Main.java example

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jnode-master
/*
 * $Id$
 *
 * Copyright (C) 2003-2015 JNode.org
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; If not, write to the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
package org.jnode.boot;

import java.lang.reflect.Method;
import java.util.List;

import org.jnode.annotation.LoadStatics;
import org.jnode.annotation.SharedStatics;
import org.jnode.annotation.Uninterruptible;
import org.jnode.bootlog.BootLogInstance;
import org.jnode.plugin.PluginDescriptor;
import org.jnode.plugin.PluginManager;
import org.jnode.plugin.PluginRegistry;
import org.jnode.plugin.manager.DefaultPluginManager;
import org.jnode.vm.Unsafe;
import org.jnode.vm.VmSystem;

/**
 * First class that is executed when JNode boots.
 *
 * @author Ewout Prangsma (epr@users.sourceforge.net)
 */
@SharedStatics
public final class Main {

    public static final String MAIN_METHOD_NAME = "vmMain";
    public static final String MAIN_METHOD_SIGNATURE = "()I";
    public static final String REGISTRY_FIELD_NAME = "pluginRegistry";

    /**
     *  Initialized in org.jnode.build.x86.BootImageBuilder.initMain().
     */
    private static PluginRegistry pluginRegistry;

    /**
     * First java entry point after the assembler kernel has booted.
     *
     * @return int
     */
    @LoadStatics
    @Uninterruptible
    public static int vmMain() {
        //return 15;
        try {
            Unsafe.debug("Starting JNode\n");
            final long start = VmSystem.currentKernelMillis();

            Unsafe.debug("VmSystem.initialize\n");
            VmSystem.initialize();
            
            // Load the plugins from the initjar
            BootLogInstance.get().info("Loading initjar plugins");
            final InitJarProcessor proc = new InitJarProcessor(VmSystem.getInitJar());
            List<PluginDescriptor> descriptors = proc.loadPlugins(pluginRegistry);

            BootLogInstance.get().info("Starting PluginManager");
            final PluginManager piMgr = new DefaultPluginManager(pluginRegistry);
            piMgr.startSystemPlugins(descriptors);

            final ClassLoader loader = pluginRegistry.getPluginsClassLoader();
            final String mainClassName = proc.getMainClassName();
            final Class<?> mainClass;
            if (mainClassName != null) {
                mainClass = loader.loadClass(mainClassName);
            } else {
                BootLogInstance.get().warn("No Main-Class found");
                mainClass = null;
            }
            final long end = VmSystem.currentKernelMillis();
            System.out.println("JNode initialization finished in " + (end - start) + "ms.");

            if (mainClass != null) {
                try {
                    final Method mainMethod = 
                        mainClass.getMethod("main", new Class[]{String[].class});
                    mainMethod.invoke(null, new Object[]{proc.getMainClassArguments()});
                } catch (NoSuchMethodException x) {
                    final Object insatnce = mainClass.newInstance();
                    if (insatnce instanceof Runnable) {
                        ((Runnable) insatnce).run();
                    } else {
                        BootLogInstance.get().warn("No valid Main-Class found");
                    }
                }
            }
        } catch (Throwable ex) {
            BootLogInstance.get().error("Error in bootstrap", ex);
            Unsafe.debugStackTrace(ex);
            sleepForever();
            return -2;
        }
        Unsafe.debug("System has finished");
        return VmSystem.getExitCode();
    }

    private static void sleepForever() {
        while (true) {
            try {
                Thread.sleep(Long.MAX_VALUE);
            } catch (InterruptedException ex) {
                // Ignore
            }
        }
    }
}