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package com.sun.util.reentrant;

import java.lang.ref.Reference;
import java.util.concurrent.ConcurrentLinkedQueue;

This ReentrantContextProvider implementation uses one ConcurrentLinkedQueue to store all ReentrantContext instances (thread and its child contexts) Note: this implementation keeps less contexts in memory depending on the concurrent active threads in contrary to a ThreadLocal provider. However, it is slower in highly concurrent workloads.
Type parameters:
  • <K> – ReentrantContext subclass
/** * This ReentrantContextProvider implementation uses one ConcurrentLinkedQueue * to store all ReentrantContext instances (thread and its child contexts) * * Note: this implementation keeps less contexts in memory depending on the * concurrent active threads in contrary to a ThreadLocal provider. However, * it is slower in highly concurrent workloads. * * @param <K> ReentrantContext subclass */
public abstract class ReentrantContextProviderCLQ<K extends ReentrantContext> extends ReentrantContextProvider<K> { // ReentrantContext queue to store all contexts private final ConcurrentLinkedQueue<Reference<K>> ctxQueue = new ConcurrentLinkedQueue<Reference<K>>();
Create a new ReentrantContext provider using the given reference type among hard, soft or weak based using a ConcurrentLinkedQueue storage
Params:
  • refType – reference type
/** * Create a new ReentrantContext provider using the given reference type * among hard, soft or weak based using a ConcurrentLinkedQueue storage * * @param refType reference type */
public ReentrantContextProviderCLQ(final int refType) { super(refType); }
Give a ReentrantContext instance for the current thread
Returns:ReentrantContext instance
/** * Give a ReentrantContext instance for the current thread * * @return ReentrantContext instance */
@Override public final K acquire() { K ctx = null; // Drain queue if all referent are null: Reference<K> ref = null; while ((ctx == null) && ((ref = ctxQueue.poll()) != null)) { ctx = ref.get(); } if (ctx == null) { // create a new ReentrantContext if none is available ctx = newContext(); ctx.usage = USAGE_CLQ; } return ctx; }
Restore the given ReentrantContext instance for reuse
Params:
  • ctx – ReentrantContext instance
/** * Restore the given ReentrantContext instance for reuse * * @param ctx ReentrantContext instance */
@Override public final void release(final K ctx) { if (ctx.usage == USAGE_CLQ) { ctxQueue.offer(getOrCreateReference(ctx)); } } }