Implement automatic sorting for MemoryHabitList

app/src/main/java/org/isoron/uhabits/models/HabitList.java

@@ -33,6 +33,13 @@ import java.util.*;
  */
 public abstract class HabitList implements Iterable<Habit>
 {
+    public enum Order
+    {
+        BY_NAME,
+        BY_COLOR,
+        BY_POSITION
+    }
+
     private ModelObservable observable;
 
     @NonNull
@@ -157,6 +164,13 @@ public abstract class HabitList implements Iterable<Habit>
         }
     }
 
+    /**
+     * Changes the order of the elements on the list.
+     *
+     * @param order the new order criterea
+     */
+    public abstract void setOrder(Order order);
+
     /**
      * Returns the number of habits in this list.
      *

app/src/main/java/org/isoron/uhabits/models/memory/MemoryHabitList.java

@@ -25,6 +25,8 @@ import org.isoron.uhabits.models.*;
 
 import java.util.*;
 
+import static org.isoron.uhabits.models.HabitList.Order.*;
+
 /**
  * In-memory implementation of {@link HabitList}.
  */
@@ -33,6 +35,8 @@ public class MemoryHabitList extends HabitList
     @NonNull
     private LinkedList<Habit> list;
 
+    private Comparator<Habit> comparator = null;
+
     public MemoryHabitList()
     {
         super();
@@ -57,6 +61,7 @@ public class MemoryHabitList extends HabitList
 
         if (id == null) habit.setId((long) list.size());
         list.addLast(habit);
+        resort();
     }
 
     @Override
@@ -82,7 +87,8 @@ public class MemoryHabitList extends HabitList
     public HabitList getFiltered(HabitMatcher matcher)
     {
         MemoryHabitList habits = new MemoryHabitList(matcher);
-        for(Habit h : this) if (matcher.matches(h)) habits.add(h);
+        habits.comparator = comparator;
+        for (Habit h : this) if (matcher.matches(h)) habits.add(h);
         return habits;
     }
 
@@ -112,6 +118,13 @@ public class MemoryHabitList extends HabitList
         list.add(toPos, from);
     }
 
+    @Override
+    public void setOrder(Order order)
+    {
+        this.comparator = getComparatorByOrder(order);
+        resort();
+    }
+
     @Override
     public int size()
     {
@@ -123,4 +136,27 @@ public class MemoryHabitList extends HabitList
     {
         // NOP
     }
+
+    private Comparator<Habit> getComparatorByOrder(Order order)
+    {
+        Comparator<Habit> nameComparator =
+            (h1, h2) -> h1.getName().compareTo(h2.getName());
+
+        Comparator<Habit> colorComparator = (h1, h2) -> {
+            Integer c1 = h1.getColor();
+            Integer c2 = h2.getColor();
+            if (c1.equals(c2)) return nameComparator.compare(h1, h2);
+            else return c1.compareTo(c2);
+        };
+
+        if (order == BY_POSITION) return null;
+        if (order == BY_NAME) return nameComparator;
+        if (order == BY_COLOR) return colorComparator;
+        throw new IllegalStateException();
+    }
+
+    private void resort()
+    {
+        if (comparator != null) Collections.sort(list, comparator);
+    }
 }

app/src/main/java/org/isoron/uhabits/models/sqlite/SQLiteHabitList.java

@@ -289,4 +289,10 @@ public class SQLiteHabitList extends HabitList
         super.repair();
         rebuildOrder();
     }
+
+    @Override
+    public void setOrder(Order order)
+    {
+        throw new NotImplementedException("Not implemented");
+    }
 }

app/src/test/java/org/isoron/uhabits/models/HabitListTest.java

@@ -30,6 +30,7 @@ import static junit.framework.Assert.*;
 import static org.hamcrest.CoreMatchers.*;
 import static org.hamcrest.MatcherAssert.*;
 import static org.hamcrest.core.IsEqual.equalTo;
+import static org.isoron.uhabits.models.HabitList.Order.*;
 
 @SuppressWarnings("JavaDoc")
 public class HabitListTest extends BaseUnitTest
@@ -70,7 +71,7 @@ public class HabitListTest extends BaseUnitTest
     }
 
     @Test
-    public void testSize()
+    public void test_size()
     {
         assertThat(habitList.size(), equalTo(10));
     }
@@ -179,4 +180,52 @@ public class HabitListTest extends BaseUnitTest
 
         MatcherAssert.assertThat(writer.toString(), equalTo(expectedCSV));
     }
+
+    @Test
+    public void test_ordering()
+    {
+        HabitList list = modelFactory.buildHabitList();
+        Habit h1 = fixtures.createEmptyHabit();
+        h1.setName("A Habit");
+        h1.setColor(2);
+
+        Habit h2 = fixtures.createEmptyHabit();
+        h2.setName("B Habit");
+        h2.setColor(2);
+
+        Habit h3 = fixtures.createEmptyHabit();
+        h3.setName("C Habit");
+        h3.setColor(0);
+
+        Habit h4 = fixtures.createEmptyHabit();
+        h4.setName("D Habit");
+        h4.setColor(1);
+
+        list.add(h3);
+        list.add(h1);
+        list.add(h4);
+        list.add(h2);
+
+        list.setOrder(BY_POSITION);
+        assertThat(list.getByPosition(0), equalTo(h3));
+        assertThat(list.getByPosition(1), equalTo(h1));
+        assertThat(list.getByPosition(2), equalTo(h4));
+        assertThat(list.getByPosition(3), equalTo(h2));
+
+        list.setOrder(BY_NAME);
+        assertThat(list.getByPosition(0), equalTo(h1));
+        assertThat(list.getByPosition(1), equalTo(h2));
+        assertThat(list.getByPosition(2), equalTo(h3));
+        assertThat(list.getByPosition(3), equalTo(h4));
+
+        list.remove(h1);
+        list.add(h1);
+        assertThat(list.getByPosition(0), equalTo(h1));
+
+        list.setOrder(BY_COLOR);
+        assertThat(list.getByPosition(0), equalTo(h3));
+        assertThat(list.getByPosition(1), equalTo(h4));
+        assertThat(list.getByPosition(2), equalTo(h1));
+        assertThat(list.getByPosition(3), equalTo(h2));
+    }
 }