| /* |
| * Copyright 2015, Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are |
| * met: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following disclaimer |
| * in the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| package io.grpc.internal; |
| |
| import com.google.common.base.Preconditions; |
| |
| import java.util.ArrayDeque; |
| import java.util.concurrent.Executor; |
| import java.util.logging.Level; |
| import java.util.logging.Logger; |
| |
| /** |
| * Executes a task directly in the calling thread, unless it's a reentrant call in which case the |
| * task is enqueued and executed once the calling task completes. |
| * |
| * <p>The {@code Executor} assumes that reentrant calls are rare and its fast path is thus |
| * optimized for that - avoiding queuing and additional object creation altogether. |
| * |
| * <p>This class is not thread-safe. |
| */ |
| class SerializeReentrantCallsDirectExecutor implements Executor { |
| |
| private static final Logger log = |
| Logger.getLogger(SerializeReentrantCallsDirectExecutor.class.getName()); |
| |
| private boolean executing; |
| // Lazily initialized if a reentrant call is detected. |
| private ArrayDeque<Runnable> taskQueue; |
| |
| @Override |
| public void execute(Runnable task) { |
| Preconditions.checkNotNull(task, "'task' must not be null."); |
| if (!executing) { |
| executing = true; |
| try { |
| task.run(); |
| } catch (Throwable t) { |
| log.log(Level.SEVERE, "Exception while executing runnable " + task, t); |
| } finally { |
| if (taskQueue != null) { |
| completeQueuedTasks(); |
| } |
| executing = false; |
| } |
| } else { |
| enqueue(task); |
| } |
| } |
| |
| private void completeQueuedTasks() { |
| Runnable task = null; |
| while ((task = taskQueue.poll()) != null) { |
| try { |
| task.run(); |
| } catch (Throwable t) { |
| // Log it and keep going |
| log.log(Level.SEVERE, "Exception while executing runnable " + task, t); |
| } |
| } |
| } |
| |
| private void enqueue(Runnable r) { |
| if (taskQueue == null) { |
| taskQueue = new ArrayDeque<Runnable>(4); |
| } |
| taskQueue.add(r); |
| } |
| } |