Shuts down the specified executors. - Java java.util.concurrent

Java examples for java.util.concurrent:Executors

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Description

Shuts down the specified executors.

Demo Code

/*//  w  w w  .  j a  v a 2  s. c  om
 * Copyright 2009 Red Hat, Inc.
 *
 * Red Hat 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.
 */
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

public class Main{
    /**
     * Shuts down the specified executors.
     */
    public static void terminate(Executor... executors) {
        // Check nulls.
        if (executors == null) {
            throw new NullPointerException("executors");
        }

        Executor[] executorsCopy = new Executor[executors.length];
        for (int i = 0; i < executors.length; i++) {
            if (executors[i] == null) {
                throw new NullPointerException("executors[" + i + "]");
            }
            executorsCopy[i] = executors[i];
        }

        // Check dead lock.
        final Executor currentParent = DeadLockProofWorker.PARENT.get();
        if (currentParent != null) {
            for (Executor e : executorsCopy) {
                if (e == currentParent) {
                    throw new IllegalStateException(
                            "An Executor cannot be shut down from the thread "
                                    + "acquired from itself.  Please make sure you are "
                                    + "not calling releaseExternalResources() from an "
                                    + "I/O worker thread.");
                }
            }
        }

        // Shut down all executors.
        boolean interrupted = false;
        for (Executor e : executorsCopy) {
            if (!(e instanceof ExecutorService)) {
                continue;
            }

            ExecutorService es = (ExecutorService) e;
            for (;;) {
                try {
                    es.shutdownNow();
                } catch (SecurityException ex) {
                    // Running in a restricted environment - fall back.
                    try {
                        es.shutdown();
                    } catch (SecurityException ex2) {
                        // Running in a more restricted environment.
                        // Can't shut down this executor - skip to the next.
                        break;
                    } catch (NullPointerException ex2) {
                        // Some JDK throws NPE here, but shouldn't.
                    }
                } catch (NullPointerException ex) {
                    // Some JDK throws NPE here, but shouldn't.
                }

                try {
                    if (es.awaitTermination(100, TimeUnit.MILLISECONDS)) {
                        break;
                    }
                } catch (InterruptedException ex) {
                    interrupted = true;
                }
            }
        }

        if (interrupted) {
            Thread.currentThread().interrupt();
        }
    }
}

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