package org.tanukisoftware.wrapper;
/*
* Copyright (c) 1999, 2009 Tanuki Software, Ltd.
* http://www.tanukisoftware.com
* All rights reserved.
*
* This software is the proprietary information of Tanuki Software.
* You shall use it only in accordance with the terms of the
* license agreement you entered into with Tanuki Software.
* http://wrapper.tanukisoftware.org/doc/english/licenseOverview.html
*
*
* Portions of the Software have been derived from source code
* developed by Silver Egg Technology under the following license:
*
* Copyright (c) 2001 Silver Egg Technology
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sub-license, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*/
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
/**
* By default the WrapperSimpleApp will only wait for 2 seconds for the main
* method of the start class to complete. This was done because the main
* methods of many applications never return. It is possible to force the
* class to wait for the startup main method to complete by defining the
* following system property when launching the JVM (defaults to FALSE):
* -Dorg.tanukisoftware.wrapper.WrapperSimpleApp.waitForStartMain=TRUE
* <p>
* Using the waitForStartMain property will cause the startup to wait
* indefinitely. This is fine if the main method will always return
* within a predefined period of time. But if there is any chance that
* it could hang, then the maxStartMainWait property may be a better
* option. It allows the 2 second wait time to be overridden. To wait
* for up to 5 minutes for the startup main method to complete, set
* the property to 300 as follows (defaults to 2 seconds):
* -Dorg.tanukisoftware.wrapper.WrapperSimpleApp.maxStartMainWait=300
* <p>
* It is possible to extend this class but make absolutely sure that any
* overridden methods call their super method or the class will fail to
* function correctly. Most users will have no need to override this
* class. Remember that if overridden, the main method will also need to
* be recreated in the child class to make sure that the correct instance
* is created.
* <p>
* NOTE - The main methods of many applications are designed not to
* return. In these cases, you must either stick with the default 2 second
* startup timeout or specify a slightly longer timeout, using the
* maxStartMainWait property, to simulate the amount of time your application
* takes to start up.
* <p>
* WARNING - If the waitForStartMain is specified for an application
* whose start method never returns, the Wrapper will appear at first to be
* functioning correctly. However the Wrapper will never enter a running
* state, this means that the Windows Service Manager and several of the
* Wrapper's error recovery mechanisms will not function correctly.
*
* @author Leif Mortenson <leif@tanukisoftware.com>
*/
public class WrapperSimpleApp
implements WrapperListener, Runnable
{
/** Info level log channel */
private static WrapperPrintStream m_outInfo;
/** Error level log channel */
private static WrapperPrintStream m_outError;
/** Debug level log channel */
private static WrapperPrintStream m_outDebug;
/**
* Application's main method
*/
private Method m_mainMethod;
/**
* Command line arguments to be passed on to the application
*/
private String[] m_appArgs;
/**
* Gets set to true when the thread used to launch the application
* actuially starts.
*/
private boolean m_mainStarted;
/**
* Gets set to true when the thread used to launch the application
* completes.
*/
private boolean m_mainComplete;
/**
* Exit code to be returned if the application fails to start.
*/
private Integer m_mainExitCode;
/**
* Flag used to signify that the start method has completed.
*/
private boolean m_startComplete;
/*---------------------------------------------------------------
* Constructors
*-------------------------------------------------------------*/
/**
* Creates an instance of a WrapperSimpleApp.
*
* @param args The full list of arguments passed to the JVM.
*/
protected WrapperSimpleApp( String args[] )
{
// Initialize the WrapperManager class on startup by referencing it.
