pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / util / Counter.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/Counter.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/Counter.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/util/Counter.java
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+package org.apache.lucene.util;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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.
+ */
+
+/**
+ * Simple counter class
+ * 
+ * @lucene.internal
+ * @lucene.experimental
+ */
+public abstract class Counter {
+
+  /**
+   * Adds the given delta to the counters current value
+   * 
+   * @param delta
+   *          the delta to add
+   * @return the counters updated value
+   */
+  public abstract long addAndGet(long delta);
+
+  /**
+   * Returns the counters current value
+   * 
+   * @return the counters current value
+   */
+  public abstract long get();
+
+  /**
+   * Returns a new counter. The returned counter is not thread-safe.
+   */
+  public static Counter newCounter() {
+    return newCounter(false);
+  }
+
+  /**
+   * Returns a new counter.
+   * 
+   * @param threadSafe
+   *          <code>true</code> if the returned counter can be used by multiple
+   *          threads concurrently.
+   * @return a new counter.
+   */
+  public static Counter newCounter(boolean threadSafe) {
+    return threadSafe ? new AtomicCounter() : new SerialCounter();
+  }
+
+  private final static class SerialCounter extends Counter {
+    private long count = 0;
+
+    @Override
+    public long addAndGet(long delta) {
+      return count += delta;
+    }
+
+    @Override
+    public long get() {
+      return count;
+    };
+  }
+
+  private final static class AtomicCounter extends Counter {
+    private final AtomicLong count = new AtomicLong();
+
+    @Override
+    public long addAndGet(long delta) {
+      return count.addAndGet(delta);
+    }
+
+    @Override
+    public long get() {
+      return count.get();
+    }
+
+  }
+}