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* The AIBench Shell Plugin
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* This file is part of the BeanShell Java Scripting distribution. *
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* Sun Public License Notice: *
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* Patrick Niemeyer ([email protected]) *
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package bsh.classpath;
import java.net.URL;
import java.net.URLClassLoader;
import bsh.BshClassManager;
/**
* One of the things BshClassLoader does is to address a deficiency in
* URLClassLoader that prevents us from specifying individual classes via URLs.
*/
public class BshClassLoader extends URLClassLoader {
BshClassManager classManager;
/**
* @param classManager
* the class manager.
* @param bases
* URLs JARClassLoader seems to require absolute paths
*/
public BshClassLoader(BshClassManager classManager, URL[] bases) {
super(bases);
this.classManager = classManager;
}
/**
* @param classManager
* the class manager.
* @param bcp
* the BeanShell class path.
*/
public BshClassLoader(BshClassManager classManager, BshClassPath bcp) {
this(classManager, bcp.getPathComponents());
}
/**
* For use by children
*
* @param classManager
* the class manager.
*/
protected BshClassLoader(BshClassManager classManager) {
this(classManager, new URL[] {});
}
// public version of addURL
public void addURL(URL url) {
super.addURL(url);
}
/**
* This modification allows us to reload classes which are in the Java VM
* user classpath. We search first rather than delegate to the parent
* classloader (or bootstrap path) first.
*
* An exception is for BeanShell core classes which are always loaded from
* the same classloader as the interpreter.
*
* @param name
* the name of the class to load.
* @param resolve
* whether the class should be resolved or not.
* @return the class loaded.
* @throws ClassNotFoundException
* if the class could not be found.
*/
public Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
Class c = null;
/*
* Check first for classes loaded through this loader. The VM will not
* allow a class to be loaded twice.
*/
c = findLoadedClass(name);
if (c != null)
return c;
// This is copied from ClassManagerImpl
// We should refactor this somehow if it sticks around
if (name.startsWith(ClassManagerImpl.BSH_PACKAGE))
try {
return bsh.Interpreter.class.getClassLoader().loadClass(name);
} catch (ClassNotFoundException e) {}
/*
* Try to find the class using our classloading mechanism. Note: I wish
* we didn't have to catch the exception here... slow
*/
try {
c = findClass(name);
} catch (ClassNotFoundException e) {}
if (c == null)
throw new ClassNotFoundException("here in loaClass");
if (resolve)
resolveClass(c);
return c;
}
/**
* Find the correct source for the class...
*
* Try designated loader if any Try our URLClassLoader paths if any Try base
* loader if any Try system ???
*
* @param name
* the name of a class.
* @return the class.
* @throws ClassNotFoundException
* if the class could not be found.
*/
// add some caching for not found classes?
protected Class findClass(String name) throws ClassNotFoundException {
// Deal with this cast somehow... maybe have this class use
// ClassManagerImpl type directly.
// Don't add the method to BshClassManager... it's really an
// impl thing
ClassManagerImpl bcm = (ClassManagerImpl) getClassManager();
// Should we try to load the class ourselves or delegate?
// look for overlay loader
// Deal with this cast somehow... maybe have this class use
// ClassManagerImpl type directly.
// Don't add the method to BshClassManager... it's really an
// impl thing
ClassLoader cl = bcm.getLoaderForClass(name);
Class c;
// If there is a designated loader and it's not us delegate to
// it
if (cl != null && cl != this)
try {
return cl.loadClass(name);
} catch (ClassNotFoundException e) {
throw new ClassNotFoundException("Designated loader could not find class: " + e);
}
// Let URLClassLoader try any paths it may have
if (getURLs().length > 0)
try {
return super.findClass(name);
} catch (ClassNotFoundException e) {
// System.out.println(
// "base loader here caught class not found:
// "+name );
}
// If there is a baseLoader and it's not us delegate to it
cl = bcm.getBaseLoader();
if (cl != null && cl != this)
try {
return cl.loadClass(name);
} catch (ClassNotFoundException e) {}
// Try system loader
return bcm.plainClassForName(name);
}
/*
* The superclass does something like this
*
* c = findLoadedClass(name); if null try if parent not null c =
* parent.loadClass(name, false); else c = findBootstrapClass(name); catch
* ClassNotFoundException c = findClass(name);
*/
BshClassManager getClassManager() {
return classManager;
}
}
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