Abgabe Übungstest 5

src/Aufgabe5Test.java

@@ -78,4 +78,19 @@ public class Aufgabe5Test {
         assertEquals(hashCode2, map.hashCode());
         assertNotEquals(hashCode1, hashCode2);
     }
+
+    @Test
+    public void testDelKey() {
+        MassiveForceHashMap map = new MassiveForceHashMap();
+        NamedBody sun1 = new NamedBody(SolSystem4.SUN_NAMED);
+        NamedBody earth1 = new NamedBody(SolSystem4.EARTH_NAMED);
+        NamedBody moon1 = new NamedBody(SolSystem4.MOON_NAMED);
+        map.put(sun1, new Vector3());
+        map.put(earth1, new Vector3());
+        map.put(moon1, new Vector3());
+        assertNotNull(map.get(sun1));
+        assertNotNull(map.delete(sun1));
+        assertNull(map.get(sun1));
+        assertNull(map.delete(sun1));
+    }
 }

src/MassiveForceHashMap.java

@@ -65,16 +65,36 @@ public class MassiveForceHashMap {
      * Precondition: key != null.
      */
     public Vector3 get(Massive key) {
+        int pos = find(key);
+        return (pos == -1) ? null : values[pos];
+    }
+
+    private int find(Massive key) {
         int idx = ((key.hashCode() % keys.length) + keys.length) % keys.length;
         for (int i = 0; i < keys.length; i++) {
             int pos = (idx + i) % keys.length;
             if (keys[pos] == null) {
                 break;
             } else if (keys[pos].equals(key)) {
-                return values[pos];
+                return pos;
             }
         }
-        return null;
+        return -1;
+    }
+
+    /**
+     * Deletes the mapping for the specified key from this map if present.
+     * Returns the previous value associated with key, or null if there was
+     * no mapping for key.
+     * Precondition: key != null
+     */
+    public Vector3 delete(Massive key) {
+        int pos = find(key);
+        if (pos == -1) return null;
+
+        Vector3 val = values[pos];
+        values[pos] = null;
+        return val;
     }
 
     /**