From 0ee00133d1772f3f4c47d6d89967bc2cf720c132 Mon Sep 17 00:00:00 2001
From: Martin Goik <goik@hdm-stuttgart.de>
Date: Tue, 3 Nov 2015 17:36:48 +0100
Subject: [PATCH] New persistence handler
---
P/Sda1/persistencehandler/.gitignore | 5 +
P/Sda1/persistencehandler/pom.xml | 31 ++++
.../mi/sda1/persistencehandler/DbProps.java | 22 +++
.../PersistenceHandler.java | 167 ++++++++++++++++++
.../persistencehandler/database.properties | 3 +
.../src/main/resources/log4j2.xml | 21 +++
.../src/main/resources/schema.sql | 6 +
.../sda1/persistencehandler/PersistTest.java | 12 ++
8 files changed, 267 insertions(+)
create mode 100644 P/Sda1/persistencehandler/.gitignore
create mode 100644 P/Sda1/persistencehandler/pom.xml
create mode 100644 P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/DbProps.java
create mode 100644 P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistenceHandler.java
create mode 100644 P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/database.properties
create mode 100644 P/Sda1/persistencehandler/src/main/resources/log4j2.xml
create mode 100644 P/Sda1/persistencehandler/src/main/resources/schema.sql
create mode 100644 P/Sda1/persistencehandler/src/test/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistTest.java
diff --git a/P/Sda1/persistencehandler/.gitignore b/P/Sda1/persistencehandler/.gitignore
new file mode 100644
index 000000000..660be2a5f
--- /dev/null
+++ b/P/Sda1/persistencehandler/.gitignore
@@ -0,0 +1,5 @@
+.project
+.classpath
+/.settings/
+/target/
+A1.log
\ No newline at end of file
diff --git a/P/Sda1/persistencehandler/pom.xml b/P/Sda1/persistencehandler/pom.xml
new file mode 100644
index 000000000..8511f6410
--- /dev/null
+++ b/P/Sda1/persistencehandler/pom.xml
@@ -0,0 +1,31 @@
+<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>
+
+ <parent>
+ <groupId>de.hdm-stuttgart.mi</groupId>
+ <artifactId>lecturenotes-pom</artifactId>
+ <version>1.0</version>
+
+ <relativePath>../../pom.xml</relativePath>
+ </parent>
+
+ <groupId>de.hdm-stuttgart.mi.sda1</groupId>
+ <artifactId>persistencehandler</artifactId>
+ <version>0.8</version>
+ <packaging>jar</packaging>
+
+ <name>Persistencehandler</name>
+ <url>http://www.mi.hdm-stuttgart.de/freedocs</url>
+
+ <dependencies>
+
+ <dependency>
+ <groupId>mysql</groupId>
+ <artifactId>mysql-connector-java</artifactId>
+ <version>${mysql.mysql-connector-java.version}</version>
+ </dependency>
+
+ </dependencies>
+
+</project>
diff --git a/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/DbProps.java b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/DbProps.java
new file mode 100644
index 000000000..c5ad2bc9c
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/DbProps.java
@@ -0,0 +1,22 @@
+package de.hdm_stuttgart.mi.sda1.persistencehandler;
+
+import java.util.MissingResourceException;
+import java.util.ResourceBundle;
+
+public class DbProps {
+ private static final String BUNDLE_NAME = "sda.jdbc.intro.v1.database";
+
+ private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle
+ .getBundle(BUNDLE_NAME);
+
+ private DbProps() {
+ }
+
+ public static String getString(String key) {
+ try {
+ return RESOURCE_BUNDLE.getString(key);
+ } catch (MissingResourceException e) {
+ return '!' + key + '!';
+ }
+ }
+}
diff --git a/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistenceHandler.java b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistenceHandler.java
new file mode 100644
index 000000000..f436337b3
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistenceHandler.java
@@ -0,0 +1,167 @@
+package de.hdm_stuttgart.mi.sda1.persistencehandler;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+/**
+ * Handle database communication. There are two
+ * distinct internal states <strong>disconnected</strong> and <strong>connected</strong>, see
+ * {@link #isConnected()}. These two states may be toggled by invoking
+ * {@link #connect()} and {@link #disconnect()} respectively.
+ *
+ * The following snippet illustrates the intended usage:
+ * <pre> public static void main(String[] args) {
+ final PersistenceHandler ph = new PersistenceHandler();
+ if (ph.connect()) {
+ if (!ph.add("Jim", "jim@foo.com")) {
+ System.err.println("Insert Error:" + ph.getErrorMessage());
+ }
+ } else {
+ System.err.println("Connect error:" + ph.getErrorMessage());
+ }
+ }</pre>
+ *
+ * @author goik
+ */
+public class PersistenceHandler {
+
+ Connection conn = null;
+ Statement stmt = null;
+
+ String errorMessage = null;
+
+ /**
+ * New instances are in <strong>disconnected</strong> state. See {@link #isConnected()}
+ */
+ public PersistenceHandler() {/* only present here to supply javadoc comment */}
+
+ /**
+ * Inserting a (name, email) record into the database server. In case of
+ * errors corresponding messages may subsequently be retrieved by calling
+ * {@link #getErrorMessage()}.
+ *
+ * <dl>
+ * <dt><b>Precondition:</b></dt>
+ * <dd>must be in <strong>connected</strong> state, see {@link #isConnected()}</dd>
+ * </dl>
+ *
+ * @param name A person's name
+ * @param email A person's email address
+ *
+ * @return true if the current data record has been successfully inserted
+ * into the database server. false in case of error(s).
