MAEPlugin
Class JarClassLoader

java.lang.Object
  |
  +--java.lang.ClassLoader
        |
        +--MAEPlugin.JarClassLoader

public class JarClassLoader

extends java.lang.ClassLoader

JarClassLoader provides a minimalistic ClassLoader which shows how to instantiate a class which resides in a .jar file.

This work was produced by Peter Lemkin of the National Cancer Institute, an agency of the United States Government. As a work of the United States Government there is no associated copyright. It is offered as open source software under the Mozilla Public License (version 1.1) subject to the limitations noted in the accompanying LEGAL file. This notice must be included with the code. The MAExplorer Mozilla and Legal files are available on http://maexplorer.sourceforge.net/.

Version:

1.0

Author:

John D. Mitchell, Non, Inc., Mar 3, 1999, Jai Evans 2002

See Also:

MAExplorer Home

Inner classes inherited from class java.lang.ClassLoader

java.lang.ClassLoader.NativeLibrary

Field Summary

private java.util.Hashtable	classes Contains the loaded classes
private char	classNameReplacementChar Utility Char
private JarResources	jarResources utility object that loads resources from a Jar

Fields inherited from class java.lang.ClassLoader

bootstrapClassPath, defaultDomain, defaultPermissions, domains, getClassLoaderPerm, initialized, loadedLibraryNames, nativeLibraries, nativeLibraryContext, nocerts, package2certs, packages, parent, scl, sclSet, sys_paths, systemNativeLibraries, usr_paths

Constructor Summary

JarClassLoader(java.io.File jarFile)
JarClassLoader() - constructor2 that loads jar from the path that is derived from the jarFile.

JarClassLoader(java.lang.String jarPath)
JarClassLoader() - default constructor that loads jar from the jarPath.

Method Summary

protected java.lang.String	formatClassName(java.lang.String className) formatClassName() - generate a name with ".class" extension
JarResources	getJarResources()
java.lang.Class	loadClass(java.lang.String className) loadClass() - load specified class and let it resolve the class if necessary.
java.lang.Class	loadClass(java.lang.String className, boolean resolveIt) loadClass() - load specified class
protected byte[]	loadClassBytes(java.lang.String className) loadClassBytes() loads bytes for class files.
void	setClassNameReplacementChar(char replacement) setClassNameReplacementChar() - remap class name.

Methods inherited from class java.lang.ClassLoader

, addClass, check, checkCerts, checkPackageAccess, compareCerts, defineClass, defineClass, defineClass, defineClass0, definePackage, findBootstrapClass, findBootstrapClass0, findClass, findLibrary, findLoadedClass, findNative, findResource, findResources, findSystemClass, getBootstrapClassPath, getBootstrapResource, getBootstrapResources, getCallerClassLoader, getDefaultDomain, getGetClassLoaderPerm, getPackage, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, initializePath, isAncestor, loadClassInternal, loadLibrary, loadLibrary0, resolveClass, resolveClass0, setSigners

Methods inherited from class java.lang.Object

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

Field Detail

jarResources

private JarResources jarResources

utility object that loads resources from a Jar

classes

private java.util.Hashtable classes

Contains the loaded classes

classNameReplacementChar

private char classNameReplacementChar

Utility Char

Constructor Detail

JarClassLoader

public JarClassLoader(java.lang.String jarPath)

JarClassLoader() - default constructor that loads jar from the jarPath.

Parameters:

jarPath - is the path of the Jar file

JarClassLoader

public JarClassLoader(java.io.File jarFile)

JarClassLoader() - constructor2 that loads jar from the path that is derived from the jarFile. [constructor 2]

Parameters:

jarFile - is the Jar file.

Method Detail

loadClassBytes

protected byte[] loadClassBytes(java.lang.String className)

loadClassBytes() loads bytes for class files. Note: the class may be buried inside of a directory E.g. Plugins/className, so we need to test that first.

Parameters:

className - of class to load bytes from

Returns:

byte array of data from the class

loadClass

public java.lang.Class loadClass(java.lang.String className)
                          throws java.lang.ClassNotFoundException

loadClass() - load specified class and let it resolve the class if necessary. This is a simple version for external clients since they will always want the class resolved before it is returned to them.

Overrides:

loadClass in class java.lang.ClassLoader

Parameters:

className - name of the class to load

Returns:

class that was loaded or null if error

Throws:

java.lang.ClassNotFoundException -

loadClass

public java.lang.Class loadClass(java.lang.String className,
                                 boolean resolveIt)
                          throws java.lang.ClassNotFoundException

loadClass() - load specified class

Overrides:

loadClass in class java.lang.ClassLoader

Parameters:

className - name of the class to load

resolveIt - lets it resolve the class if necessary

Returns:

class that was loaded or null if error

Throws:

java.lang.ClassNotFoundException -

setClassNameReplacementChar

public void setClassNameReplacementChar(char replacement)

setClassNameReplacementChar() - remap class name. This optional call allows a class name such as "COM.test.Hello" to be changed to "COM_test_Hello", which is useful for storing classes from different packages in the same retrival directory. In the above example the char would be '_'.

Parameters:

replacement - character to assign.

formatClassName

protected java.lang.String formatClassName(java.lang.String className)

formatClassName() - generate a name with ".class" extension

Parameters:

className - class name

Returns:

formated class name

getJarResources

public JarResources getJarResources()