--- jsr166/src/jsr166e/LongAdderTable.java	2011/07/31 14:20:01	1.1
+++ jsr166/src/jsr166e/LongAdderTable.java	2012/08/13 15:52:33	1.9
@@ -4,41 +4,44 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
-package jsr166e.extra;
+package jsr166e;
 import jsr166e.LongAdder;
-import java.util.concurrent.ConcurrentHashMap;
 import java.util.Map;
 import java.util.Set;
 import java.io.Serializable;
 
 /**
  * A keyed table of adders, that may be useful in computing frequency
- * counts and histograms, or may be used a form of multiset.  A {@link
- * LongAdder} is associated with each key. Keys are added to the table
- * implicitly upon any attempt to update, or may be added explicitly
- * using method {@link #install}.
+ * counts and histograms, or may be used as a form of multiset.  A
+ * {@link LongAdder} is associated with each key. Keys are added to
+ * the table implicitly upon any attempt to update, or may be added
+ * explicitly using method {@link #install}.
  *
  * <p><em>jsr166e note: This class is targeted to be placed in
  * java.util.concurrent.atomic<em>
  *
+ * @since 1.8
  * @author Doug Lea
  */
 public class LongAdderTable<K> implements Serializable {
     /** Relies on default serialization */
     private static final long serialVersionUID = 7249369246863182397L;
 
-    /** Concurrency parameter for map -- we assume high contention */
-    private static final int MAP_SEGMENTS =
-        Math.max(16, Runtime.getRuntime().availableProcessors());
-
     /** The underlying map */
-    private final ConcurrentHashMap<K, LongAdder> map;
+    private final ConcurrentHashMapV8<K, LongAdder> map;
+
+    static final class CreateAdder
+        implements ConcurrentHashMapV8.Fun<Object, LongAdder> {
+        public LongAdder apply(Object unused) { return new LongAdder(); }
+    }
+
+    private static final CreateAdder createAdder = new CreateAdder();
 
     /**
      * Creates a new empty table.
      */
     public LongAdderTable() {
-        map = new ConcurrentHashMap<K, LongAdder>(16, 0.75f, MAP_SEGMENTS);
+        map = new ConcurrentHashMapV8<K, LongAdder>();
     }
 
     /**
@@ -50,13 +53,7 @@ public class LongAdderTable<K> implement
      * @return the adder associated with the key
      */
     public LongAdder install(K key) {
-        LongAdder a = map.get(key);
-        if (a == null) {
-            LongAdder r = new LongAdder();
-            if ((a = map.putIfAbsent(key, r)) == null)
-                a = r;
-        }
-        return a;
+        return map.computeIfAbsent(key, createAdder);
     }
 
     /**
@@ -68,13 +65,7 @@ public class LongAdderTable<K> implement
      * @param x the value to add
      */
     public void add(K key, long x) {
-        LongAdder a = map.get(key);
-        if (a == null) {
-            LongAdder r = new LongAdder();
-            if ((a = map.putIfAbsent(key, r)) == null)
-                a = r;
-        }
-        a.add(x);
+        map.computeIfAbsent(key, createAdder).add(x);
     }
 
     /**
@@ -136,7 +127,7 @@ public class LongAdderTable<K> implement
     /**
      * Returns the sum totalled across all keys.
      *
-     * @return the sum totalled across all keys.
+     * @return the sum totalled across all keys
      */
     public long sumAll() {
         long sum = 0L;
@@ -156,7 +147,7 @@ public class LongAdderTable<K> implement
     /**
      * Totals, then resets, the sums associated with all keys.
      *
-     * @return the sum totalled across all keys.
+     * @return the sum totalled across all keys
      */
     public long sumThenResetAll() {
         long sum = 0L;