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src/share/jaxws_classes/com/sun/istack/internal/Pool.java@9c07ef4934dd (annotated)

src/share/jaxws_classes/com/sun/istack/internal/Pool.java

Thu, 31 Aug 2017 15:18:52 +0800

author

aoqi

date

Thu, 31 Aug 2017 15:18:52 +0800

changeset 637

9c07ef4934dd

parent 368

0989ad8c0860

parent 0

373ffda63c9a

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation. Oracle designates this
aoqi@0	8	* particular file as subject to the "Classpath" exception as provided
aoqi@0	9	* by Oracle in the LICENSE file that accompanied this code.
aoqi@0	10	*
aoqi@0	11	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	14	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	15	* accompanied this code).
aoqi@0	16	*
aoqi@0	17	* You should have received a copy of the GNU General Public License version
aoqi@0	18	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	19	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	20	*
aoqi@0	21	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	22	* or visit www.oracle.com if you need additional information or have any
aoqi@0	23	* questions.
aoqi@0	24	*/
aoqi@0	25
aoqi@0	26	package com.sun.istack.internal;
aoqi@0	27
aoqi@0	28	import java.util.concurrent.ConcurrentLinkedQueue;
aoqi@0	29	import java.lang.ref.WeakReference;
aoqi@0	30
aoqi@0	31	/**
aoqi@0	32	* Pool of reusable objects that are indistinguishable from each other,
aoqi@0	33	* such as JAXB marshallers.
aoqi@0	34	*
aoqi@0	35	* @author Kohsuke Kawaguchi
aoqi@0	36	*/
aoqi@0	37	public interface Pool<T> {
aoqi@0	38
aoqi@0	39	/**
aoqi@0	40	* Gets a new object from the pool.
aoqi@0	41	*
aoqi@0	42	* <p>
aoqi@0	43	* If no object is available in the pool, this method creates a new one.
aoqi@0	44	*/
aoqi@0	45	@NotNull T take();
aoqi@0	46
aoqi@0	47	/**
aoqi@0	48	* Returns an object back to the pool.
aoqi@0	49	*/
aoqi@0	50	void recycle(@NotNull T t);
aoqi@0	51
aoqi@0	52	/**
aoqi@0	53	* Default implementation that uses {@link ConcurrentLinkedQueue}
aoqi@0	54	* as the data store.
aoqi@0	55	*
aoqi@0	56	* <h2>Note for Implementors</h2>
aoqi@0	57	* <p>
aoqi@0	58	* Don't rely on the fact that this class extends from {@link ConcurrentLinkedQueue}.
aoqi@0	59	*/
aoqi@0	60	public abstract class Impl<T> implements Pool<T> {
aoqi@0	61
aoqi@0	62	private volatile WeakReference<ConcurrentLinkedQueue<T>> queue;
aoqi@0	63
aoqi@0	64	/**
aoqi@0	65	* Gets a new object from the pool.
aoqi@0	66	*
aoqi@0	67	* <p>
aoqi@0	68	* If no object is available in the pool, this method creates a new one.
aoqi@0	69	*
aoqi@0	70	* @return
aoqi@0	71	* always non-null.
aoqi@0	72	*/
aoqi@0	73	public final @NotNull T take() {
aoqi@0	74	T t = getQueue().poll();
aoqi@0	75	if(t==null) {
aoqi@0	76	return create();
aoqi@0	77	}
aoqi@0	78	return t;
aoqi@0	79	}
aoqi@0	80
aoqi@0	81	/**
aoqi@0	82	* Returns an object back to the pool.
aoqi@0	83	*/
aoqi@0	84	public final void recycle(T t) {
aoqi@0	85	getQueue().offer(t);
aoqi@0	86	}
aoqi@0	87
aoqi@0	88	private ConcurrentLinkedQueue<T> getQueue() {
aoqi@0	89	WeakReference<ConcurrentLinkedQueue<T>> q = queue;
aoqi@0	90	if (q != null) {
aoqi@0	91	ConcurrentLinkedQueue<T> d = q.get();
aoqi@0	92	if (d != null) {
aoqi@0	93	return d;
aoqi@0	94	}
aoqi@0	95	}
aoqi@0	96	// overwrite the queue
aoqi@0	97	ConcurrentLinkedQueue<T> d = new ConcurrentLinkedQueue<T>();
aoqi@0	98	queue = new WeakReference<ConcurrentLinkedQueue<T>>(d);
aoqi@0	99
aoqi@0	100	return d;
aoqi@0	101	}
aoqi@0	102
aoqi@0	103	/**
aoqi@0	104	* Creates a new instance of object.
aoqi@0	105	*
aoqi@0	106	* <p>
aoqi@0	107	* This method is used when someone wants to
aoqi@0	108	* {@link #take() take} an object from an empty pool.
aoqi@0	109	*
aoqi@0	110	* <p>
aoqi@0	111	* Also note that multiple threads may call this method
aoqi@0	112	* concurrently.
aoqi@0	113	*/
aoqi@0	114	protected abstract @NotNull T create();
aoqi@0	115	}
aoqi@0	116	}