AtomicMaxUpdater refactoring

bootstrap-core/src/test/java/com/navercorp/pinpoint/bootstrap/interceptor/AtomicMaxUpdater.java

@@ -1,28 +1,31 @@
 package com.navercorp.pinpoint.bootstrap.interceptor;
 
-import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
 
 /**
  * @author emeroad
  */
 public class AtomicMaxUpdater {
 
-    private final AtomicInteger maxIndex = new AtomicInteger(-1);
+    private static final AtomicIntegerFieldUpdater<AtomicMaxUpdater> UPDATER = AtomicIntegerFieldUpdater.newUpdater(AtomicMaxUpdater.class, "maxIndex");
 
-    public boolean updateMax(int max) {
+    private volatile int maxIndex = 0;
+
+    public boolean update(int max) {
         while (true) {
-            final int currentMax = maxIndex.get();
+            final int currentMax = getIndex();
             if (currentMax >= max) {
                 return false;
             }
-            final boolean update = maxIndex.compareAndSet(currentMax, max);
+            final boolean update = UPDATER.compareAndSet(this, currentMax, max);
             if (update) {
                 return true;
             }
         }
     }
 
+
     public int getIndex() {
-        return maxIndex.get();
+        return UPDATER.get(this);
     }
 }

bootstrap-core/src/test/java/com/navercorp/pinpoint/bootstrap/interceptor/AtomicMaxUpdaterTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2014 NAVER Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.navercorp.pinpoint.bootstrap.interceptor;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+/**
+ * @author emeroad
+ */
+public class AtomicMaxUpdaterTest {
+    @Test
+    public void update() {
+        AtomicMaxUpdater updater = new AtomicMaxUpdater();
+
+        Assert.assertFalse(updater.update(0));
+
+
+        Assert.assertTrue(updater.update(1));
+
+        Assert.assertTrue(updater.update(10));
+
+        Assert.assertFalse(updater.update(5));
+        Assert.assertEquals(updater.getIndex(), 10);
+
+
+    }
+}