pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.4.0 / lucene / src / java / org / apache / lucene / util / CloseableThreadLocal.java

diff --git a/lucene-java-3.4.0/lucene/src/java/org/apache/lucene/util/CloseableThreadLocal.java b/lucene-java-3.4.0/lucene/src/java/org/apache/lucene/util/CloseableThreadLocal.java
deleted file mode 100644 (file)
index 97d873f..0000000
--- a/lucene-java-3.4.0/lucene/src/java/org/apache/lucene/util/CloseableThreadLocal.java
+++ /dev/null
@@ -1,107 +0,0 @@
-package org.apache.lucene.util;
-
-/**
- * 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.
- */
-
-import java.io.Closeable;
-import java.lang.ref.WeakReference;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.Map;
-
-/** Java's builtin ThreadLocal has a serious flaw:
- *  it can take an arbitrarily long amount of time to
- *  dereference the things you had stored in it, even once the
- *  ThreadLocal instance itself is no longer referenced.
- *  This is because there is single, master map stored for
- *  each thread, which all ThreadLocals share, and that
- *  master map only periodically purges "stale" entries.
- *
- *  While not technically a memory leak, because eventually
- *  the memory will be reclaimed, it can take a long time
- *  and you can easily hit OutOfMemoryError because from the
- *  GC's standpoint the stale entries are not reclaimable.
- * 
- *  This class works around that, by only enrolling
- *  WeakReference values into the ThreadLocal, and
- *  separately holding a hard reference to each stored
- *  value.  When you call {@link #close}, these hard
- *  references are cleared and then GC is freely able to
- *  reclaim space by objects stored in it.
- *
- *  We can not rely on {@link ThreadLocal#remove()} as it
- *  only removes the value for the caller thread, whereas
- *  {@link #close} takes care of all
- *  threads.  You should not call {@link #close} until all
- *  threads are done using the instance.
- *
- * @lucene.internal
- */
-
-public class CloseableThreadLocal<T> implements Closeable {
-
-  private ThreadLocal<WeakReference<T>> t = new ThreadLocal<WeakReference<T>>();
-
-  private Map<Thread,T> hardRefs = new HashMap<Thread,T>();
-  
-  protected T initialValue() {
-    return null;
-  }
-  
-  public T get() {
-    WeakReference<T> weakRef = t.get();
-    if (weakRef == null) {
-      T iv = initialValue();
-      if (iv != null) {
-        set(iv);
-        return iv;
-      } else
-        return null;
-    } else {
-      return weakRef.get();
-    }
-  }
-
-  public void set(T object) {
-
-    t.set(new WeakReference<T>(object));
-
-    synchronized(hardRefs) {
-      hardRefs.put(Thread.currentThread(), object);
-
-      // Purge dead threads
-      for (Iterator<Thread> it = hardRefs.keySet().iterator(); it.hasNext();) {
-        final Thread t = it.next();
-        if (!t.isAlive())
-          it.remove();
-      }
-    }
-  }
-
-  public void close() {
-    // Clear the hard refs; then, the only remaining refs to
-    // all values we were storing are weak (unless somewhere
-    // else is still using them) and so GC may reclaim them:
-    hardRefs = null;
-    // Take care of the current thread right now; others will be
-    // taken care of via the WeakReferences.
-    if (t != null) {
-      t.remove();
-    }
-    t = null;
-  }
-}