org.apache.sling.launchpad.base.shared

Class Loader

java.lang.Object

org.apache.sling.launchpad.base.shared.Loader

public class Loader
extends Object

The Loader class provides utility methods for the actual launchers to help launching the framework.

Constructor Summary

Constructors

Constructor and Description
Loader(File launchpadHome) Creates a loader instance to load from the given launchpad home folder.

Method Summary

Modifier and Type	Method and Description
void	cleanupVM() Tries to remove as many traces of class loaded by the framework from the Java VM as possible.
protected void	info(String msg) Meant to be overridden to display or log info
boolean	installLauncherJar(URL launcherJar) Copies the contents of the launcher JAR as indicated by the URL to the sling home directory.
Object	loadLauncher(String launcherClassName) Creates an URLClassLoader from a _launcher JAR_ file in the given launchpadHome directory and loads and returns the launcher class identified by the launcherClassName.
static void	spool(InputStream ins, File destFile) Spools the contents of the input stream to the given file replacing the contents of the file with the contents of the input stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

Loader

public Loader(File launchpadHome)

Creates a loader instance to load from the given launchpad home folder. Besides ensuring the existence of the launchpad home folder, the constructor also removes all but the most recent launcher JAR files from the Sling home folder (thus cleaning up from previous upgrades).

Parameters:

launchpadHome - The launchpad home folder. This must not be null or an empty string.

Throws:

IllegalArgumentException - If the launchpadHome argument is null or an empty string or if the launchpad home folder exists but is not a directory or if the Sling home folder cannot be created.

Method Detail

loadLauncher

public Object loadLauncher(String launcherClassName)

Creates an URLClassLoader from a _launcher JAR_ file in the given launchpadHome directory and loads and returns the launcher class identified by the launcherClassName.

Parameters:

launcherClassName - The fully qualified name of a class implementing the Launcher interface. This class must have a public constructor taking no arguments.

Returns:

the Launcher instance loaded from the newly created classloader

Throws:

NullPointerException - if launcherClassName is null

IllegalArgumentException - if the launcherClassName cannot be instantiated. The cause of the failure is contained as the cause of the exception.

cleanupVM

public void cleanupVM()

Tries to remove as many traces of class loaded by the framework from the Java VM as possible. Most notably the following traces are removed:

• JavaBeans property caches
• Close the Launcher Jar File (if opened by the platform)

This method must be called when the notifier is called.

installLauncherJar

public boolean installLauncherJar(URL launcherJar)
                           throws IOException

Copies the contents of the launcher JAR as indicated by the URL to the sling home directory. If the existing file is is a more recent bundle version than the supplied launcher JAR file, it is is not replaced.

Returns:

true if the launcher JAR file has been installed or updated, false otherwise.

Throws:

IOException - If an error occurrs transferring the contents

spool

public static void spool(InputStream ins,
                         File destFile)
                  throws IOException

Spools the contents of the input stream to the given file replacing the contents of the file with the contents of the input stream. When this method returns, the input stream is guaranteed to be closed.

Throws:

IOException - If an error occurrs reading or writing the input stream contents.

info

protected void info(String msg)

Meant to be overridden to display or log info