Package javassist.tools.web

Class Viewer

java.lang.Object

java.lang.ClassLoader

javassist.tools.web.Viewer

public class Viewer
extends ClassLoader

A sample applet viewer.

This is a sort of applet viewer that can run any program even if the main class is not a subclass of Applet. This viewwer first calls main() in the main class.

To run, you should type:

% java javassist.tools.web.Viewer host port Main arg1, ...

This command calls Main.main() with arg1,... All classes including Main are fetched from a server http://host:port. Only the class file for Viewer must exist on a local file system at the client side; even other javassist.* classes are not needed at the client side. Viewer uses only Java core API classes.

Note: since a Viewer object is a class loader, a program loaded by this object can call a method in Viewer. For example, you can write something like this:

 Viewer v = (Viewer)this.getClass().getClassLoader();
 String port = v.getPort();
 

Constructor Summary

Constructors

Constructor	Description
Viewer(String host, int p)	Constructs a viewer.

Method Summary

Modifier and Type	Method	Description
protected byte[]	fetchClass(String classname)	Fetches the class file of the specified class from the http server.
protected Class<?>	findClass(String name)	Finds the specified class.
int	getPort()	Returns the port number.
String	getServer()	Returns the server name.
protected Class<?>	loadClass(String name, boolean resolve)	Requests the class loader to load a class.
static void	main(String[] args)	Starts a program.
void	run(String classname, String[] args)	Invokes main() in the class specified by classname.

Methods inherited from class java.lang.ClassLoader

clearAssertionStatus, defineClass, defineClass, defineClass, defineClass, definePackage, findClass, findLibrary, findLoadedClass, findResource, findResource, findResources, findSystemClass, getClassLoadingLock, getDefinedPackage, getDefinedPackages, getName, getPackage, getPackages, getParent, getPlatformClassLoader, getResource, getResourceAsStream, getResources, getSystemClassLoader, getSystemResource, getSystemResourceAsStream, getSystemResources, getUnnamedModule, isRegisteredAsParallelCapable, loadClass, registerAsParallelCapable, resolveClass, resources, setClassAssertionStatus, setDefaultAssertionStatus, setPackageAssertionStatus, setSigners

Methods inherited from class java.lang.Object

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

Constructor Detail

Viewer

public Viewer(String host,
              int p)

Constructs a viewer.

Parameters:

host - server name

p - port number

Method Detail

main

public static void main(String[] args)
                 throws Throwable

Starts a program.

Throws:

Throwable

getServer

public String getServer()

Returns the server name.

getPort

public int getPort()

Returns the port number.

run

public void run(String classname,
                String[] args)
         throws Throwable

Invokes main() in the class specified by classname.

Parameters:

classname - executed class

args - the arguments passed to main().

Throws:

Throwable

loadClass

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

Requests the class loader to load a class.

Overrides:

loadClass in class ClassLoader

Throws:

ClassNotFoundException

findClass

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

Finds the specified class. The implementation in this class fetches the class from the http server. If the class is either java.*, javax.*, or Viewer, then it is loaded by the parent class loader.

This method can be overridden by a subclass of Viewer.

Overrides:

findClass in class ClassLoader

Throws:

ClassNotFoundException

fetchClass

protected byte[] fetchClass(String classname)
                     throws Exception

Fetches the class file of the specified class from the http server.

Throws:

Exception