file mode 100644
index 000000000..99814ef5b
--- /dev/null
+++ b/P/Sd1/CoreClasses/StringMask/src/main/java/de/hdm_stuttgart/mi/sd1/Mask.java
@@ -0,0 +1,55 @@
+package de.hdm_stuttgart.mi.sd1;
+
+import java.util.Arrays;
+
+public class Mask {
+
+ /**
+ * Number of character positions being visible when masking a string. See {@link #mask(String)}
+ * for details.
+ */
+ static public final int VISIBLE_POSITIONS = 4;
+
+ /**
+ * <p>Mask all but {@link #VISIBLE_POSITIONS} positions of a given string by '#' characters. Examples:</p>
+ *
+ * <ul>
+ * <li> "You" --> "You" </li>
+ * <li> "Secret" --> "##cret" </li>
+ * <li> "Ultimate test" --> "#########test" </li>
+ * </ul>
+ *
+ * @param s The input string to be masked.
+ * @return The masked string or null in case of null input string
+ */
+ public static String mask(final String s) {
+ if (null == s || s.length() <= VISIBLE_POSITIONS) {
+ return s;
+ } else {
+ final int maskLength = s.length() - VISIBLE_POSITIONS;
+
+ final StringBuffer result = new StringBuffer();
+ for (int i = 0; i < maskLength; i++) {
+ result.append('#');
+ }
+ return result.append(s.substring(maskLength)).toString();
+ }
+ }
+
+ /**
+ * Alternate implementation using yet not covered array topic.
+ *
+ * @param s The input string to be masked.
+ * @return The masked string or null in case of null input string
+ */
+ public static String mask2(final String s) {
+ if (null == s || s.length() <= VISIBLE_POSITIONS) {
+ return s;
+ } else {
+ final int maskLength = s.length() - VISIBLE_POSITIONS;
+ final char[] mask = new char[maskLength];
+ Arrays.fill(mask, '#');
+ return new String(mask).concat(s.substring(maskLength));
+ }
+ }
+}
diff --git a/P/Sd1/CarJump/V5/src/main/resources/log4j2.xml b/P/Sd1/CoreClasses/StringMask/src/main/resources/log4j2.xml
similarity index 89%
rename from P/Sd1/CarJump/V5/src/main/resources/log4j2.xml
rename to P/Sd1/CoreClasses/StringMask/src/main/resources/log4j2.xml
index 67f853751..271655702 100644
--- a/P/Sd1/CarJump/V5/src/main/resources/log4j2.xml
+++ b/P/Sd1/CoreClasses/StringMask/src/main/resources/log4j2.xml
@@ -11,7 +11,7 @@
<Loggers>
<!-- You my want to define class or package level per-logger rules -->
- <Logger name="de.hdm_stuttgart.mi.sd1.carjump.App" level="debug">
+ <Logger name="de.hdm_stuttgart.mi.sd1.Mask" level="debug">
<AppenderRef ref="A1"/>
</Logger>
<Root level="info">
diff --git a/P/Sd1/CoreClasses/StringMask/src/test/java/de/hdm_stuttgart/mi/sd1/MaskTest.java b/P/Sd1/CoreClasses/StringMask/src/test/java/de/hdm_stuttgart/mi/sd1/MaskTest.java
new file mode 100644
index 000000000..03dd1993c
--- /dev/null
+++ b/P/Sd1/CoreClasses/StringMask/src/test/java/de/hdm_stuttgart/mi/sd1/MaskTest.java
@@ -0,0 +1,40 @@
+package de.hdm_stuttgart.mi.sd1;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Unit test for simple Mask.
+ */
+public class MaskTest {
+ /**
+ * null input
+ */
+ @Test
+ public void testNullInput() {
+ Assert.assertEquals( null, Mask.mask(null) );
+ }
+
+ /**
+ * 4 or less characters should be left untouched.
+ */
+ @Test
+ public void testBelowLimit() {
+ Assert.assertEquals( "", Mask.mask("") );
+ Assert.assertEquals( "1", Mask.mask("1") );
+ Assert.assertEquals( "12", Mask.mask("12") );
+ Assert.assertEquals( "123", Mask.mask("123") );
+ Assert.assertEquals( "1234", Mask.mask("1234") );
+ }
+ /**
+ * More than 4 characters require masking.
+ */
+ @Test
+ public void testAboveLimit() {
+ Assert.assertEquals( "#2345", Mask.mask("12345") );
+ Assert.assertEquals( "##3456", Mask.mask("123456") );
+ Assert.assertEquals( "###4567", Mask.mask("1234567") );
+ Assert.assertEquals( "####5678", Mask.mask("12345678") );
+ Assert.assertEquals( "#####6789", Mask.mask("123456789") );
+ }
+}
\ No newline at end of file
diff --git a/P/pom.xml b/P/pom.xml
index 96767e5b1..d99f137b9 100644
--- a/P/pom.xml
+++ b/P/pom.xml
@@ -38,6 +38,7 @@
<module>Sd1/Array/arraycalcExercise</module>
<module>Sd1/Array/integerStoreStat</module>
<module>Sd1/Array/marking</module>
+ <module>Sd1/CoreClasses/StringMask</module>
<module>Sd1/Euler/11/largestproductingrid</module>
<module>Sd1/Wc/readFile</module>
<module>Sd1/Wc/wc</module>
--
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