dalvik.system
Class PathClassLoader

java.lang.Object
  java.lang.ClassLoader
      dalvik.system.PathClassLoader

public class PathClassLoader
extends ClassLoader

Simple ClassLoader implementation. This loads classes from a colon-separated list.

Constructor Summary

PathClassLoader(String path, ClassLoader parent)
Create a ClassLoader that finds files in the specified path.

PathClassLoader(String path, String libPath, ClassLoader parent)
Create a ClassLoader that finds files in the specified path.

Method Summary

protected Class<?>	findClass(String name) Find the class with the specified name.
protected String	findLibrary(String libname) Find a native library.
protected URL	findResource(String name) Returns an URL which can be used to access the resource described by resName, using the class loader's resource lookup algorithm.
protected Package	getPackage(String name) Returns package information for the given package.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findLoadedClass, findResources, findSystemClass, getPackages, getParent, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, loadClass, loadClass, resolveClass, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

PathClassLoader

public PathClassLoader(String path,
                       ClassLoader parent)

Create a ClassLoader that finds files in the specified path.

PathClassLoader

public PathClassLoader(String path,
                       String libPath,
                       ClassLoader parent)

Create a ClassLoader that finds files in the specified path. The path is a colon-separated list of files and directories. For Dalvik, this is usually a list of .jar and .apk filenames.

Parameters:

path - A colon-separated class path.

libPath - A colon-separated list of directories where native libraries can be found.

parent - The parent class loader.

Method Detail

findClass

protected Class<?> findClass(String name)
                      throws ClassNotFoundException

Find the class with the specified name. None of our ancestors were able to find it, so it's up to us now. "name" is a "binary name", e.g. "java.lang.String" or "java.net.URLClassLoader$3$1". This method will either return a valid Class object or throw an exception. Does not return null.

Overrides:

findClass in class ClassLoader

Parameters:

name - The name of the class to search for.

Returns:

The class or null.

Throws:

ClassNotFoundException - if the class cannot be found.

findResource

protected URL findResource(String name)

Description copied from class: ClassLoader

Returns an URL which can be used to access the resource described by resName, using the class loader's resource lookup algorithm. The default behavior is just to return null. This should be implemented by a ClassLoader.

Overrides:

findResource in class ClassLoader

Parameters:

name - The name of the resource to find.

Returns:

The location of the resource.

findLibrary

protected String findLibrary(String libname)

Find a native library. Return the full pathname of the first appropriate-looking file we find.

Overrides:

findLibrary in class ClassLoader

Parameters:

libname - The name of the library to find.

Returns:

The library file name or null.

getPackage

protected Package getPackage(String name)

Returns package information for the given package. Unfortunately, the PathClassLoader doesn't really have this information, and as a non-secure ClassLoader, it isn't even required to, according to the spec. Yet, we want to provide it, in order to make all those hopeful callers of myClass.getPackage().getName() happy. Thus we construct a Package object the first time it is being requested and fill most of the fields with dummy values. The Package object is then put into the ClassLoader's Package cache, so we see the same one next time. We don't create Package objects for null arguments or for the default package.

There a limited chance that we end up with multiple Package objects representing the same package: It can happen when when a package is scattered across different JAR files being loaded by different ClassLoaders. Rather unlikely, and given that this whole thing is more or less a workaround, probably not worth the effort.

Overrides:

getPackage in class ClassLoader

Parameters:

name - The name of the package to find

Returns:

The package requested, or null