com.github.sviperll.concurrent.SimpleFuture Maven / Gradle / Ivy

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/*
 * Copyright (c) 2014, Victor Nazarov 
 * 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 the Victor Nazarov 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  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 com.github.sviperll.concurrent;

import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

/**
 *
 * @author Victor Nazarov 
 */
public class SimpleFuture implements Future {
    private final Object lock = new Object();
    private V value = null;
    private boolean isCancelled = false;
    private boolean isDone = false;

    public void set(V value) {
        synchronized(lock) {
            if (isDone || isCancelled)
                throw new IllegalStateException("SimpleFuture already set");
            this.value = value;
            isDone = true;
            lock.notifyAll();
        }
    }
    
    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
        boolean wasCancelled;
        synchronized(lock) {
            wasCancelled = isCancelled;
            isCancelled = true;
            lock.notifyAll();
        }
        return wasCancelled;
    }

    @Override
    public boolean isCancelled() {
        synchronized(lock) {
            return isCancelled;
        }
    }

    @Override
    public boolean isDone() {
        synchronized(lock) {
            return isDone;
        }
    }

    @Override
    public V get() throws InterruptedException, ExecutionException {
        synchronized(lock) {
            while (!isDone && !isCancelled)
                lock.wait();
            if (isCancelled)
                throw new CancellationException();
            return value;
        }
    }

    @Override
    public V get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
        synchronized(lock) {
            while (!isDone && !isCancelled)
                lock.wait(unit.toMillis(timeout));
            if (isCancelled)
                throw new CancellationException();
            if (!isDone)
                throw new TimeoutException();
            return value;
        }
    }

}