categories now use lists instead of sets. able to remove categories by name

src/main/java/mi/hdm/recipes/Categories.java

 package mi.hdm.recipes;
 
-import java.util.Set;
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
 
 public class Categories {
+    private static final Categories instance = new Categories();
+    private static final Logger log = LogManager.getLogger(Categories.class);
+
+    private final List<Category> allCategories;
+
+    private Categories() {
+        allCategories = new ArrayList<>();
+    }
 
-    private Set<Category> allCategories;
+    public static Categories getInstance() {
+        return instance;
+    }
 
+    /**
+     * Adds a category if neither the given name nor the color code have been used in a category before.
+     * @param name Name for the category that is to be added
+     * @param colourCode Color code for the category that is to be added
+     * @return True if the category has been added (meaning no equal category existed before), otherwise false.
+     */
     public boolean addCategory(String name, int colourCode){
-        return allCategories.add(new Category(name, colourCode));
+        Category c = new Category(name, colourCode);
+        if(allCategories.contains(c)) {
+            log.debug("Category: {} not added", c.getName());
+            return false;
+        } else {
+            allCategories.add(c);
+            log.debug("Category {} added successfully.", c.getName());
+            return true;
+        }
     }
 
     public boolean deleteCategory(Category c) {
         return allCategories.remove(c);
     }
 
-    public void removeCategory(String name) {}
+    public boolean deleteCategory(String name) {
+        Category c = getCategoryByName(name).orElseThrow();
+        return allCategories.remove(c);
+    }
 
-    public Set<Category> getAllCategories(){
+    public List<Category> getAllCategories(){
         return allCategories;
     }
+
+    public void clearCategories() {
+        allCategories.clear();
+    }
+
+    private Optional<Category> getCategoryByName(String name) {
+        return allCategories.stream()
+                .filter(c -> c.getName().equals(name))
+                .findFirst();
+    }
 }

src/main/java/mi/hdm/recipes/Category.java

@@ -20,7 +20,8 @@ public class Category {
         return name;
     }
 
-    @Override public boolean equals(Object o){
+    @Override
+    public boolean equals(Object o){
         if (o instanceof Category) {
             Category c = (Category) o;
             return this.name.equals(c.getName()) || this.colourCode == c.getColourCode();
@@ -28,4 +29,9 @@ public class Category {
         return false;
     }
 
+    @Override
+    public String toString() {
+        return String.format("Category %s with color code %d", name, colourCode);
+    }
+
 }

src/main/java/mi/hdm/recipes/RecipeManager.java

@@ -48,11 +48,7 @@ public class RecipeManager {
     }
 
     private Optional<Recipe> getRecipeByName(String name) {
-        /*boolean b = recipes.stream()
-                .anyMatch(r -> r.getName().equals(name));
-        if(!b) return Optional.empty();*/
-
-        for (final Recipe r: recipes) {
+        for (final Recipe r : recipes) {
             if (name.equals(r.getName())) {
                 return Optional.of(r);
             }

src/main/resources/log4j2.xml

@@ -14,7 +14,7 @@
         <Logger name="mi.hdm.GuiDriver" level="debug">
             <AppenderRef ref="A1"/>
         </Logger>
-        <Root level="info">
+        <Root level="debug">
             <AppenderRef ref="STDOUT"/>
         </Root>
     </Loggers>

src/test/java/mi/hdm/recipes/CategoryTest.java

@@ -7,10 +7,11 @@ import org.junit.Test;
 import static org.junit.Assert.*;
 
 public class CategoryTest {
-    Categories underTest = new Categories();
+    Categories underTest = Categories.getInstance();
 
     @Test
     public void testEquals() {
+        underTest.clearCategories();
         Category c1 = new Category("Abend", 0x00FF00);
         Category c2 = new Category("LEcker", 0x13);
         Category c3 = new Category("ew", 0x13);
@@ -23,14 +24,41 @@ public class CategoryTest {
 
     @Test
     public void shouldNotBeAbleToAddIdenticalName() {
+        underTest.clearCategories();
         underTest.addCategory("Mittag", 0x100000);
-        underTest.addCategory("Mittag", 0x100000);
+        underTest.addCategory("Mittag", 0x100040);
+
+        Assert.assertEquals(1, underTest.getAllCategories().size());
+    }
+
+    @Test
+    public void shouldNotBeAbleToAddIdenticalCode() {
+        underTest.clearCategories();
+        underTest.addCategory("Morgen", 0x100040);
+        underTest.addCategory("Mittag", 0x100040);
+
         Assert.assertEquals(1, underTest.getAllCategories().size());
     }
 
     @Test
     public void shouldBeAbleToAddCategory() {
+        underTest.clearCategories();
         underTest.addCategory("Morgen", 0x100000);
+        underTest.addCategory("Abend", 0x100010);
+
         Assert.assertEquals(2, underTest.getAllCategories().size());
     }
+
+    @Test
+    public void canRemoveCategoryByName() {
+        //given
+        underTest.clearCategories();
+        underTest.addCategory("Jan ist cool", 0xFF0000);
+
+        //when
+        underTest.deleteCategory("Jan ist cool");
+
+        //expect
+        assertEquals(0, underTest.getAllCategories().size());
+    }
 }