Optimize UnifiedMap.getFirst() to not delegate to an iterator.

eclipse · Feb 15, 2016 · 09b97ee · 09b97ee
1 parent 4b63ee4
commit 09b97ee
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Showing 3 changed files with 53 additions and 5 deletions.
diff --git a/eclipse-collections/src/main/java/org/eclipse/collections/impl/map/mutable/UnifiedMap.java b/eclipse-collections/src/main/java/org/eclipse/collections/impl/map/mutable/UnifiedMap.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015 Goldman Sachs.
+ * Copyright (c) 2016 Goldman Sachs.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * and Eclipse Distribution License v. 1.0 which accompany this distribution.
@@ -995,6 +995,25 @@ else if (cur != null)
         }
     }
 
+    @Override
+    public V getFirst()
+    {
+        for (int i = 0; i < this.table.length; i += 2)
+        {
+            Object cur = this.table[i];
+            if (cur == CHAINED_KEY)
+            {
+                Object[] chain = (Object[]) this.table[i + 1];
+                return (V) chain[1];
+            }
+            if (cur != null)
+            {
+                return (V) this.table[i + 1];
+            }
+        }
+        return null;
+    }
+
     public <E> MutableMap<K, V> collectKeysAndValues(
             Iterable<E> iterable,
             Function<? super E, ? extends K> keyFunction,

diff --git a/...java/org/eclipse/collections/impl/map/strategy/mutable/UnifiedMapWithHashingStrategy.java b/...java/org/eclipse/collections/impl/map/strategy/mutable/UnifiedMapWithHashingStrategy.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015 Goldman Sachs.
+ * Copyright (c) 2016 Goldman Sachs.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * and Eclipse Distribution License v. 1.0 which accompany this distribution.
@@ -1037,6 +1037,25 @@ else if (cur != null)
         }
     }
 
+    @Override
+    public V getFirst()
+    {
+        for (int i = 0; i < this.table.length; i += 2)
+        {
+            Object cur = this.table[i];
+            if (cur == CHAINED_KEY)
+            {
+                Object[] chain = (Object[]) this.table[i + 1];
+                return (V) chain[1];
+            }
+            if (cur != null)
+            {
+                return (V) this.table[i + 1];
+            }
+        }
+        return null;
+    }
+
     public <E> MutableMap<K, V> collectKeysAndValues(
             Iterable<E> iterable,
             Function<? super E, ? extends K> keyFunction,

diff --git a/unit-tests/src/test/java/org/eclipse/collections/impl/map/mutable/UnifiedMapTestCase.java b/unit-tests/src/test/java/org/eclipse/collections/impl/map/mutable/UnifiedMapTestCase.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015 Goldman Sachs.
+ * Copyright (c) 2016 Goldman Sachs.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * and Eclipse Distribution License v. 1.0 which accompany this distribution.
@@ -57,8 +57,8 @@ public abstract class UnifiedMapTestCase extends MutableMapTestCase
     protected static final MutableList<Integer> MORE_COLLISIONS = FastList.newList(COLLISIONS)
             .with(COLLISION_6, COLLISION_7, COLLISION_8, COLLISION_9);
     protected static final String[] FREQUENT_COLLISIONS = {"\u9103\ufffe", "\u9104\uffdf",
-        "\u9105\uffc0", "\u9106\uffa1", "\u9107\uff82", "\u9108\uff63", "\u9109\uff44",
-        "\u910a\uff25", "\u910b\uff06", "\u910c\ufee7"};
+            "\u9105\uffc0", "\u9106\uffa1", "\u9107\uff82", "\u9108\uff63", "\u9109\uff44",
+            "\u910a\uff25", "\u910b\uff06", "\u910c\ufee7"};
 
     @Test
     public void valuesCollection_toArray()
@@ -852,6 +852,16 @@ public void frequentCollision()
         Assert.assertArrayEquals(expected, map.keysView().toArray());
     }
 
+    @Override
+    public void getFirst()
+    {
+        super.getFirst();
+
+        MutableMap<String, String> map = this.newMap();
+        map.collectKeysAndValues(Arrays.asList(FREQUENT_COLLISIONS), Functions.identity(), Functions.identity());
+        Assert.assertEquals(FREQUENT_COLLISIONS[0], map.getFirst());
+    }
+
     private static final class NoInstanceOfInEquals
     {
         private final int value;