src/share/jaxws_classes/com/sun/xml/internal/ws/util/Pool.java

Tue, 06 Mar 2012 16:09:35 -0800

author
ohair
date
Tue, 06 Mar 2012 16:09:35 -0800
changeset 286
f50545b5e2f1
child 368
0989ad8c0860
permissions
-rw-r--r--

7150322: Stop using drop source bundles in jaxws
Reviewed-by: darcy, ohrstrom

ohair@286 1 /*
ohair@286 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
ohair@286 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ohair@286 4 *
ohair@286 5 * This code is free software; you can redistribute it and/or modify it
ohair@286 6 * under the terms of the GNU General Public License version 2 only, as
ohair@286 7 * published by the Free Software Foundation. Oracle designates this
ohair@286 8 * particular file as subject to the "Classpath" exception as provided
ohair@286 9 * by Oracle in the LICENSE file that accompanied this code.
ohair@286 10 *
ohair@286 11 * This code is distributed in the hope that it will be useful, but WITHOUT
ohair@286 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ohair@286 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
ohair@286 14 * version 2 for more details (a copy is included in the LICENSE file that
ohair@286 15 * accompanied this code).
ohair@286 16 *
ohair@286 17 * You should have received a copy of the GNU General Public License version
ohair@286 18 * 2 along with this work; if not, write to the Free Software Foundation,
ohair@286 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ohair@286 20 *
ohair@286 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@286 22 * or visit www.oracle.com if you need additional information or have any
ohair@286 23 * questions.
ohair@286 24 */
ohair@286 25
ohair@286 26 package com.sun.xml.internal.ws.util;
ohair@286 27
ohair@286 28 import com.sun.xml.internal.ws.api.pipe.Tube;
ohair@286 29 import com.sun.xml.internal.ws.api.pipe.TubeCloner;
ohair@286 30
ohair@286 31 import javax.xml.bind.JAXBContext;
ohair@286 32 import javax.xml.bind.JAXBException;
ohair@286 33 import java.util.concurrent.ConcurrentLinkedQueue;
ohair@286 34 import java.lang.ref.WeakReference;
ohair@286 35
ohair@286 36 /**
ohair@286 37 * General-purpose object pool.
ohair@286 38 *
ohair@286 39 * <p>
ohair@286 40 * In many parts of the runtime, we need to pool instances of objects that
ohair@286 41 * are expensive to create (such as JAXB objects, StAX parsers, {@link Tube} instances.)
ohair@286 42 *
ohair@286 43 * <p>
ohair@286 44 * This class provides a default implementation of such a pool.
ohair@286 45 *
ohair@286 46 * TODO: improve the implementation
ohair@286 47 *
ohair@286 48 * @author Kohsuke Kawaguchi
ohair@286 49 */
ohair@286 50 public abstract class Pool<T> {
ohair@286 51
ohair@286 52 // volatile since multiple threads may access queue reference
ohair@286 53 private volatile WeakReference<ConcurrentLinkedQueue<T>> queue;
ohair@286 54
ohair@286 55 /**
ohair@286 56 * Gets a new object from the pool.
ohair@286 57 *
ohair@286 58 * <p>
ohair@286 59 * If no object is available in the pool, this method creates a new one.
ohair@286 60 *
ohair@286 61 * @return
ohair@286 62 * always non-null.
ohair@286 63 */
ohair@286 64 public final T take() {
ohair@286 65 T t = getQueue().poll();
ohair@286 66 if(t==null)
ohair@286 67 return create();
ohair@286 68 return t;
ohair@286 69 }
ohair@286 70
ohair@286 71 private ConcurrentLinkedQueue<T> getQueue() {
ohair@286 72 WeakReference<ConcurrentLinkedQueue<T>> q = queue;
ohair@286 73 if (q != null) {
ohair@286 74 ConcurrentLinkedQueue<T> d = q.get();
ohair@286 75 if (d != null)
ohair@286 76 return d;
ohair@286 77 }
ohair@286 78
ohair@286 79 // overwrite the queue
ohair@286 80 ConcurrentLinkedQueue<T> d = new ConcurrentLinkedQueue<T>();
ohair@286 81 queue = new WeakReference<ConcurrentLinkedQueue<T>>(d);
ohair@286 82
ohair@286 83 return d;
ohair@286 84 }
ohair@286 85
ohair@286 86 /**
ohair@286 87 * Returns an object back to the pool.
ohair@286 88 */
ohair@286 89 public final void recycle(T t) {
ohair@286 90 getQueue().offer(t);
ohair@286 91 }
ohair@286 92
ohair@286 93 /**
ohair@286 94 * Creates a new instance of object.
ohair@286 95 *
ohair@286 96 * <p>
ohair@286 97 * This method is used when someone wants to
ohair@286 98 * {@link #take() take} an object from an empty pool.
ohair@286 99 *
ohair@286 100 * <p>
ohair@286 101 * Also note that multiple threads may call this method
ohair@286 102 * concurrently.
ohair@286 103 */
ohair@286 104 protected abstract T create();
ohair@286 105
ohair@286 106
ohair@286 107 /**
ohair@286 108 * JAXB {@link javax.xml.bind.Marshaller} pool.
ohair@286 109 */
ohair@286 110 public static final class Marshaller extends Pool<javax.xml.bind.Marshaller> {
ohair@286 111 private final JAXBContext context;
ohair@286 112
ohair@286 113 public Marshaller(JAXBContext context) {
ohair@286 114 this.context = context;
ohair@286 115 }
ohair@286 116
ohair@286 117 protected javax.xml.bind.Marshaller create() {
ohair@286 118 try {
ohair@286 119 return context.createMarshaller();
ohair@286 120 } catch (JAXBException e) {
ohair@286 121 // impossible
ohair@286 122 throw new AssertionError(e);
ohair@286 123 }
ohair@286 124 }
ohair@286 125 }
ohair@286 126
ohair@286 127 /**
ohair@286 128 * JAXB {@link javax.xml.bind.Marshaller} pool.
ohair@286 129 */
ohair@286 130 public static final class Unmarshaller extends Pool<javax.xml.bind.Unmarshaller> {
ohair@286 131 private final JAXBContext context;
ohair@286 132
ohair@286 133 public Unmarshaller(JAXBContext context) {
ohair@286 134 this.context = context;
ohair@286 135 }
ohair@286 136
ohair@286 137 protected javax.xml.bind.Unmarshaller create() {
ohair@286 138 try {
ohair@286 139 return context.createUnmarshaller();
ohair@286 140 } catch (JAXBException e) {
ohair@286 141 // impossible
ohair@286 142 throw new AssertionError(e);
ohair@286 143 }
ohair@286 144 }
ohair@286 145 }
ohair@286 146
ohair@286 147 /**
ohair@286 148 * {@link Tube} pool.
ohair@286 149 */
ohair@286 150 public static final class TubePool extends Pool<Tube> {
ohair@286 151 private final Tube master;
ohair@286 152
ohair@286 153 public TubePool(Tube master) {
ohair@286 154 this.master = master;
ohair@286 155 recycle(master); // we'll use master as a part of the pool, too.
ohair@286 156 }
ohair@286 157
ohair@286 158 protected Tube create() {
ohair@286 159 return TubeCloner.clone(master);
ohair@286 160 }
ohair@286 161 }
ohair@286 162 }

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