ArrayHashSet: Add 'getOrAdd(key)' identity method to conveniently get the identity or add it, if not exist yet

2 files changed, 41 insertions, 5 deletions

diff --git a/src/java/com/jogamp/common/util/ArrayHashSet.java b/src/java/com/jogamp/common/util/ArrayHashSet.java
index af1c0bd..d1e555f 100644
--- a/src/java/com/jogamp/common/util/ArrayHashSet.java
+++ b/src/java/com/jogamp/common/util/ArrayHashSet.java
@@ -358,15 +358,38 @@ public class ArrayHashSet
     //
 
     /**
-     * Identity method allowing to fetch an equivalent object, using the internal hash map.
+     * Identity method allowing to get the identical object, using the internal hash map.
      * <br>
      * This is an O(1) operation.
      * 
-     * @param ident argument to find an equivalent Object within this list
-     * @return the Object contained in this list equivalent to the given <code>ident</code> Object
+     * @param key hash source to find the identical Object within this list
+     * @return object from this list, identical to the given <code>key</code> hash code,
+     * or null if not contained
      */
-    public final Object get(Object ident) {
-        return map.get(ident);
+    public final Object get(Object key) {
+        return map.get(key);
+    }
+
+    /**
+     * Identity method allowing to get the identical object, using the internal hash map.<br>
+     * If the <code>key</code> is not yet contained, add it.
+     * <br>
+     * This is an O(1) operation.
+     *
+     * @param key hash source to find the identical Object within this list
+     * @return object from this list, identical to the given <code>key</code> hash code,
+     * or add the given <code>key</code> and return it.
+     */
+    public final Object getOrAdd(Object key) {
+        Object identity = get(key);
+        if(null == identity) {
+            // object not contained yet, add it
+            if(!this.add(key)) {
+                throw new InternalError("Key not mapped, but contained in list: "+key);
+            }
+            identity = key;
+        }
+        return identity;
     }
 
 }
diff --git a/src/junit/com/jogamp/common/util/TestArrayHashSet01.java b/src/junit/com/jogamp/common/util/TestArrayHashSet01.java
index 5486671..2946959 100644
--- a/src/junit/com/jogamp/common/util/TestArrayHashSet01.java
+++ b/src/junit/com/jogamp/common/util/TestArrayHashSet01.java
@@ -107,6 +107,19 @@ public class TestArrayHashSet01 {
 
         Assert.assertTrue(!l.add(q)); // add same
         Assert.assertTrue(!l.add(p6_22_34)); // add equivalent
+
+        q = (Dummy) l.getOrAdd(p6_22_34); // not added test
+        Assert.assertNotNull(q);
+        Assert.assertEquals(p6_22_34, q);
+        Assert.assertTrue(p6_22_34.hashCode() == q.hashCode());
+        Assert.assertTrue(p6_22_34 != q); // diff reference
+
+        Dummy p1_2_3 = new Dummy(1, 2, 3); // a new one ..
+        q = (Dummy) l.getOrAdd(p1_2_3); // added test
+        Assert.assertNotNull(q);
+        Assert.assertEquals(p1_2_3, q);
+        Assert.assertTrue(p1_2_3.hashCode() == q.hashCode());
+        Assert.assertTrue(p1_2_3 == q); // _same_ reference, since getOrAdd added it
     }
 
     public static void main(String args[]) throws IOException {