Class Launcher

java.lang.Object

org.codehaus.plexus.classworlds.launcher.Launcher

Direct Known Subclasses:

Launcher

public class Launcher
extends Object

Command-line invokable application launcher.

This launcher class assists in the creation of classloaders and ClassRealms from a configuration file and the launching of the application's main method from the correct class loaded through the correct classloader.

The path to the configuration file is specified using the classworlds.conf system property, typically specified using the -D switch to java.

Author:

bob mcwhirter

Field Summary

Fields

Modifier and Type	Field	Description
protected static final String	CLASSWORLDS_CONF
protected String	mainClassName
protected String	mainRealmName
protected ClassLoader	systemClassLoader
protected static final String	UBERJAR_CONF_DIR
protected ClassWorld	world

Constructor Summary

Constructors

Constructor	Description
Launcher()

Method Summary

Modifier and Type	Method	Description
void	configure(InputStream is)	Configure from a file.
protected Method	getEnhancedMainMethod()	Retrieve the enhanced main entry method.
int	getExitCode()
Class<?>	getMainClass()	Retrieve the main entry class.
String	getMainClassName()
protected Method	getMainMethod()	Retrieve the main entry method.
ClassRealm	getMainRealm()	Retrieve the main entry realm.
String	getMainRealmName()
ClassLoader	getSystemClassLoader()
ClassWorld	getWorld()
void	launch(String[] args)	Launch the application.
protected void	launchEnhanced(String[] args)	Attempt to launch the application through the enhanced main method.
protected void	launchStandard(String[] args)	Attempt to launch the application through the standard main method.
static void	main(String[] args)	Launch the launcher from the command line.
static int	mainWithExitCode(String[] args)	Launch the launcher.
void	setAppMain(String mainClassName, String mainRealmName)
void	setSystemClassLoader(ClassLoader loader)
void	setWorld(ClassWorld world)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CLASSWORLDS_CONF

protected static final String CLASSWORLDS_CONF

See Also:

• Constant Field Values

UBERJAR_CONF_DIR

protected static final String UBERJAR_CONF_DIR

See Also:

• Constant Field Values

systemClassLoader

protected ClassLoader systemClassLoader

mainClassName

protected String mainClassName

mainRealmName

protected String mainRealmName

world

protected ClassWorld world

Constructor Details

Launcher

public Launcher()

Method Details

setSystemClassLoader

public void setSystemClassLoader(ClassLoader loader)

getSystemClassLoader

public ClassLoader getSystemClassLoader()

getExitCode

public int getExitCode()

setAppMain

public void setAppMain(String mainClassName,
 String mainRealmName)

getMainRealmName

public String getMainRealmName()

getMainClassName

public String getMainClassName()

setWorld

public void setWorld(ClassWorld world)

getWorld

public ClassWorld getWorld()

configure

public void configure(InputStream is)
               throws IOException,
ConfigurationException,
DuplicateRealmException,
NoSuchRealmException

Configure from a file.

Parameters:

is - The config input stream.

Throws:

IOException - If an error occurs reading the config file.

MalformedURLException - If the config file contains invalid URLs.

ConfigurationException - If the config file is corrupt.

DuplicateRealmException - If the config file defines two realms with the same id.

NoSuchRealmException - If the config file defines a main entry point in a non-existent realm.

getMainClass

public Class<?> getMainClass()
                      throws ClassNotFoundException,
NoSuchRealmException

Retrieve the main entry class.

Returns:

The main entry class.

Throws:

ClassNotFoundException - If the class cannot be found.

NoSuchRealmException - If the specified main entry realm does not exist.

getMainRealm

public ClassRealm getMainRealm()
                        throws NoSuchRealmException

Retrieve the main entry realm.

Returns:

The main entry realm.

Throws:

NoSuchRealmException - If the specified main entry realm does not exist.

getEnhancedMainMethod

protected Method getEnhancedMainMethod()
                                throws ClassNotFoundException,
NoSuchMethodException,
NoSuchRealmException

Retrieve the enhanced main entry method.

Returns:

The enhanced main entry method.

Throws:

ClassNotFoundException - If the main entry class cannot be found.

NoSuchMethodException - If the main entry method cannot be found.

NoSuchRealmException - If the main entry realm cannot be found.

getMainMethod

protected Method getMainMethod()
                        throws ClassNotFoundException,
NoSuchMethodException,
NoSuchRealmException

Retrieve the main entry method.

Returns:

The main entry method.

Throws:

ClassNotFoundException - If the main entry class cannot be found.

NoSuchMethodException - If the main entry method cannot be found.

NoSuchRealmException - If the main entry realm cannot be found.

launch

public void launch(String[] args)
            throws ClassNotFoundException,
IllegalAccessException,
InvocationTargetException,
NoSuchMethodException,
NoSuchRealmException

Launch the application.

Parameters:

args - The application args.

Throws:

ClassNotFoundException - If the main entry class cannot be found.

IllegalAccessException - If the method cannot be accessed.

InvocationTargetException - If the target of the invokation is invalid.

NoSuchMethodException - If the main entry method cannot be found.

NoSuchRealmException - If the main entry realm cannot be found.

launchEnhanced

protected void launchEnhanced(String[] args)
                       throws ClassNotFoundException,
IllegalAccessException,
InvocationTargetException,
NoSuchMethodException,
NoSuchRealmException

Attempt to launch the application through the enhanced main method.

This will seek a method with the exact signature of:

  public static void main(String[] args, ClassWorld world)
  

Parameters:

args - The application args.

Throws:

ClassNotFoundException - If the main entry class cannot be found.

IllegalAccessException - If the method cannot be accessed.

InvocationTargetException - If the target of the invokation is invalid.

NoSuchMethodException - If the main entry method cannot be found.

NoSuchRealmException - If the main entry realm cannot be found.

launchStandard

protected void launchStandard(String[] args)
                       throws ClassNotFoundException,
IllegalAccessException,
InvocationTargetException,
NoSuchMethodException,
NoSuchRealmException

Attempt to launch the application through the standard main method.

This will seek a method with the exact signature of:

  public static void main(String[] args)
  

Parameters:

args - The application args.

Throws:

ClassNotFoundException - If the main entry class cannot be found.

IllegalAccessException - If the method cannot be accessed.

InvocationTargetException - If the target of the invokation is invalid.

NoSuchMethodException - If the main entry method cannot be found.

NoSuchRealmException - If the main entry realm cannot be found.

main

public static void main(String[] args)

Launch the launcher from the command line. Will exit using System.exit with an exit code of 0 for success, 100 if there was an unknown exception, or some other code for an application error.

Parameters:

args - The application command-line arguments.

mainWithExitCode

public static int mainWithExitCode(String[] args)
                            throws Exception

Launch the launcher.

Parameters:

args - The application command-line arguments.

Returns:

an integer exit code

Throws:

Exception - If an error occurs.