Java example source code file (ServerMain.java)

This example Java source code file (ServerMain.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

application_error, class, corba, exception, fileoutputstream, main_class_not_found, method, no_main_method, object, printstream, reflection, registration_failed, servercallback, servermain, string, util

The ServerMain.java Java example source code

/*
 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.corba.se.impl.activation;

import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.io.*;
import java.util.Date;
import java.util.Properties ;

import org.omg.CORBA.ORB ;
import com.sun.corba.se.spi.activation.Activator ;
import com.sun.corba.se.spi.activation.ActivatorHelper ;
import com.sun.corba.se.impl.orbutil.ORBConstants ;

/**
 * @author      Ken Cavanaugh
 * @since       JDK1.2
 */
public class ServerMain
{
    /* TODO:
    * 1.  Rewrite all uses of ORB properties to use constants from someplace.
    *     The strings are scattered between here, the ORB classes, and
    *     ServerTableEntry.
    * 2.  Consider a more general log facility.
    * 3.  Remove ServerCallback from POAORB.
    * 4.  Needs to be merged with Harold's changes to support SSL.
    * 5.  Logs need to be internationalized.
    */

    public final static int OK = 0;
    public final static int MAIN_CLASS_NOT_FOUND = 1;
    public final static int NO_MAIN_METHOD = 2;
    public final static int APPLICATION_ERROR = 3;
    public final static int UNKNOWN_ERROR = 4;
    public final static int NO_SERVER_ID = 5 ;
    public final static int REGISTRATION_FAILED = 6;

    public static String printResult( int result )
    {
        switch (result) {
            case OK :                   return "Server terminated normally" ;
            case MAIN_CLASS_NOT_FOUND : return "main class not found" ;
            case NO_MAIN_METHOD :       return "no main method" ;
            case APPLICATION_ERROR :    return "application error" ;
            case NO_SERVER_ID :         return "server ID not defined" ;
            case REGISTRATION_FAILED:   return "server registration failed" ;
            default :                   return "unknown error" ;
        }
    }

    private void redirectIOStreams()
    {
        // redirect out and err streams
        try {
            String logDirName =
                System.getProperty( ORBConstants.DB_DIR_PROPERTY ) +
                System.getProperty("file.separator") +
                ORBConstants.SERVER_LOG_DIR +
                System.getProperty("file.separator");

            File logDir = new File(logDirName);
            String server = System.getProperty(
                ORBConstants.SERVER_ID_PROPERTY ) ;

            FileOutputStream foutStream =
                new FileOutputStream(logDirName + server+".out", true);
            FileOutputStream ferrStream =
                new FileOutputStream(logDirName + server+".err", true);

            PrintStream pSout = new PrintStream(foutStream, true);
            PrintStream pSerr = new PrintStream(ferrStream, true);

            System.setOut(pSout);
            System.setErr(pSerr);

            logInformation( "Server started" ) ;

        } catch (Exception ex) {}
    }

    /** Write a time-stamped message to the indicated PrintStream.
    */
    private static void writeLogMessage( PrintStream pstream, String msg )
    {
        Date date = new Date();
        pstream.print( "[" + date.toString() + "] " + msg + "\n");
    }

    /** Write information to standard out only.
    */
    public static void logInformation( String msg )
    {
        writeLogMessage( System.out, "        " + msg ) ;
    }

    /** Write error message to standard out and standard err.
    */
    public static void logError( String msg )
    {
        writeLogMessage( System.out, "ERROR:  " + msg ) ;
        writeLogMessage( System.err, "ERROR:  " + msg ) ;
    }

    /** Write final message to log(s) and then terminate by calling
    * System.exit( code ).  If code == OK, write a normal termination
    * message to standard out, otherwise write an abnormal termination
    * message to standard out and standard error.
    */
    public static void logTerminal( String msg, int code )
    {
        if (code == 0) {
            writeLogMessage( System.out, "        " + msg ) ;
        } else {
            writeLogMessage( System.out, "FATAL:  " +
                printResult( code ) + ": " + msg ) ;

            writeLogMessage( System.err, "FATAL:  " +
                printResult( code ) + ": " + msg ) ;
        }

        System.exit( code ) ;
    }

    private Method getMainMethod( Class serverClass )
    {
        Class argTypes[] = new Class[] { String[].class } ;
        Method method = null ;

        try {
            method = serverClass.getDeclaredMethod( "main", argTypes ) ;
        } catch (Exception exc) {
            logTerminal( exc.getMessage(), NO_MAIN_METHOD ) ;
        }

        if (!isPublicStaticVoid( method ))
            logTerminal( "", NO_MAIN_METHOD ) ;

        return method ;
    }

    private boolean isPublicStaticVoid( Method method )
    {
        // check modifiers: public static
        int modifiers =  method.getModifiers ();
        if (!Modifier.isPublic (modifiers) || !Modifier.isStatic (modifiers)) {
            logError( method.getName() + " is not public static" ) ;
            return false ;
        }

        // check return type and exceptions
        if (method.getExceptionTypes ().length != 0) {
            logError( method.getName() + " declares exceptions" ) ;
            return false ;
        }

        if (!method.getReturnType().equals (Void.TYPE)) {
            logError( method.getName() + " does not have a void return type" ) ;
            return false ;
        }

        return true ;
    }

    private Method getNamedMethod( Class serverClass, String methodName )
    {
        Class argTypes[] = new Class[] { org.omg.CORBA.ORB.class } ;
        Method method = null ;

        try {
            method = serverClass.getDeclaredMethod( methodName, argTypes ) ;
        } catch (Exception exc) {
            return null ;
        }

        if (!isPublicStaticVoid( method ))
            return null ;

        return method ;
    }

    private void run(String[] args)
    {
        try {
            redirectIOStreams() ;

