gate.util

Class GateClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

gate.util.GateClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable

public class GateClassLoader
extends URLClassLoader

GATE's class loader, which allows loading of classes over the net. A list of URLs is searched, which should point at .jar files or to directories containing class file hierarchies. The loader is also used for creating JAPE RHS action classes.

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.apache.log4j.Logger	log

Constructor Summary

Constructors

Constructor and Description
GateClassLoader(String name) Default construction - use an empty URL list.
GateClassLoader(String name, ClassLoader parent) Chaining constructor.
GateClassLoader(String name, URL[] urls) Default construction with URLs list.
GateClassLoader(String name, URL[] urls, ClassLoader parent) Chaining constructor with URLs list.
GateClassLoader(String name, URL[] urls, ClassLoader parent, boolean isolated)

Method Summary

Methods

Modifier and Type	Method and Description
void	addURL(URL url) Appends the specified URL to the list of URLs to search for classes and resources.
Class<?>	defineGateClass(String name, byte[] bytes, int offset, int len) Forward a call to super.defineClass, which is protected and final in super.
Class<?>	findExistingClass(String name) Given a fully qualified class name, this method returns the instance of Class if it is already loaded using the ClassLoader or it returns null.
void	forgetClassLoader(GateClassLoader classloader) Causes the specified classloader to be forgotten, making it and all the class definitions loaded by it available for garbage collection
void	forgetClassLoader(String id) Causes the specified classloader to be forgotten, making it and all the class definitions loaded by it available for garbage collection
void	forgetClassLoader(String id, Gate.DirectoryInfo dInfo)
List<GateClassLoader>	getChildren() Get the child classloaders in creation order.
GateClassLoader	getDisposableClassLoader(String id) Returns a classloader that can, at some point in the future, be forgotton which allows the class definitions to be garbage collected.
GateClassLoader	getDisposableClassLoader(String id, boolean isolated)
GateClassLoader	getDisposableClassLoader(String id, ClassLoader parent, boolean isolated)
String	getID()
URL	getResource(String name)
boolean	isIsolated()
Class<?>	loadClass(String name)
Class<?>	loadClass(String name, boolean resolve) Delegate loading to the super class (loadClass has protected access there).
void	resolveGateClass(Class<?> c) Forward a call to super.resolveClass, which is protected and final in super.
String	toString()

Methods inherited from class java.net.URLClassLoader

close, definePackage, findClass, findResource, findResources, getPermissions, getResourceAsStream, getURLs, newInstance, newInstance

Methods inherited from class java.security.SecureClassLoader

defineClass, defineClass

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLibrary, findLoadedClass, findSystemClass, getClassLoadingLock, getPackage, getPackages, getParent, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Field Detail

log

protected static final org.apache.log4j.Logger log

Constructor Detail

GateClassLoader

public GateClassLoader(String name)

Default construction - use an empty URL list.

GateClassLoader

public GateClassLoader(String name,
               ClassLoader parent)

Chaining constructor.

GateClassLoader

public GateClassLoader(String name,
               URL[] urls)

Default construction with URLs list.

GateClassLoader

public GateClassLoader(String name,
               URL[] urls,
               ClassLoader parent)

Chaining constructor with URLs list.

GateClassLoader

public GateClassLoader(String name,
               URL[] urls,
               ClassLoader parent,
               boolean isolated)

Method Detail

getID

public String getID()

isIsolated

public boolean isIsolated()

toString

public String toString()

Overrides:

toString in class Object

addURL

public void addURL(URL url)

Appends the specified URL to the list of URLs to search for classes and resources.

Overrides:

addURL in class URLClassLoader

getResource

public URL getResource(String name)

Overrides:

getResource in class ClassLoader

loadClass

public Class<?> loadClass(String name)
                   throws ClassNotFoundException

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

loadClass

public Class<?> loadClass(String name,
                 boolean resolve)
                   throws ClassNotFoundException

Delegate loading to the super class (loadClass has protected access there).

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

defineGateClass

public Class<?> defineGateClass(String name,
                       byte[] bytes,
                       int offset,
                       int len)

Forward a call to super.defineClass, which is protected and final in super. This is used by JAPE and the Jdk compiler class.

resolveGateClass

public void resolveGateClass(Class<?> c)

Forward a call to super.resolveClass, which is protected and final in super. This is used by JAPE and the Jdk compiler class

findExistingClass

public Class<?> findExistingClass(String name)

Given a fully qualified class name, this method returns the instance of Class if it is already loaded using the ClassLoader or it returns null.

getDisposableClassLoader

public GateClassLoader getDisposableClassLoader(String id)

Returns a classloader that can, at some point in the future, be forgotton which allows the class definitions to be garbage collected.

Parameters:

id - the id of the classloader to return

Returns:

either an existing classloader with the given id or a new classloader

getDisposableClassLoader

public GateClassLoader getDisposableClassLoader(String id,
                                       boolean isolated)

getDisposableClassLoader

public GateClassLoader getDisposableClassLoader(String id,
                                       ClassLoader parent,
                                       boolean isolated)

forgetClassLoader

public void forgetClassLoader(String id)

Causes the specified classloader to be forgotten, making it and all the class definitions loaded by it available for garbage collection

Parameters:

id - the id of the classloader to forget

forgetClassLoader

public void forgetClassLoader(GateClassLoader classloader)

Causes the specified classloader to be forgotten, making it and all the class definitions loaded by it available for garbage collection

Parameters:

classloader - the classloader to forget

forgetClassLoader

public void forgetClassLoader(String id,
                     Gate.DirectoryInfo dInfo)

getChildren

public List<GateClassLoader> getChildren()

Get the child classloaders in creation order. Note that you shouldn't have any need to access the child classloaders. Holding references is very likely to lead to a memory leak as the plugins will no longer be disposable. YOU HAVE BEEN WARNED!

Returns:

the child classloaders in creation order