org.gvsig.andami.plugins

Class PluginClassLoader

java.lang.Object

java.lang.ClassLoader

java.security.SecureClassLoader

java.net.URLClassLoader

org.gvsig.andami.plugins.PluginClassLoader

All Implemented Interfaces:

Closeable, AutoCloseable

public class PluginClassLoader
extends URLClassLoader

Class loader which loads the classes requested by the plugins. It first tries to search in the classpath, then it requests the class to the parent classloader, then it searches in the owns plugins' library dir, and if all these methods fail, it tries to load the class from any of the depended plugins. Finally, if this also fails, the other classloaders provided in the addLoaders method are requested to load the class.

The class loader can also be used to load resources from the plugin's directory by using the getResource() method.

Constructor Summary

Constructors

Constructor and Description
PluginClassLoader(URL[] jars, String baseDir, ClassLoader cl, List<PluginClassLoader> pluginLoaders)
PluginClassLoader(URL[] jars, String baseDir, ClassLoader cl, PluginClassLoader[] pluginLoaders) Creates a new PluginClassLoader object.

Method Summary

Modifier and Type	Method and Description
static void	addLoaders(ArrayList classLoaders) Adds other classloader to use when all the normal methods fail.
void	addPluginClassLoader(PluginClassLoader pluginClassLoader)
String	getBaseDir() Gets the plugin's base Iterator>dir, the directory which will be used to search resources.
protected PermissionCollection	getPermissions(CodeSource codesource)
String	getPluginName() Returns the name of the plugin (the name of the directory containing the plugin).
URL	getResource(String res) Gets the requested resource.
Enumeration<URL>	getResources(String name)
protected Enumeration<URL>	getResources(String name, HashSet<PluginClassLoader> visitedPlugins)
protected Class	loadClass(String name, boolean resolve) Carga la clase
protected Class	singleLoadClass(String name)
String	toString()

Methods inherited from class java.net.URLClassLoader

addURL, close, definePackage, findClass, findResource, findResources, 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, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, registerAsParallelCapable, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

PluginClassLoader

public PluginClassLoader(URL[] jars,
                         String baseDir,
                         ClassLoader cl,
                         PluginClassLoader[] pluginLoaders)
                  throws IOException

Creates a new PluginClassLoader object.

Parameters:

jars - Array with the search paths where classes will be searched

baseDir - Base directory for this plugin. This is the directory which will be used as basedir in the getResources method.

cl - The parent classloader of this classloader. It will be used to search classes before trying to search in the plugin's directory

pluginLoaders - The classloaders of the depended plugins.

Throws:

IOException

PluginClassLoader

public PluginClassLoader(URL[] jars,
                         String baseDir,
                         ClassLoader cl,
                         List<PluginClassLoader> pluginLoaders)
                  throws IOException

Throws:

IOException

Method Detail

singleLoadClass

protected Class singleLoadClass(String name)
                         throws ClassNotFoundException

Throws:

ClassNotFoundException

loadClass

protected Class loadClass(String name,
                          boolean resolve)
                   throws ClassNotFoundException

Carga la clase

Overrides:

loadClass in class ClassLoader

Parameters:

name - Nombre de la clase

resolve - Si se ha de resolver la clase o no

Returns:

Clase cargada

Throws:

ClassNotFoundException - Si no se pudo encontrar la clase

getResource

public URL getResource(String res)

Gets the requested resource. If the path is relative, its base directory will be the one provided in the PluginClassLoader's constructor. If the resource is not found, search in dependents plugins, otherwise the parent classloader will be invoked to try to get it. If it is not found, it will return null.

Overrides:

getResource in class ClassLoader

Parameters:

res - An absolute or relative path to the requested resource.

Returns:

Resource's URL if it was found, nul otherwise.

getResources

public Enumeration<URL> getResources(String name)
                              throws IOException

Overrides:

getResources in class ClassLoader

Throws:

IOException

getResources

protected Enumeration<URL> getResources(String name,
                                        HashSet<PluginClassLoader> visitedPlugins)
                                 throws IOException

Throws:

IOException

getPluginName

public String getPluginName()

Returns the name of the plugin (the name of the directory containing the plugin).

Returns:

An String containing the plugin's name.

getPermissions

protected PermissionCollection getPermissions(CodeSource codesource)

Overrides:

getPermissions in class URLClassLoader

getBaseDir

public String getBaseDir()

Gets the plugin's base Iterator>dir, the directory which will be used to search resources.

Returns:

Returns the baseDir.

addLoaders

public static void addLoaders(ArrayList classLoaders)

Adds other classloader to use when all the normal methods fail.

Parameters:

classLoaders - An ArrayList of ClassLoaders which will be used to load classes when all the normal methods fail.

toString

public String toString()

Overrides:

toString in class Object

addPluginClassLoader

public void addPluginClassLoader(PluginClassLoader pluginClassLoader)