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The Groovy and Java high-level concurrency library offering actors, dataflow, CSP, agents, parallel collections, fork/join and more

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// GPars - Groovy Parallel Systems
//
// Copyright © 2008-2012  The original author or authors
//
// Licensed 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 groovyx.gpars.dataflow.operator;

import groovyx.gpars.dataflow.Promise;

import java.util.concurrent.TimeUnit;

/**
 * Represents a non-immediate PoisonPill that counts stopped operators and can be used to wait for all the operators to terminate.
 *
 * @author Vaclav Pech
 */
public final class CountingPoisonPill extends PoisonPill {
    private final PoisonTrackCounter poisonTrackCounter;

    /**
     * Creates a non-immediate instance that could be used to stop operators in a network.
     *
     * @param count The number of operators that need to be stopped before the join() method returns.
     */
    public CountingPoisonPill(final int count) {
        poisonTrackCounter = new PoisonTrackCounter(count);
    }

    /**
     * Blocks until the number of terminated operators reaches the number specified in the constructor
     *
     * @throws InterruptedException If the current thread gets interrupted during the blocking
     */
    public void join() throws InterruptedException {
        poisonTrackCounter.join();
    }

    /**
     * Blocks until the number of terminated operators reaches the number specified in the constructor
     *
     * @param timeout the maximum time to wait
     * @param unit    the time unit of the {@code timeout} argument
     * @throws InterruptedException If the current thread gets interrupted during the blocking
     */
    public void join(final long timeout, final TimeUnit unit) throws InterruptedException {
        poisonTrackCounter.join(timeout, unit);
    }

    /**
     * Retrieves the promise for termination
     *
     * @return A Promise instance that will be bound when all the requested dataflow processors have been terminated
     */
    public Promise getTermination() {
        return poisonTrackCounter.getTermination();
    }

    @Override
    void countDown() {
        poisonTrackCounter.countDown();
    }
}