Package javassist.tools.web

Class Viewer

  • public class Viewer
extends java.lang.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();

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int port  
      private java.lang.String server  

    • Constructor Summary

      Constructors 
      Constructor Description
      Viewer​(java.lang.String host, int p)
      Constructs a viewer.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected byte[] fetchClass​(java.lang.String classname)
      Fetches the class file of the specified class from the http server.
      protected java.lang.Class<?> findClass​(java.lang.String name)
      Finds the specified class.
      int getPort()
      Returns the port number.
      java.lang.String getServer()
      Returns the server name.
      protected java.lang.Class<?> loadClass​(java.lang.String name, boolean resolve)
      Requests the class loader to load a class.
      static void main​(java.lang.String[] args)
      Starts a program.
      private byte[] readStream​(java.io.InputStream fin)  
      void run​(java.lang.String classname, java.lang.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

    • Field Detail

      • server

        private java.lang.String server

      • port

        private int port

    • Constructor Detail

      • Viewer

        public Viewer​(java.lang.String host,
              int p)
        Constructs a viewer.
        Parameters:
        host - server name
        p - port number

    • Method Detail

      • main

        public static void main​(java.lang.String[] args)
                 throws java.lang.Throwable
        Starts a program.
        Throws:
        java.lang.Throwable

      • getServer

        public java.lang.String getServer()
        Returns the server name.

      • getPort

        public int getPort()
        Returns the port number.

      • run

        public void run​(java.lang.String classname,
                java.lang.String[] args)
         throws java.lang.Throwable
        Invokes main() in the class specified by classname.
        Parameters:
        classname - executed class
        args - the arguments passed to main().
        Throws:
        java.lang.Throwable

      • loadClass

        protected java.lang.Class<?> loadClass​(java.lang.String name,
                                       boolean resolve)
                                throws java.lang.ClassNotFoundException
        Requests the class loader to load a class.
        Overrides:
        loadClass in class java.lang.ClassLoader
        Throws:
        java.lang.ClassNotFoundException

      • findClass

        protected java.lang.Class<?> findClass​(java.lang.String name)
                                throws java.lang.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 java.lang.ClassLoader
        Throws:
        java.lang.ClassNotFoundException

      • fetchClass

        protected byte[] fetchClass​(java.lang.String classname)
                     throws java.lang.Exception
        Fetches the class file of the specified class from the http server.
        Throws:
        java.lang.Exception

      • readStream

        private byte[] readStream​(java.io.InputStream fin)
                   throws java.io.IOException
        Throws:
        java.io.IOException