001: /*
002: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
003: *
004: * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
005: *
006: * The contents of this file are subject to the terms of either the GNU
007: * General Public License Version 2 only ("GPL") or the Common Development
008: * and Distribution License("CDDL") (collectively, the "License"). You
009: * may not use this file except in compliance with the License. You can obtain
010: * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html
011: * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific
012: * language governing permissions and limitations under the License.
013: *
014: * When distributing the software, include this License Header Notice in each
015: * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt.
016: * Sun designates this particular file as subject to the "Classpath" exception
017: * as provided by Sun in the GPL Version 2 section of the License file that
018: * accompanied this code. If applicable, add the following below the License
019: * Header, with the fields enclosed by brackets [] replaced by your own
020: * identifying information: "Portions Copyrighted [year]
021: * [name of copyright owner]"
022: *
023: * Contributor(s):
024: *
025: * If you wish your version of this file to be governed by only the CDDL or
026: * only the GPL Version 2, indicate your decision by adding "[Contributor]
027: * elects to include this software in this distribution under the [CDDL or GPL
028: * Version 2] license." If you don't indicate a single choice of license, a
029: * recipient has the option to distribute your version of this file under
030: * either the CDDL, the GPL Version 2 or to extend the choice of license to
031: * its licensees as provided above. However, if you add GPL Version 2 code
032: * and therefore, elected the GPL Version 2 license, then the option applies
033: * only if the new code is made subject to such option by the copyright
034: * holder.
035: */
036:
037: package com.sun.xml.ws.util;
038:
039: import com.sun.xml.ws.api.pipe.Tube;
040: import com.sun.xml.ws.api.pipe.TubeCloner;
041:
042: import javax.xml.bind.JAXBContext;
043: import javax.xml.bind.JAXBException;
044: import java.util.concurrent.ConcurrentLinkedQueue;
045:
046: /**
047: * General-purpose object pool.
048: *
049: * <p>
050: * In many parts of the runtime, we need to pool instances of objects that
051: * are expensive to create (such as JAXB objects, StAX parsers, {@link Tube} instances.)
052: *
053: * <p>
054: * This class provides a default implementation of such a pool.
055: *
056: * TODO: improve the implementation
057: *
058: * @author Kohsuke Kawaguchi
059: */
060: public abstract class Pool<T> {
061: private final ConcurrentLinkedQueue<T> queue = new ConcurrentLinkedQueue<T>();
062:
063: /**
064: * Gets a new object from the pool.
065: *
066: * <p>
067: * If no object is available in the pool, this method creates a new one.
068: *
069: * @return
070: * always non-null.
071: */
072: public final T take() {
073: T t = queue.poll();
074: if (t == null)
075: return create();
076: return t;
077: }
078:
079: /**
080: * Returns an object back to the pool.
081: */
082: public final void recycle(T t) {
083: queue.offer(t);
084: }
085:
086: /**
087: * Creates a new instance of object.
088: *
089: * <p>
090: * This method is used when someone wants to
091: * {@link #take() take} an object from an empty pool.
092: *
093: * <p>
094: * Also note that multiple threads may call this method
095: * concurrently.
096: */
097: protected abstract T create();
098:
099: /**
100: * JAXB {@link javax.xml.bind.Marshaller} pool.
101: */
102: public static final class Marshaller extends
103: Pool<javax.xml.bind.Marshaller> {
104: private final JAXBContext context;
105:
106: public Marshaller(JAXBContext context) {
107: this .context = context;
108: }
109:
110: protected javax.xml.bind.Marshaller create() {
111: try {
112: return context.createMarshaller();
113: } catch (JAXBException e) {
114: // impossible
115: throw new AssertionError(e);
116: }
117: }
118: }
119:
120: /**
121: * JAXB {@link javax.xml.bind.Marshaller} pool.
122: */
123: public static final class Unmarshaller extends
124: Pool<javax.xml.bind.Unmarshaller> {
125: private final JAXBContext context;
126:
127: public Unmarshaller(JAXBContext context) {
128: this .context = context;
129: }
130:
131: protected javax.xml.bind.Unmarshaller create() {
132: try {
133: return context.createUnmarshaller();
134: } catch (JAXBException e) {
135: // impossible
136: throw new AssertionError(e);
137: }
138: }
139: }
140:
141: /**
142: * {@link Tube} pool.
143: */
144: public static final class TubePool extends Pool<Tube> {
145: private final Tube master;
146:
147: public TubePool(Tube master) {
148: this .master = master;
149: recycle(master); // we'll use master as a part of the pool, too.
150: }
151:
152: protected Tube create() {
153: return TubeCloner.clone(master);
154: }
155: }
156: }
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