1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000 1.2 +++ b/src/share/jaxws_classes/com/sun/istack/internal/Pool.java Tue Mar 06 16:09:35 2012 -0800 1.3 @@ -0,0 +1,116 @@ 1.4 +/* 1.5 + * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. 1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 1.7 + * 1.8 + * This code is free software; you can redistribute it and/or modify it 1.9 + * under the terms of the GNU General Public License version 2 only, as 1.10 + * published by the Free Software Foundation. Oracle designates this 1.11 + * particular file as subject to the "Classpath" exception as provided 1.12 + * by Oracle in the LICENSE file that accompanied this code. 1.13 + * 1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT 1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 1.17 + * version 2 for more details (a copy is included in the LICENSE file that 1.18 + * accompanied this code). 1.19 + * 1.20 + * You should have received a copy of the GNU General Public License version 1.21 + * 2 along with this work; if not, write to the Free Software Foundation, 1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 1.23 + * 1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 1.25 + * or visit www.oracle.com if you need additional information or have any 1.26 + * questions. 1.27 + */ 1.28 + 1.29 +package com.sun.istack.internal; 1.30 + 1.31 +import java.util.concurrent.ConcurrentLinkedQueue; 1.32 +import java.lang.ref.WeakReference; 1.33 + 1.34 +/** 1.35 + * Pool of reusable objects that are indistinguishable from each other, 1.36 + * such as JAXB marshallers. 1.37 + * 1.38 + * @author Kohsuke Kawaguchi 1.39 + */ 1.40 +public interface Pool<T> { 1.41 + 1.42 + /** 1.43 + * Gets a new object from the pool. 1.44 + * 1.45 + * <p> 1.46 + * If no object is available in the pool, this method creates a new one. 1.47 + */ 1.48 + @NotNull T take(); 1.49 + 1.50 + /** 1.51 + * Returns an object back to the pool. 1.52 + */ 1.53 + void recycle(@NotNull T t); 1.54 + 1.55 + /** 1.56 + * Default implementation that uses {@link ConcurrentLinkedQueue} 1.57 + * as the data store. 1.58 + * 1.59 + * <h2>Note for Implementors</h2> 1.60 + * <p> 1.61 + * Don't rely on the fact that this class extends from {@link ConcurrentLinkedQueue}. 1.62 + */ 1.63 + public abstract class Impl<T> implements Pool<T> { 1.64 + 1.65 + private volatile WeakReference<ConcurrentLinkedQueue<T>> queue; 1.66 + 1.67 + /** 1.68 + * Gets a new object from the pool. 1.69 + * 1.70 + * <p> 1.71 + * If no object is available in the pool, this method creates a new one. 1.72 + * 1.73 + * @return 1.74 + * always non-null. 1.75 + */ 1.76 + public final @NotNull T take() { 1.77 + T t = getQueue().poll(); 1.78 + if(t==null) { 1.79 + return create(); 1.80 + } 1.81 + return t; 1.82 + } 1.83 + 1.84 + /** 1.85 + * Returns an object back to the pool. 1.86 + */ 1.87 + public final void recycle(T t) { 1.88 + getQueue().offer(t); 1.89 + } 1.90 + 1.91 + private ConcurrentLinkedQueue<T> getQueue() { 1.92 + WeakReference<ConcurrentLinkedQueue<T>> q = queue; 1.93 + if (q != null) { 1.94 + ConcurrentLinkedQueue<T> d = q.get(); 1.95 + if (d != null) { 1.96 + return d; 1.97 + } 1.98 + } 1.99 + // overwrite the queue 1.100 + ConcurrentLinkedQueue<T> d = new ConcurrentLinkedQueue<T>(); 1.101 + queue = new WeakReference<ConcurrentLinkedQueue<T>>(d); 1.102 + 1.103 + return d; 1.104 + } 1.105 + 1.106 + /** 1.107 + * Creates a new instance of object. 1.108 + * 1.109 + * <p> 1.110 + * This method is used when someone wants to 1.111 + * {@link #take() take} an object from an empty pool. 1.112 + * 1.113 + * <p> 1.114 + * Also note that multiple threads may call this method 1.115 + * concurrently. 1.116 + */ 1.117 + protected abstract @NotNull T create(); 1.118 + } 1.119 +}