io.vertigo.dynamo.impl.search.WritableFuture.java Source code

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Here is the source code for io.vertigo.dynamo.impl.search.WritableFuture.java

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/**
 * vertigo - simple java starter
 *
 * Copyright (C) 2013-2017, KleeGroup, direction.technique@kleegroup.com (http://www.kleegroup.com)
 * KleeGroup, Centre d'affaire la Boursidiere - BP 159 - 92357 Le Plessis Robinson Cedex - France
 *
 * 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 io.vertigo.dynamo.impl.search;

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

import io.vertigo.lang.Assertion;

/**
 * WritableFuture for set result after execution.
 * @see "org.apache.http.concurrent.BasicFuture"
 * @author npiedeloup
 * @param <V> Result type
 */
public final class WritableFuture<V> implements Future<V> {

    private volatile boolean completed;
    private volatile boolean cancelled;
    private volatile V futureResult;
    private volatile Exception futureException;

    /** {@inheritDoc} */
    @Override
    public boolean isCancelled() {
        return this.cancelled;
    }

    /** {@inheritDoc} */
    @Override
    public boolean isDone() {
        return this.completed;
    }

    /** {@inheritDoc} */
    @Override
    public synchronized V get() throws InterruptedException, ExecutionException {
        while (!this.completed) {
            wait();
        }
        return getResult();
    }

    /** {@inheritDoc} */
    @Override
    public synchronized V get(final long timeout, final TimeUnit unit)
            throws InterruptedException, ExecutionException, TimeoutException {
        Assertion.checkNotNull(unit, "Time unit was null");
        //-----
        final long msecs = unit.toMillis(timeout);
        final long startTime = msecs <= 0 ? 0 : System.currentTimeMillis();
        long waitTime = msecs;
        if (this.completed) {
            return getResult();
        } else if (waitTime <= 0) {
            throw new TimeoutException();
        } else {
            for (;;) {
                wait(waitTime);
                if (this.completed) {
                    return getResult();
                }
                waitTime = msecs - (System.currentTimeMillis() - startTime);
                if (waitTime <= 0) {
                    throw new TimeoutException();
                }
            }
        }
    }

    /** {@inheritDoc} */
    @Override
    public synchronized boolean cancel(final boolean mayInterruptIfRunning) {
        if (this.completed) {
            return false; //@see Future api
        }
        this.completed = true;
        this.cancelled = true;
        notifyAll();
        return true;
    }

    /**
     * Mark this execution as success.
     * @param result Result of execution
     */
    public synchronized void success(final V result) {
        Assertion.checkState(!this.completed, "Task already completed");
        //-----
        this.completed = true;
        this.futureResult = result;
        notifyAll();
    }

    /**
     * Mark this execution as failed.
     * @param exception Failure reason
     */
    public synchronized void fail(final Exception exception) {
        Assertion.checkState(!this.completed, "Task already completed");
        //-----
        this.completed = true;
        this.futureException = exception;
        notifyAll();
    }

    private V getResult() throws ExecutionException {
        if (futureException != null) {
            throw new ExecutionException(futureException);
        }
        return futureResult;
    }

}