org.openengsb.openengsbplugin.tools.OpenEngSBJavaRunner Maven / Gradle / Ivy

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/**
 * Licensed to the Austrian Association for Software Tool Integration (AASTI)
 * under one or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership. The AASTI licenses this file to you 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.openengsb.openengsbplugin.tools;

import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;

import org.ops4j.io.Pipe;
import org.ops4j.pax.runner.platform.PlatformException;
import org.ops4j.pax.runner.platform.internal.CommandLineBuilder;

public class OpenEngSBJavaRunner {

    private Process process;
    private Thread shutdownHook;
    private Pipe errorStreamMapper;
    private Pipe outStreamMapper;
    private Pipe inStreamMapper;
    private Runnable shutdownRunnable;
    private String[] commandLine;
    private Map environment;

    public OpenEngSBJavaRunner(CommandLineBuilder command, Map env) {
        commandLine = command.toArray();
        environment = env;
    }

    public synchronized void exec() throws PlatformException {
        startProcess();
        createShutdownHook();
        Runtime.getRuntime().addShutdownHook(shutdownHook);
        waitForExit();
    }

    private void startProcess() throws PlatformException {
        try {
            ProcessBuilder processBuilder = new ProcessBuilder();
            processBuilder.command(commandLine);
            Map env = processBuilder.environment();
            for (Entry entry : environment.entrySet()) {
                env.put(entry.getKey(), entry.getValue());
            }
            process = processBuilder.start();
        } catch (IOException e) {
            throw new PlatformException("Could not start up the process", e);
        }
    }

    public void shutdown() {
        try {
            synchronized (shutdownHook) {
                if (shutdownHook != null) {
                    Runtime.getRuntime().removeShutdownHook(shutdownHook);
                    process = null;
                    shutdownHook.run();
                    shutdownHook = null;
                }
            }
        } catch (IllegalStateException ignore) {
        }
    }

    public void waitForExit() {
        synchronized (process) {
            try {
                process.waitFor();
                shutdown();
            } catch (Throwable e) {
                shutdown();
            }
        }
    }

    private void createShutdownHook() {
        createPipes();
        createShutdownRunnable();
        shutdownHook = new Thread(shutdownRunnable, "OpenEngSB Runner Shutdown Hook");
    }

    private void createPipes() {
        errorStreamMapper = new Pipe(process.getErrorStream(), System.err).start("Error pipe");
        outStreamMapper = new Pipe(process.getInputStream(), System.out).start("Out pipe");
        inStreamMapper = new Pipe(process.getOutputStream(), System.in).start("In pipe");
    }

    private void createShutdownRunnable() {
        shutdownRunnable = new Runnable() {
            @Override
            public void run() {
                stopPipes();
                destroyProcess();
            }
        };
    }

    private void stopPipes() {
        inStreamMapper.stop();
        outStreamMapper.stop();
        errorStreamMapper.stop();
    }

    private void destroyProcess() {
        try {
            process.destroy();
        } catch (Exception ignore) {
        }
    }

}