co.cask.cdap.internal.app.runtime.distributed.AbstractTwillProgramController.java Source code

Introduction

Here is the source code for co.cask.cdap.internal.app.runtime.distributed.AbstractTwillProgramController.java

Source

/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.internal.app.runtime.distributed;

import co.cask.cdap.app.runtime.ProgramController;
import co.cask.cdap.internal.app.runtime.AbstractProgramController;
import com.google.common.util.concurrent.Futures;
import org.apache.twill.api.RunId;
import org.apache.twill.api.TwillController;
import org.apache.twill.common.Threads;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A {@link ProgramController} that control program through twill.
 */
abstract class AbstractTwillProgramController extends AbstractProgramController implements ProgramController {

    private static final Logger LOG = LoggerFactory.getLogger(AbstractTwillProgramController.class);

    protected final String programName;
    protected final TwillController twillController;
    private volatile boolean stopRequested;

    protected AbstractTwillProgramController(String programName, TwillController twillController, RunId runId) {
        super(programName, runId);
        this.programName = programName;
        this.twillController = twillController;
    }

    /**
     * Get the RunId associated with the Twill controller.
     * @return the Twill RunId
     */
    public RunId getTwillRunId() {
        return twillController.getRunId();
    }

    /**
     * Starts listening to TwillController state changes. For internal use only.
     * The listener cannot be binded in constructor to avoid reference leak.
     *
     * @return this instance.
     */
    public ProgramController startListen() {
        twillController.onRunning(new Runnable() {
            @Override
            public void run() {
                LOG.info("Twill program running: {} {}", programName, twillController.getRunId());
                started();
            }
        }, Threads.SAME_THREAD_EXECUTOR);

        twillController.onTerminated(new Runnable() {
            @Override
            public void run() {
                LOG.info("Twill program terminated: {} {}", programName, twillController.getRunId());
                if (stopRequested) {
                    // Service was killed
                    stop();
                } else {
                    // Service completed by itself. Simply signal the state change of this controller.
                    complete();
                }
            }
        }, Threads.SAME_THREAD_EXECUTOR);
        return this;
    }

    @Override
    protected final void doSuspend() throws Exception {
        twillController.sendCommand(ProgramCommands.SUSPEND).get();
    }

    @Override
    protected final void doResume() throws Exception {
        twillController.sendCommand(ProgramCommands.RESUME).get();
    }

    @Override
    protected final void doStop() throws Exception {
        stopRequested = true;
        Futures.getUnchecked(twillController.terminate());
    }
}