org.ow2.proactive.resourcemanager.utils

Class AddonClassUtils

java.lang.Object

org.ow2.proactive.resourcemanager.utils.AddonClassUtils

public class AddonClassUtils
extends Object

This class helps the addon classes to use a child-first class loading mechanism for class loading and creating instances. Loading the addon class with a child-first delegation mechanims allows addons to use their specific version of dependent library.

Since:

03/12/19

Constructor Summary

Constructors

Constructor and Description
AddonClassUtils()

Method Summary

Modifier and Type	Method and Description
static ClassLoader	getAddonClassLoader(String addonClassName, ClassLoader originalClassLoader) Get the proper class loader for the class which could be an addon.
static Object	instantiateAddon(Class<?> addonClass) Create a new instance of the given class which could be an addon.
static boolean	isAddon(String addonFullClassName) Check whether the addon class should be loaded from addons jars.
static Class<?>	loadClass(String addonClassName, ClassLoader originalClassLoader) Load the class which could be an addon with the proper class loader.

Methods inherited from class java.lang.Object

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

Constructor Detail

AddonClassUtils

public AddonClassUtils()

Method Detail

isAddon

public static boolean isAddon(String addonFullClassName)

Check whether the addon class should be loaded from addons jars. The class is considered to be loaded from addons jar, iff server addons directory contains a directory named as addonName (addon simple class name in minuscule).

Parameters:

addonFullClassName - The complete class name of the addon

Returns:

whether the addon class should be loaded from addons jar

getAddonClassLoader

public static ClassLoader getAddonClassLoader(String addonClassName,
                                              ClassLoader originalClassLoader)

Get the proper class loader for the class which could be an addon. If the class is an addon, it should use its proper child-first class loader. Otherwise, the originalClassLoader is used. The created classloaders are stored and reused when asked for the same class next time.

Parameters:

addonClassName - The complete class name of the addon

originalClassLoader - The parent class loader of the addon class loader

Returns:

the proper class loader for the class

loadClass

public static Class<?> loadClass(String addonClassName,
                                 ClassLoader originalClassLoader)
                          throws ClassNotFoundException

Load the class which could be an addon with the proper class loader. If the class is an addon, the class loader is set as thread context class loader during class initialization.

Parameters:

addonClassName - the name of class to be loaded.

originalClassLoader - the original class loader used when the class is not an addon.

Returns:

the class object of given class name

Throws:

ClassNotFoundException - if the class can't be located

instantiateAddon

public static Object instantiateAddon(Class<?> addonClass)

Create a new instance of the given class which could be an addon. If the class is an addon, the class loader of addon class are injected as thread context class loader to the instance methods.

Parameters:

addonClass - the class object which could be an addon class

Returns:

a newly allocated instance of the given class