| /* |
| * Copyright (c) 2016, 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 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: |
| ctx = ctxProviderCLQ.acquire(); |
| } |
| return ctx; |
| } |
| |
| /** |
| * Restore the given ReentrantContext instance for reuse |
| * |
| * @param ctx ReentrantContext instance |
| */ |
| @Override |
| public final void release(final K ctx) { |
| if (ctx.usage == USAGE_TL_IN_USE) { |
| ctx.usage = USAGE_TL_INACTIVE; |
| } else { |
| ctxProviderCLQ.release(ctx); |
| } |
| } |
| } |