| /* |
| * Copyright (c) 1997, 2017, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.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; |
| import java.lang.ref.SoftReference; |
| |
| |
| /** |
| * 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> { |
| |
| // volatile since multiple threads may access queue reference |
| private volatile SoftReference<ConcurrentLinkedQueue<T>> queue; |
| |
| /** |
| * 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 = getQueue().poll(); |
| if(t==null) |
| return create(); |
| return t; |
| } |
| |
| private ConcurrentLinkedQueue<T> getQueue() { |
| SoftReference<ConcurrentLinkedQueue<T>> q = queue; |
| if (q != null) { |
| ConcurrentLinkedQueue<T> d = q.get(); |
| if (d != null) |
| return d; |
| } |
| |
| // overwrite the queue |
| ConcurrentLinkedQueue<T> d = new ConcurrentLinkedQueue<T>(); |
| queue = new SoftReference<ConcurrentLinkedQueue<T>>(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. |
| * |
| * <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; |
| } |
| |
| @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<javax.xml.bind.Unmarshaller> { |
| 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<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. |
| } |
| |
| @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; |
| } |
| |
| } |
| } |