org.quartz.classloading

Class CascadingClassLoadHelper

java.lang.Object

org.quartz.classloading.CascadingClassLoadHelper

All Implemented Interfaces:

ClassLoadHelper

public class CascadingClassLoadHelper
extends Object
implements ClassLoadHelper

A ClassLoadHelper uses all of the ClassLoadHelper types that are found in this package in its attempts to load a class, when one scheme is found to work, it is promoted to the scheme that will be used first the next time a class is loaded (in order to improve performance).

This approach is used because of the wide variance in class loader behavior between the various environments in which Quartz runs (e.g. disparate application servers, stand-alone, mobile devices, etc.). Because of this disparity, Quartz ran into difficulty with a one class-load style fits-all design. Thus, this class loader finds the approach that works, then 'remembers' it.

Author:

jhouse, pl47ypus

See Also:

ClassLoadHelper, LoadingLoaderClassLoadHelper, SimpleClassLoadHelper, ThreadContextClassLoadHelper, InitThreadContextClassLoadHelper

Constructor Summary

Constructors

Constructor and Description
CascadingClassLoadHelper()

Method Summary

Modifier and Type	Method and Description
ClassLoader	getClassLoader() Enable sharing of the "best" class-loader with 3rd party.
Set<Class<? extends Job>>	getJobClasses(String pkgname) Given a package name(s), search the classpath for all classes that extend sundial.job .
URL	getResource(String name) Finds a resource with a given name.
InputStream	getResourceAsStream(String name) Finds a resource with a given name.
void	initialize() Called to give the ClassLoadHelper a chance to initialize itself, including the opportunity to "steal" the class loader off of the calling thread, which is the thread that is initializing Quartz.
Class	loadClass(String name) Return the class with the given name.

Methods inherited from class java.lang.Object

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

Constructor Detail

CascadingClassLoadHelper

public CascadingClassLoadHelper()

Method Detail

initialize

public void initialize()

Called to give the ClassLoadHelper a chance to initialize itself, including the opportunity to "steal" the class loader off of the calling thread, which is the thread that is initializing Quartz.

Specified by:

initialize in interface ClassLoadHelper

loadClass

public Class loadClass(String name)
                throws ClassNotFoundException

Return the class with the given name.

Specified by:

loadClass in interface ClassLoadHelper

Parameters:

name - of the class to load.

Returns:

the requested class.

Throws:

ClassNotFoundException - if the class can be found in the classpath.

getResource

public URL getResource(String name)

Finds a resource with a given name. This method returns null if no resource with this name is found.

Specified by:

getResource in interface ClassLoadHelper

Parameters:

name - name of the desired resource

Returns:

a java.net.URL object

getResourceAsStream

public InputStream getResourceAsStream(String name)

Finds a resource with a given name. This method returns null if no resource with this name is found.

Specified by:

getResourceAsStream in interface ClassLoadHelper

Parameters:

name - name of the desired resource

Returns:

a java.io.InputStream object

getJobClasses

public Set<Class<? extends Job>> getJobClasses(String pkgname)

Given a package name(s), search the classpath for all classes that extend sundial.job . A comma(,) or colon(:) can be used to specify multiple packages to scan for Jobs.

Parameters:

pkgname -

Returns:

getClassLoader

public ClassLoader getClassLoader()

Enable sharing of the "best" class-loader with 3rd party.

Specified by:

getClassLoader in interface ClassLoadHelper

Returns:

the class-loader user be the helper.