com.sun.xml.ws.util.Pool Maven / Gradle / Ivy
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2017 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://oss.oracle.com/licenses/CDDL+GPL-1.1
* or LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.xml.ws.util;
import com.sun.xml.ws.api.pipe.Tube;
import com.sun.xml.ws.api.pipe.TubeCloner;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.lang.ref.SoftReference;
/**
* General-purpose object pool.
*
*
* 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.)
*
*
* This class provides a default implementation of such a pool.
*
* TODO: improve the implementation
*
* @author Kohsuke Kawaguchi
*/
public abstract class Pool {
// volatile since multiple threads may access queue reference
private volatile SoftReference> queue;
/**
* Gets a new object from the pool.
*
*
* If no object is available in the pool, this method creates a new one.
*
* @return
* always non-null.
*/
public final T take() {
T t = getQueue().poll();
if(t==null)
return create();
return t;
}
private ConcurrentLinkedQueue getQueue() {
SoftReference> q = queue;
if (q != null) {
ConcurrentLinkedQueue d = q.get();
if (d != null)
return d;
}
// overwrite the queue
ConcurrentLinkedQueue d = new ConcurrentLinkedQueue();
queue = new SoftReference>(d);
return d;
}
/**
* Returns an object back to the pool.
*/
public final void recycle(T t) {
getQueue().offer(t);
}
/**
* Creates a new instance of object.
*
*
* This method is used when someone wants to
* {@link #take() take} an object from an empty pool.
*
*
* 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 {
private final JAXBContext context;
public Marshaller(JAXBContext context) {
this.context = context;
}
@Override
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 {
private final JAXBContext context;
public Unmarshaller(JAXBContext context) {
this.context = context;
}
@Override
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 {
private final Tube master;
public TubePool(Tube master) {
this.master = master;
recycle(master); // we'll use master as a part of the pool, too.
}
@Override
protected Tube create() {
return TubeCloner.clone(master);
}
/**
*
* @return master tubeline from pool
* @deprecated Expected to be used in rare cases where access to master
* tubeline is required and safe, such as Stub.close()."
*/
@Deprecated()
public final Tube takeMaster() {
return master;
}
}
}