| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.tinkerpop.gremlin.hadoop.process.computer.util; |
| |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.ExecutorService; |
| import java.util.concurrent.Executors; |
| import java.util.concurrent.ForkJoinPool; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.ThreadFactory; |
| import java.util.function.Supplier; |
| |
| import com.google.common.base.Function; |
| |
| import org.apache.tinkerpop.gremlin.process.computer.ComputerResult; |
| |
| public class ComputerSubmissionHelper { |
| |
| /** |
| * Creates a {@link Executors#newSingleThreadExecutor(ThreadFactory)} configured |
| * make threads that behave like the caller, invokes a closure on it, and shuts it down. |
| * <p> |
| * This is intended to serve as an alternative to {@link ForkJoinPool#commonPool()}, |
| * which is used by {@link CompletableFuture#supplyAsync(Supplier)} (among other methods). |
| * The the single threaded executor created by this method contains a thread |
| * with the same context classloader and thread group as the thread that called |
| * this method. Threads created in this method also have predictable behavior when |
| * {@link Thread#setContextClassLoader(ClassLoader)} is invoked; threads in the |
| * common pool throw a SecurityException if the JVM has a security manager configured. |
| * <p> |
| * The name of the thread created by this method's internal executor is the concatenation of |
| * <ul> |
| * <li>the name of the thread that calls this method</li> |
| * <li>"-TP-"</li> |
| * <li>the {@code threadNameSuffix} parameter value</li> |
| * </ul> |
| * |
| * @param closure arbitrary code that has exclusive use of the supplied executor |
| * @param threadNameSuffix a string appended to the executor's thread's name |
| * @return the return value of the {@code closure} parameter |
| */ |
| public static Future<ComputerResult> runWithBackgroundThread(Function<Executor, Future<ComputerResult>> closure, |
| String threadNameSuffix) { |
| final Thread callingThread = Thread.currentThread(); |
| final ClassLoader classLoader = callingThread.getContextClassLoader(); |
| final ThreadGroup threadGroup = callingThread.getThreadGroup(); |
| final String threadName = callingThread.getName(); |
| ExecutorService submissionExecutor = null; |
| |
| try { |
| submissionExecutor = Executors.newSingleThreadExecutor(runnable -> { |
| Thread t = new Thread(threadGroup, runnable, threadName + "-TP-" + threadNameSuffix); |
| t.setContextClassLoader(classLoader); |
| return t; |
| }); |
| |
| return closure.apply(submissionExecutor); |
| } finally { |
| if (null != submissionExecutor) |
| submissionExecutor.shutdown(); // do not call shutdownNow, which could prematurely terminate the closure |
| } |
| } |
| } |