DefaultExecutorManager.java

/*
 * Copyright 2004-2009 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 org.compass.core.executor;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import org.compass.core.CompassException;
import org.compass.core.config.CompassConfigurable;
import org.compass.core.config.CompassEnvironment;
import org.compass.core.config.CompassSettings;
import org.compass.core.config.ConfigurationException;
import org.compass.core.executor.concurrent.ConcurrentExecutorManager;
import org.compass.core.executor.spi.InternalExecutorManager;
import org.compass.core.util.ClassUtils;

/**
 * The "default" implementation of an executor manager. Simply delegates operations
 * to an internal executor manager created based on {@link org.compass.core.config.CompassEnvironment.ExecutorManager}
 * settings.
 *
 * @author kimchy
 */
public class DefaultExecutorManager implements ExecutorManager, CompassConfigurable {

    private InternalExecutorManager executorManager;

    public void configure(CompassSettings settings) throws CompassException {

        String executorManagerType = settings.getSetting(CompassEnvironment.ExecutorManager.EXECUTOR_MANAGER_TYPE, ConcurrentExecutorManager.class.getName());

        if (executorManagerType.equals(CompassEnvironment.ExecutorManager.Concurrent.NAME)) {
            executorManagerType = ConcurrentExecutorManager.class.getName();
        } else if (executorManagerType.equals(CompassEnvironment.ExecutorManager.Scheduled.NAME)) {
            executorManagerType = ScheduledExecutorService.class.getName();
        } else if (executorManagerType.equals(CompassEnvironment.ExecutorManager.WorkManager.NAME)) {
            executorManagerType = "org.compass.core.executor.workmanager.WorkManagerExecutorManager";
        } else if (executorManagerType.equals(CompassEnvironment.ExecutorManager.CommonJ.NAME)) {
            executorManagerType = "org.compass.core.executor.commonj.WorkManagerExecutorManager";
        }

        try {
            executorManager = (InternalExecutorManager) ClassUtils.forName(executorManagerType, settings.getClassLoader()).newInstance();
        } catch (Exception e) {
            throw new ConfigurationException("Failed to create executor manager [" + executorManagerType + "]", e);
        }

        if (executorManager instanceof CompassConfigurable) {
            ((CompassConfigurable) executorManager).configure(settings);
        }
    }

    public <T> List<Future<T>> invokeAllWithLimitBailOnException(Collection<Callable<T>> tasks, int concurrencyThreshold) {
        List<Future<T>> futures = invokeAllWithLimit(tasks, concurrencyThreshold);
        for (Future<T> future : futures) {
            try {
                future.get();
            } catch (InterruptedException e) {
                throw new ExecutorException("Failed to execute, interrupted", e);
            } catch (ExecutionException e) {
                if (e.getCause() instanceof CompassException) {
                    throw (CompassException) e.getCause();
                }
                throw new ExecutorException("Failed to execute", e.getCause());
            }
        }
        return futures;
    }

    public <T> List<Future<T>> invokeAllWithLimit(Collection<Callable<T>> tasks, int concurrencyThreshold) {
        if (tasks.size() == 0) {
            return new ArrayList<Future<T>>(0);
        }
        List<Future<T>> futures;
        if (tasks.size() > concurrencyThreshold) {
            try {
                futures = invokeAll(tasks);
            } catch (InterruptedException e) {
                throw new ExecutorException("Interrupted while executing tasks", e);
            }
        } else {
            futures = new ArrayList<Future<T>>();
            for (Callable<T> commit : tasks) {
                try {
                    futures.add(new DummyFuture<T>(commit.call()));
                } catch (Exception e) {
                    futures.add(new DummyFuture<T>(e));
                }
            }
        }
        return futures;
    }

    public void close() {
        executorManager.close();
    }

    public void submit(Runnable task) {
        executorManager.submit(task);
    }

    public <T> Future<T> submit(Callable<T> task) {
        return executorManager.submit(task);
    }

    public <T> List<Future<T>> invokeAll(Collection<Callable<T>> tasks) throws InterruptedException {
        return executorManager.invokeAll(tasks);
    }

    public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
        return executorManager.schedule(callable, delay, unit);
    }

    public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
        return executorManager.scheduleAtFixedRate(command, initialDelay, period, unit);
    }

    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
        return executorManager.scheduleWithFixedDelay(command, initialDelay, delay, unit);
    }

}