com.izforge.izpack.util

Class Librarian

java.lang.Object

com.izforge.izpack.util.Librarian

All Implemented Interfaces:

CleanupClient

public class Librarian
extends Object
implements CleanupClient

This class handles loading of native libraries. There must only be one instance of Librarian per Java runtime, therefore this class is implemented as a 'Singleton'.

Librarian is capable of loading native libraries from a variety of different source locations. However, you should place your library files in the 'native' directory. The primary reason for supporting different source locations is to facilitate testing in a development environment, without the need to actually packing the application into a *.jar file.

Author:

Elmar Grom

Constructor Summary

Constructors

Constructor and Description
Librarian(TargetFactory factory, Housekeeper housekeeper) Constructs a Librarian.

Method Summary

Modifier and Type	Method and Description
void	cleanUp() This method attempts to remove all native libraries that have been temporarily created from the system.
protected URL	getResourcePath(String name) Returns the resource URL for the named library.
void	loadLibrary(String name, NativeLibraryClient client) Loads a library.

Methods inherited from class java.lang.Object

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

Constructor Detail

Librarian

public Librarian(TargetFactory factory,
                 Housekeeper housekeeper)

Constructs a Librarian.

Parameters:

factory - the factory

housekeeper - the house keeper

Method Detail

loadLibrary

public void loadLibrary(String name,
                        NativeLibraryClient client)
                 throws UnsatisfiedLinkError

Loads a library.

Parameters:

name - the library name

client - the native library client

Throws:

UnsatisfiedLinkError - if the library cannot be loaded

cleanUp

public void cleanUp()

This method attempts to remove all native libraries that have been temporarily created from the system. This method calls LibraryRemover which starts a new process which waits a little bit for exit of this process and tries than to delete the given files. If the version is 1.5.x or higher this process should be exit in one second, else the native libraries will be not deleted. Tests with the different methods produces hinds that the FreeLibraryAndExitThread (handle, 0) call in the dlls are the reason for VM crashes (version 1.5.x). May be this is a bug in the VM. But never seen a docu that this behavior is compatible with a VM. Since more than a year all 1.5 versions produce this crash. Therfore we make now a work around for it. But the idea to exit the thread for removing the file locking to give the possibility to delete the dlls are really nice. Therefore we use it with VMs which are compatible with it. (Klaus Bartz 2006.06.20)

Specified by:

cleanUp in interface CleanupClient

getResourcePath

protected URL getResourcePath(String name)

Returns the resource URL for the named library.

Parameters:

name - the library name

Returns:

the library's resource URL, or null if it is not found