org.eclipse.scada.da.utils.daemon.DaemonStarter.java Source code

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Here is the source code for org.eclipse.scada.da.utils.daemon.DaemonStarter.java

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/*******************************************************************************
 * Copyright (c) 2012, 2013 TH4 SYSTEMS GmbH and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     TH4 SYSTEMS GmbH - initial API and implementation
 *******************************************************************************/
package org.eclipse.scada.da.utils.daemon;

import java.util.Arrays;
import java.util.LinkedList;
import java.util.Queue;

import org.apache.commons.daemon.Daemon;
import org.apache.commons.daemon.DaemonContext;
import org.apache.commons.daemon.DaemonController;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A simple implementation of the {@link DaemonController} interface for
 * local starting of {@link Daemon} implementations.
 * 
 * @author Jens Reimann
 */
public class DaemonStarter implements DaemonController {

    private static final Logger logger = LoggerFactory.getLogger(DaemonStarter.class);

    public static void main(final String[] args) throws Exception {
        if (args.length == 0) {
            throw new RuntimeException("syntax: DaemonStarter <daemon class name>");
        }

        final Queue<String> argList = new LinkedList<String>();
        argList.addAll(Arrays.asList(args));

        new DaemonStarter(Class.forName(argList.poll()), argList.toArray(new String[0]));

        while (true) {
            Thread.sleep(1000);
        }
    }

    private final Daemon daemon;

    public DaemonStarter(final Class<?> className, final String[] args) throws Exception {
        final Object o = className.newInstance();
        if (!(o instanceof Daemon)) {
            throw new RuntimeException(String.format("Class must implement '%s'", Daemon.class));
        }

        final DaemonController controller = this;
        this.daemon = (Daemon) o;
        this.daemon.init(new DaemonContext() {

            @Override
            public String[] getArguments() {
                return args;
            }

            @Override
            public DaemonController getController() {
                return controller;
            }
        });
        this.daemon.start();

    }

    @Override
    public void fail() throws IllegalStateException {
        logger.error("Service failed");
        System.exit(-1);
    }

    @Override
    public void fail(final String arg0) throws IllegalStateException {
        logger.error("Service failed: " + arg0);
        System.exit(-1);
    }

    @Override
    public void fail(final Exception arg0) throws IllegalStateException {
        logger.error("Service failed", arg0);
    }

    @Override
    public void fail(final String arg0, final Exception arg1) throws IllegalStateException {
        logger.error(String.format("Service failed: '%s'", arg0), arg1);
    }

    @Override
    public void reload() throws IllegalStateException {
        try {
            this.daemon.stop();
            this.daemon.start();
        } catch (final Exception e) {
            fail("Failed to reload", e);
        }
    }

    @Override
    public void shutdown() throws IllegalStateException {
        if (this.daemon != null) {
            try {
                this.daemon.stop();
            } catch (final Exception e) {
                fail("Failed to shut down", e);
            }
        }
        System.exit(0);
    }
}