            String serverClassName = System.getProperty(
                ORBConstants.SERVER_NAME_PROPERTY ) ;

            // determine the class loader to be used for loading the class
            // since ServerMain is going to be in JDK and we need to have this
            // class to load application classes, this is required here.
            ClassLoader cl = Thread.currentThread().getContextClassLoader();

            if (cl == null)
                cl = ClassLoader.getSystemClassLoader();

            // determine the main class
            Class serverClass = null;

            try {
                // determine the main class, try loading with current class loader
                serverClass = Class.forName( serverClassName ) ;
            } catch (ClassNotFoundException ex) {
                // eat the exception and try to load using SystemClassLoader
                serverClass = Class.forName( serverClassName, true, cl);
            }

            if (debug)
                System.out.println("class " + serverClassName + " found");

            // get the main method
            Method mainMethod = getMainMethod( serverClass ) ;

            // This piece of code is required, to verify the server definition
            // without launching it.

            // verify the server

            boolean serverVerifyFlag = Boolean.getBoolean(
                ORBConstants.SERVER_DEF_VERIFY_PROPERTY) ;
            if (serverVerifyFlag) {
                if (mainMethod == null)
                    logTerminal("", NO_MAIN_METHOD);
                else {
                    if (debug)
                        System.out.println("Valid Server");
                    logTerminal("", OK);
                }
            }


            registerCallback( serverClass ) ;

            // build args to the main and call it
            Object params [] = new Object [1];
            params[0] = args;
            mainMethod.invoke(null, params);

        } catch (ClassNotFoundException e) {
            logTerminal("ClassNotFound exception: " + e.getMessage(),
                MAIN_CLASS_NOT_FOUND);
        } catch (Exception e) {
            logTerminal("Exception: " + e.getMessage(),
                APPLICATION_ERROR);
        }
    }

    public static void main(String[] args) {
        ServerMain server = new ServerMain();
        server.run(args);
    }

    private static final boolean debug = false;

    private int getServerId()
    {
        Integer serverId = Integer.getInteger( ORBConstants.SERVER_ID_PROPERTY ) ;

        if (serverId == null)
            logTerminal( "", NO_SERVER_ID ) ;

        return serverId.intValue() ;
    }

    private void registerCallback( Class serverClass )
    {
        Method installMethod = getNamedMethod( serverClass, "install" ) ;
        Method uninstallMethod = getNamedMethod( serverClass, "uninstall" ) ;
        Method shutdownMethod = getNamedMethod( serverClass, "shutdown" ) ;

        Properties props = new Properties() ;
        props.put( "org.omg.CORBA.ORBClass",
            "com.sun.corba.se.impl.orb.ORBImpl" ) ;
        // NOTE: Very important to pass this property, otherwise the
        // Persistent Server registration will be unsucessfull.
        props.put( ORBConstants.ACTIVATED_PROPERTY, "false" );
        String args[] = null ;
        ORB orb = ORB.init( args, props ) ;

        ServerCallback serverObj = new ServerCallback( orb,
            installMethod, uninstallMethod, shutdownMethod ) ;

        int serverId = getServerId() ;

        try {
            Activator activator = ActivatorHelper.narrow(
                orb.resolve_initial_references( ORBConstants.SERVER_ACTIVATOR_NAME ));
            activator.active(serverId, serverObj);
        } catch (Exception ex) {
            logTerminal( "exception " + ex.getMessage(),
                REGISTRATION_FAILED ) ;
        }
    }
}

class ServerCallback extends
    com.sun.corba.se.spi.activation._ServerImplBase
{
    private ORB orb;
    private transient Method installMethod ;
    private transient Method uninstallMethod ;
    private transient Method shutdownMethod ;
    private Object methodArgs[] ;

    ServerCallback(ORB orb, Method installMethod, Method uninstallMethod,
        Method shutdownMethod )
    {
        this.orb = orb;
        this.installMethod = installMethod ;
        this.uninstallMethod = uninstallMethod ;
        this.shutdownMethod = shutdownMethod ;

        orb.connect( this ) ;

        methodArgs = new Object[] { orb } ;
    }

    private void invokeMethod( Method method )
    {
        if (method != null)
            try {
                method.invoke( null, methodArgs ) ;
            } catch (Exception exc) {
                ServerMain.logError( "could not invoke " + method.getName() +
                    " method: " + exc.getMessage() ) ;
            }
    }

    // shutdown the ORB and wait for completion
    public void shutdown()
    {
        ServerMain.logInformation( "Shutdown starting" ) ;

        invokeMethod( shutdownMethod ) ;

        orb.shutdown(true);

        ServerMain.logTerminal( "Shutdown completed", ServerMain.OK ) ;
    }

    public void install()
    {
        ServerMain.logInformation( "Install starting" ) ;

        invokeMethod( installMethod ) ;

        ServerMain.logInformation( "Install completed" ) ;
    }

    public void uninstall()
    {
        ServerMain.logInformation( "uninstall starting" ) ;

        invokeMethod( uninstallMethod ) ;

        ServerMain.logInformation( "uninstall completed" ) ;
    }
}