Class wmClass = WrapperManager.class;
// Set up some log channels
m_outInfo = new WrapperPrintStream( System.out, "WrapperSimpleApp: " );
m_outError = new WrapperPrintStream( System.out, "WrapperSimpleApp: " );
m_outDebug = new WrapperPrintStream( System.out, "WrapperSimpleApp Debug: " );
// Get the class name of the application
if ( args.length < 1 )
{
showUsage();
WrapperManager.stop( 1 );
return; // Will not get here
}
// Look for the specified class by name
Class mainClass;
try
{
mainClass = Class.forName( args[0] );
}
catch ( ClassNotFoundException e )
{
m_outError.println( "Unable to locate the class " + args[0] + ": " + e );
showUsage();
WrapperManager.stop( 1 );
return; // Will not get here
}
catch ( ExceptionInInitializerError e )
{
m_outError.println( "Class " + args[0] + " found but could not be initialized due to:" );
e.printStackTrace( m_outError );
WrapperManager.stop( 1 );
return; // Will not get here
}
catch ( LinkageError e )
{
m_outError.println( "Class " + args[0] + " found but could not be initialized: " + e );
WrapperManager.stop( 1 );
return; // Will not get here
}
// Look for the main method
try
{
// getDeclaredMethod will return any method named main in the specified class,
// while getMethod will only return public methods, but it will search up the
// inheritance path.
m_mainMethod = mainClass.getMethod( "main", new Class[] { String[].class } );
}
catch ( NoSuchMethodException e )
{
m_outError.println(
"Unable to locate a public static main method in class " + args[0] + ": " + e );
showUsage();
WrapperManager.stop( 1 );
return; // Will not get here
}
catch ( SecurityException e )
{
m_outError.println(
"Unable to locate a public static main method in class " + args[0] + ": " + e );
showUsage();
WrapperManager.stop( 1 );
return; // Will not get here
}
// Make sure that the method is public and static
int modifiers = m_mainMethod.getModifiers();
if ( !( Modifier.isPublic( modifiers ) && Modifier.isStatic( modifiers ) ) )
{
m_outError.println(
"The main method in class " + args[0] + " must be declared public and static." );
showUsage();
WrapperManager.stop( 1 );
return; // Will not get here
}
// Build the application args array
String[] appArgs = new String[args.length - 1];
System.arraycopy( args, 1, appArgs, 0, appArgs.length );
// Start the application. If the JVM was launched from the native
// Wrapper then the application will wait for the native Wrapper to
// call the application's start method. Otherwise the start method
// will be called immediately.
WrapperManager.start( this, appArgs );
// This thread ends, the WrapperManager will start the application after the Wrapper has
// been properly initialized by calling the start method above.
}
/*---------------------------------------------------------------
* Runnable Methods
*-------------------------------------------------------------*/
/**
* Used to launch the application in a separate thread.
*/
public void run()
{
// Notify the start method that the thread has been started by the JVM.
synchronized( this )
{
m_mainStarted = true;
notifyAll();
}
Throwable t = null;
try
{
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "invoking main method" );
}
m_mainMethod.invoke( null, new Object[] { m_appArgs } );
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "main method completed" );
}
synchronized(this)
{
// Let the start() method know that the main method returned, in case it is
// still waiting.
m_mainComplete = true;
this.notifyAll();
}
return;
}
catch ( IllegalAccessException e )
{
t = e;
}
catch ( IllegalArgumentException e )
{
t = e;
}
catch ( InvocationTargetException e )
{
t = e.getTargetException();
if ( t == null )
{
t = e;
}
}
// If we get here, then an error was thrown. If this happened quickly
// enough, the start method should be allowed to shut things down.
m_outInfo.println();
m_outError.println( "Encountered an error running main:" );
// We should print a stack trace here, because in the case of an
// InvocationTargetException, the user needs to know what exception
// their app threw.
t.printStackTrace( m_outError );
synchronized(this)
{
if ( m_startComplete )
{
// Shut down here.
WrapperManager.stop( 1 );
return; // Will not get here.
}
else
{
// Let start method handle shutdown.
m_mainComplete = true;
m_mainExitCode = new Integer( 1 );
this.notifyAll();
return;
}
}
}
/*---------------------------------------------------------------
* WrapperListener Methods
*-------------------------------------------------------------*/
/**
* The start method is called when the WrapperManager is signalled by the
* native wrapper code that it can start its application. This
* method call is expected to return, so a new thread should be launched
* if necessary.
* If there are any problems, then an Integer should be returned, set to
* the desired exit code. If the application should continue,
* return null.
