de.cosmocode.palava.core.Main.java Source code

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Here is the source code for de.cosmocode.palava.core.Main.java

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/**
 * Copyright 2010 CosmoCode GmbH
 *
 * 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 de.cosmocode.palava.core;

import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.io.Writer;
import java.util.Properties;

import org.apache.commons.io.IOUtils;
import org.kohsuke.args4j.CmdLineException;
import org.kohsuke.args4j.CmdLineParser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.io.Closeables;

import de.cosmocode.collections.MultiProperties;
import de.cosmocode.commons.State;

/**
 * Application entry point.
 *
 * @since 2.0
 * @author Willi Schoenborn
 * @author Tobias Sarnowski
 */
public final class Main {

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

    private final Options options = new Options();

    private final Framework framework;

    private Main(String[] args) {
        final CmdLineParser parser = new CmdLineParser(options);

        try {
            parser.parseArgument(args);
        } catch (CmdLineException e) {
            System.err.println("Usage:  java [options] configuration-files...");
            parser.printUsage(System.err);
            throw new IllegalArgumentException(e);
        }

        if (options.isInterceptStreams()) {
            SystemStreamWrapper.redirectSystemStreams();
            LOG.info("SYSOUT and SYSERR will be logged through the logging system");
        }

        LOG.info("Options: {}", options);
        LOG.info("Environment: {}", System.getenv());
        LOG.info("System: {}", System.getProperties());

        final Properties properties;

        try {
            properties = MultiProperties.load(options.getConfigs());
        } catch (IOException e) {
            throw new IllegalArgumentException(e);
        }

        framework = Palava.newFramework(properties);
    }

    private void start() {
        try {
            framework.start();
            persistState();
            /* CHECKSTYLE:OFF */
        } catch (RuntimeException e) {
            /* CHECKSTYLE:ON */
            LOG.error("startup failed", e);
            e.printStackTrace();
            stop();
            System.exit(1);
        }
    }

    private void stop() {
        try {
            framework.stop();
        } finally {
            persistState();
        }
    }

    private void persistState() {
        if (options.getStateFile() == null)
            return;

        try {
            final State state = framework == null ? State.FAILED : framework.currentState();
            final Writer writer = new FileWriter(options.getStateFile());
            try {
                IOUtils.write(state.name() + "\n", writer);
            } finally {
                writer.close();
            }
        } catch (IOException e) {
            throw new IllegalArgumentException("cannot persist state to file", e);
        }
    }

    private void waitIfNecessary() {
        if (options.isNoAutoShutdown()) {
            LOG.debug("Automatic shutdown disabled; running until someone else triggers the shutdown");

            synchronized (this) {
                try {
                    wait();
                } catch (InterruptedException e) {
                    // it's ok, shut down
                    LOG.debug("main thread interrupted", e);
                }
            }
        }
    }

    /**
     * Application entry point.
     *
     * @param args command line arguments
     */
    public static void main(String[] args) {
        AsciiArt.print();

        final Main main;

        try {
            main = new Main(args);
            /* CHECKSTYLE:OFF */
        } catch (RuntimeException e) {
            /* CHECKSTYLE:ON */
            LOG.error("configuration error", e);
            printToStdErr(e);
            System.exit(1);
            throw e;
        }

        main.start();

        LOG.debug("Adding shutdown hook");
        Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {

            @Override
            public void run() {
                main.stop();
                synchronized (main) {
                    main.notify();
                }
            }

        }));

        main.waitIfNecessary();
        System.exit(0);
    }

    private static void printToStdErr(Exception e) {
        final OutputStream stream = new FileOutputStream(FileDescriptor.err);
        final PrintStream stderr = new PrintStream(stream);
        e.printStackTrace(stderr);
        Closeables.closeQuietly(stderr);
    }

}