/*
* Copyright 2005-2006 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package com.sun.xml.internal.ws.util;
import com.sun.xml.internal.ws.api.pipe.Tube;
import com.sun.xml.internal.ws.api.pipe.TubeCloner;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import java.util.concurrent.ConcurrentLinkedQueue;
/**
* General-purpose object pool.
*
* <p>
* In many parts of the runtime, we need to pool instances of objects that
* are expensive to create (such as JAXB objects, StAX parsers, {@link Tube} instances.)
*
* <p>
* This class provides a default implementation of such a pool.
*
* TODO: improve the implementation
*
* @author Kohsuke Kawaguchi
*/
public abstract class Pool<T> {
private final ConcurrentLinkedQueue<T> queue = new ConcurrentLinkedQueue<T>();
/**
* Gets a new object from the pool.
*
* <p>
* If no object is available in the pool, this method creates a new one.
*
* @return
* always non-null.
*/
public final T take() {
T t = queue.poll();
if(t==null)
return create();
return t;
}
/**
* Returns an object back to the pool.
*/
public final void recycle(T t) {
queue.offer(t);
}
/**
* Creates a new instance of object.
*
* <p>
* This method is used when someone wants to
* {@link #take() take} an object from an empty pool.
*
* <p>
* Also note that multiple threads may call this method
* concurrently.
*/
protected abstract T create();
/**
* JAXB {@link javax.xml.bind.Marshaller} pool.
*/
public static final class Marshaller extends Pool<javax.xml.bind.Marshaller> {
private final JAXBContext context;
public Marshaller(JAXBContext context) {
this.context = context;
}
protected javax.xml.bind.Marshaller create() {
try {
return context.createMarshaller();
} catch (JAXBException e) {
// impossible
throw new AssertionError(e);
}
}
}
/**
* JAXB {@link javax.xml.bind.Marshaller} pool.
*/
public static final class Unmarshaller extends Pool<javax.xml.bind.Unmarshaller> {
private final JAXBContext context;
public Unmarshaller(JAXBContext context) {
this.context = context;
}
protected javax.xml.bind.Unmarshaller create() {
try {
return context.createUnmarshaller();
} catch (JAXBException e) {
// impossible
throw new AssertionError(e);
}
}
}
/**
* {@link Tube} pool.
*/
public static final class TubePool extends Pool<Tube> {
private final Tube master;
public TubePool(Tube master) {
this.master = master;
recycle(master); // we'll use master as a part of the pool, too.
}
protected Tube create() {
return TubeCloner.clone(master);
}
}
}