*/
public Integer start( String[] args )
{
// Decide whether or not to wait for the start main method to complete before returning.
boolean waitForStartMain = WrapperSystemPropertyUtil.getBooleanProperty(
WrapperSimpleApp.class.getName() + ".waitForStartMain", false );
int maxStartMainWait = WrapperSystemPropertyUtil.getIntProperty(
WrapperSimpleApp.class.getName() + ".maxStartMainWait", 2 );
maxStartMainWait = Math.max( 1, maxStartMainWait );
// Decide the maximum number of times to loop waiting for the main start method.
int maxLoops;
if ( waitForStartMain )
{
maxLoops = Integer.MAX_VALUE;
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println(
"start(args) Will wait indefinitely for the main method to complete." );
}
}
else
{
maxLoops = maxStartMainWait; // 1s loops.
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "start(args) Will wait up to " + maxLoops
+ " seconds for the main method to complete." );
}
}
Thread mainThread = new Thread( this, "WrapperSimpleAppMain" );
synchronized(this)
{
m_appArgs = args;
mainThread.start();
// To avoid problems with the main thread starting slowly on heavily loaded systems,
// do not continue until the thread has actually started.
while ( !m_mainStarted )
{
try
{
this.wait( 1000 );
}
catch ( InterruptedException e )
{
// Continue.
}
}
// Wait for startup main method to complete.
int loops = 0;
while ( ( loops < maxLoops ) && ( !m_mainComplete ) )
{
try
{
this.wait( 1000 );
}
catch ( InterruptedException e )
{
// Continue.
}
if ( !m_mainComplete )
{
// If maxLoops is large then this could take a while. Notify the
// WrapperManager that we are still starting so it doesn't give up.
WrapperManager.signalStarting( 5000 );
}
loops++;
}
// Always set the flag stating that the start method completed. This is needed
// so the run method can decide whether or not it needs to be responsible for
// shutting down the JVM in the event of an exception thrown by the start main
// method.
m_startComplete = true;
// The main exit code will be null unless an error was thrown by the start
// main method.
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "start(args) end. Main Completed=" + m_mainComplete
+ ", exitCode=" + m_mainExitCode );
}
return m_mainExitCode;
}
}
/**
* Called when the application is shutting down.
*/
public int stop( int exitCode )
{
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "stop(" + exitCode + ")" );
}
// Normally an application will be asked to shutdown here. Standard Java applications do
// not have shutdown hooks, so do nothing here. It will be as if the user hit CTRL-C to
// kill the application.
return exitCode;
}
/**
* Called whenever the native wrapper code traps a system control signal
* against the Java process. It is up to the callback to take any actions
* necessary. Possible values are: WrapperManager.WRAPPER_CTRL_C_EVENT,
* WRAPPER_CTRL_CLOSE_EVENT, WRAPPER_CTRL_LOGOFF_EVENT, or
* WRAPPER_CTRL_SHUTDOWN_EVENT
*/
public void controlEvent( int event )
{
if ( ( event == WrapperManager.WRAPPER_CTRL_LOGOFF_EVENT )
&& ( WrapperManager.isLaunchedAsService() || WrapperManager.isIgnoreUserLogoffs() ) )
{
// Ignore
m_outInfo.println( "User logged out. Ignored." );
}
else
{
if ( WrapperManager.isDebugEnabled() )
{
m_outDebug.println( "controlEvent(" + event + ") Stopping" );
}
WrapperManager.stop( 0 );
// Will not get here.
}
}
/*---------------------------------------------------------------
* Methods
*-------------------------------------------------------------*/
/**
* Displays application usage
*/
protected void showUsage()
{
// Show this output without headers.
System.out.println();
System.out.println(
"WrapperSimpleApp Usage:" );
System.out.println(
" java org.tanukisoftware.wrapper.WrapperSimpleApp {app_class} [app_arguments]" );
System.out.println();
System.out.println(
"Where:" );
System.out.println(
" app_class: The fully qualified class name of the application to run." );
System.out.println(
" app_arguments: The arguments that would normally be passed to the" );
System.out.println(
" application." );
}
/*---------------------------------------------------------------
* Main Method
*-------------------------------------------------------------*/
/**
* Used to Wrapper enable a standard Java application. This main
* expects the first argument to be the class name of the application
* to launch. All remaining arguments will be wrapped into a new
* argument list and passed to the main method of the specified
* application.
*
* @param args Arguments passed to the application.
*/
public static void main( String args[] )
{
new WrapperSimpleApp( args );
}
}