+ */
+ public boolean add(final String name, final String email){
+ final String sql = "INSERT INTO Person VALUES('" + name + "', '" +
+ email + "')";
+ try {
+ stmt.executeUpdate(sql);
+ return true;
+ } catch (SQLException e) {
+ errorMessage = "Unable to execute '" + sql + "': '" + e.getMessage() + "'";
+ return false;
+ }
+ }
+
+ /**
+ * Retrieving error messages in case a call to {@link #add(String, String)},
+ * {@link #connect()}, or {@link #disconnect()} yields an error.
+ *
+ * @return the error explanation corresponding to the latest failed
+ * operation, null if no error yet occurred.
+ */
+ public String getErrorMessage() {
+ return errorMessage;
+ }
+
+ /**
+ * Open a connection to a database server.
+ *
+ * <dl>
+ * <dt><b>Precondition:</b></dt>
+ * <dd>must be in <strong>disconnected</strong> state, see {@link #isConnected()}</dd>
+ *
+ * <dt><b>Precondition:</b></dt>
+ * <dd>The following properties must be set:
+ * <pre>PersistenceHandler.jdbcUrl=jdbc:mysql://localhost:3306/hdm
+PersistenceHandler.password=XYZ
+PersistenceHandler.username=foo</pre>
+ * </dd>
+ * </dl>
+ *
+ * @return true if connecting was successful
+ */
+ public boolean connect () {
+ try {
+ conn = DriverManager.getConnection(
+ DbProps.getString("PersistenceHandler.jdbcUrl"),
+ DbProps.getString("PersistenceHandler.username"),
+ DbProps.getString("PersistenceHandler.password"));
+ try {
+ stmt = conn.createStatement();
+ return true;
+ } catch (SQLException e) {
+ errorMessage = "Connection opened but Statement creation failed:\"" + e.getMessage() + "\".";
+ try {
+ conn.close();
+ } catch (SQLException ee) {
+ errorMessage += "Closing connection failed:\"" + e.getMessage() + "\".";
+ }
+ conn = null;
+ }
+
+ } catch (SQLException e) {
+ errorMessage = "Unable to open connection:\"" + e.getMessage() + "\".";
+ }
+ return false;
+ }
+
+ /**
+ * Close a connection to a database server and clean up JDBC related resources
+ *
+ * Error messages in case of failure may subsequently be retrieved by
+ * calling {@link #getErrorMessage()}.
+ *
+ * <dl>
+ * <dt><b>Precondition:</b></dt>
+ * <dd>must be in <strong>connected</strong> state, see {@link #isConnected()}</dd>
+ * </dl>
+ *
+ * @return true if disconnecting was successful, false in case error(s) occur.
+ */
+ public boolean disconnect() {
+ boolean resultStatus = true;
+ final StringBuffer messageCollector = new StringBuffer();
+ try {
+ stmt.close();
+ } catch (SQLException e) {
+ resultStatus = false;
+ messageCollector.append("Unable to close Statement:\"" + e.getMessage() + "\".");
+ }
+ stmt = null;
+ try {
+ conn.close();
+ } catch (SQLException e) {
+ resultStatus = false;
+ messageCollector.append("Unable to close connection:\"" + e.getMessage() + "\".");
+ }
+ conn = null;
+ if (!resultStatus) {
+ errorMessage = messageCollector.toString();
+ }
+ return resultStatus;
+ }
+
+ /**
+ * An instance can either be in <strong>connected</strong> or <strong>disconnected</strong> state. The
+ * state can be toggled by invoking {@link #connect()} or
+ * {@link #disconnect()} respectively.
+ *
+ * @return true if connected, false otherwise
+ */
+ public boolean isConnected() {
+ return null != conn;
+ }
+}
\ No newline at end of file
diff --git a/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/database.properties b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/database.properties
new file mode 100644
index 000000000..cce27557f
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/main/java/de/hdm_stuttgart/mi/sda1/persistencehandler/database.properties
@@ -0,0 +1,3 @@
+PersistenceHandler.jdbcUrl=jdbc:mysql://localhost:3306/hdm
+PersistenceHandler.username=hdmuser
+PersistenceHandler.password=XYZ
diff --git a/P/Sda1/persistencehandler/src/main/resources/log4j2.xml b/P/Sda1/persistencehandler/src/main/resources/log4j2.xml
new file mode 100644
index 000000000..eda4f3b0d
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/main/resources/log4j2.xml
@@ -0,0 +1,21 @@
+<?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="%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.sda1.catalog2sax.App" level="debug">
+ <AppenderRef ref="A1"/>
+ </Logger>
+ <Root level="debug">
+ <AppenderRef ref="STDOUT"/>
+ </Root>
+ </Loggers>
+</Configuration>
\ No newline at end of file
diff --git a/P/Sda1/persistencehandler/src/main/resources/schema.sql b/P/Sda1/persistencehandler/src/main/resources/schema.sql
new file mode 100644
index 000000000..2821a2e90
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/main/resources/schema.sql
@@ -0,0 +1,6 @@
+DROP TABLE IF EXISTS Person;
+
+CREATE TABLE Person (
+ name char(80)
+ ,email CHAR(20) UNIQUE
+);
diff --git a/P/Sda1/persistencehandler/src/test/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistTest.java b/P/Sda1/persistencehandler/src/test/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistTest.java
new file mode 100644
index 000000000..1eee7ee94
--- /dev/null
+++ b/P/Sda1/persistencehandler/src/test/java/de/hdm_stuttgart/mi/sda1/persistencehandler/PersistTest.java
@@ -0,0 +1,12 @@
+package de.hdm_stuttgart.mi.sda1.persistencehandler;
+
+/**
+ * Testing persisting objects.
+ *
+ */
+public class PersistTest {
+
+
+
+
+}
--
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