edu.iu.harp.schstatic.TaskMonitor.java Source code

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Here is the source code for edu.iu.harp.schstatic.TaskMonitor.java

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/*
 * Copyright 2013-2016 Indiana University
 * 
 * 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 edu.iu.harp.schstatic;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.Semaphore;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import edu.iu.harp.schdynamic.ComputeUtil;
import edu.iu.harp.schdynamic.Input;
import edu.iu.harp.schdynamic.Output;

public class TaskMonitor<I, O, T extends Task<I, O>> implements Runnable {
    protected static final Log LOG = LogFactory.getLog(TaskMonitor.class);

    private final T taskObject;
    private final BlockingQueue<Input<I>> inputQueue;
    private final BlockingQueue<Output<O>> outputQueue;
    private int inputCount;
    private int outputCount;
    private int errorCount;
    private boolean isRunning;
    private final Semaphore barrier1;
    private final Semaphore barrier2;

    TaskMonitor(int taskID, T task, Submitter<I> submitter, int numTasks, Semaphore barrier1) {
        this.taskObject = task;
        this.taskObject.setTaskID(taskID);
        this.taskObject.setNumTasks(numTasks);
        this.taskObject.setSubmitter(submitter);
        this.inputQueue = new LinkedBlockingQueue<>();
        this.outputQueue = new LinkedBlockingQueue<>();
        this.inputCount = 0;
        this.outputCount = 0;
        this.errorCount = 0;
        this.barrier1 = barrier1;
        this.barrier2 = new Semaphore(0);
    }

    T getTask() {
        return taskObject;
    }

    private synchronized void start() {
        if (!isRunning) {
            isRunning = true;
            inputCount += inputQueue.size();
        }
    }

    synchronized void submit(Input<I> input) {
        inputQueue.add(input);
        if (isRunning) {
            inputCount++;
        }
    }

    private synchronized void pauseOrStop() {
        if (isRunning) {
            isRunning = false;
            inputCount -= inputQueue.size();
        }
    }

    synchronized void cleanInputQueue() {
        if (!isRunning) {
            inputQueue.clear();
        }
    }

    synchronized boolean hasOutput() {
        return inputCount > outputCount;
    }

    O waitForOutput() {
        // If no output is available, wait for one
        if (hasOutput()) {
            boolean isFailed = false;
            Output<O> output = null;
            do {
                try {
                    output = outputQueue.take();
                    isFailed = false;
                } catch (Exception e) {
                    output = null;
                    isFailed = true;
                    LOG.error("Error when waiting output", e);
                }
            } while (isFailed);
            outputCount++;
            if (output.isError()) {
                errorCount++;
            }
            return output.getOutput();
        } else {
            return null;
        }
    }

    boolean hasError() {
        int count = errorCount;
        errorCount = 0;
        return count > 0;
    }

    void release() {
        barrier2.release();
    }

    @Override
    public void run() {
        start();
        while (true) {
            try {
                Input<I> input = inputQueue.take();
                if (input != null) {
                    if (input.isStop()) {
                        pauseOrStop();
                        break;
                    } else if (input.isPause()) {
                        // Pause
                        pauseOrStop();
                        barrier1.release();
                        ComputeUtil.acquire(barrier2);
                        start();
                    } else {
                        O output = null;
                        boolean isFailed = false;
                        try {
                            output = taskObject.run(input.getInput());
                        } catch (Exception e) {
                            output = null;
                            isFailed = true;
                            LOG.error("Error when processing input", e);
                        }
                        if (isFailed || output == null) {
                            outputQueue.add(new Output<>(null, true));
                        } else {
                            outputQueue.add(new Output<>(output, false));
                        }
                    }
                }
            } catch (Throwable t) {
                LOG.error("Fail to run input", t);
            }
        }
    }
}