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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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
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*
* 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).
*
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*
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package sun.java2d;
import java.lang.ref.Reference;
/**
* This ReentrantContextProvider implementation uses a ThreadLocal to hold
* the first ReentrantContext per thread and a ReentrantContextProviderCLQ to
* store child ReentrantContext instances needed during recursion.
*
* Note: this implementation may keep up to one context in memory per thread.
* Child contexts for recursive uses are stored in the queue using a WEAK
* reference by default unless specified in the 2 argument constructor.
*
* @param <K> ReentrantContext subclass
*/
public abstract class ReentrantContextProviderTL<K extends ReentrantContext>
extends ReentrantContextProvider<K>
{
// Thread-local storage:
private final ThreadLocal<Reference<K>> ctxTL
= new ThreadLocal<Reference<K>>();
// ReentrantContext CLQ provider for child contexts:
private final ReentrantContextProviderCLQ<K> ctxProviderCLQ;
/**
* Create a new ReentrantContext provider using the given reference type
* among hard, soft or weak.
* It uses weak reference for the child contexts.
*
* @param refType reference type
*/
public ReentrantContextProviderTL(final int refType) {
this(refType, REF_WEAK);
}
/**
* Create a new ReentrantContext provider using the given reference types
* among hard, soft or weak
*
* @param refTypeTL reference type used by ThreadLocal
* @param refTypeCLQ reference type used by ReentrantContextProviderCLQ
*/
public ReentrantContextProviderTL(final int refTypeTL, final int refTypeCLQ)
{
super(refTypeTL);
final ReentrantContextProviderTL<K> parent = this;
this.ctxProviderCLQ = new ReentrantContextProviderCLQ<K>(refTypeCLQ) {
@Override
protected K newContext() {
return parent.newContext();
}
};
}
/**
* Give a ReentrantContext instance for the current thread
*
* @return ReentrantContext instance
*/
@Override
public final K acquire() {
K ctx = null;
final Reference<K> ref = ctxTL.get();
if (ref != null) {
ctx = ref.get();
}
if (ctx == null) {
// create a new ReentrantContext if none is available
ctx = newContext();
// update thread local reference:
ctxTL.set(getOrCreateReference(ctx));
}
// Check reentrance:
if (ctx.usage == USAGE_TL_INACTIVE) {
ctx.usage = USAGE_TL_IN_USE;
} else {
// get or create another ReentrantContext from CLQ provider:
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