Browse Prior Art Database

Improved Process for Visual Development of Client/Server Programs

IP.com Disclosure Number: IPCOM000122848D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 4 page(s) / 154K

Publishing Venue

IBM

Related People

Li, Z: AUTHOR

Abstract

JavaBeans is quickly accepted as a promising component model. IBM* Visual Age for Java provides various tools supporting beans development. One portion of the tools is the support for developing enterprise Java bean applications. The tool allows the user to visually develop distributed beans applications without writing communication code.

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Improved Process for Visual Development of Client/Server Programs

      JavaBeans is quickly accepted as a promising component
model.  IBM* Visual Age for Java provides various tools supporting
beans development.  One portion of the tools is the support for
developing enterprise Java bean applications.  The tool allows the
user to visually  develop distributed beans applications without
writing communication code.

      The Visual Age approach is to generate the proxy beans from
users designated server beans and then link the generated proxy beans
with the client beans in a visual environment.  However, this
approach has two notable drawbacks.  First, the users have to deal
with the system  generated classes which they may not be comfortable
with.  In addition,  there are a large number of the generated
classes.  For example, there  are eight generated classes and two
generated interfaces in the simple  example provided with Visual Age
for Java.  Second, the users have to link the client proxy bean first
and then test the correctness of their  program.  If there are
something wrong, the users have to repeat the whole development
process.

      The following process is proposed to allow a Java bean
application built in a visual environment and run remotely without
the above two problems.

      The improved process can be summarized as follows.  Users link
their client bean with the server bean first in their visual
environment such as Visual Age.  A tool can then generate the client
and the server  proxy beans and allow the client bean to interact
with the client proxy  bean, and let client proxy bean talk with the
server proxy bean using such as Remote Method Invocation (RMI).  The
user beans will not need to be changed.  Next described is one
approach of constructing this proxy generation tool.

      The tool for generating the proxy beans can be built by using
Javabeans' introspection and Java's reflection facilities.  For
example, in CR-xxx, we described a process to dynamically split a
Java program and run it as a client/server application, which
includes a process of  generating proxy classes using reflection.
For JavaBeans, the introspection is needed if users do not use the
design pattern in the event handling code.  Moreover, the following
two problems must be solved in generating proxy bean classes: the
name conflicts and event handling.  The following examples are used
to describe the problems and  this solution.

      Assume that there are two beans X and Y.  The class Y and its
objects will be placed in a remote machine and the class X and its
objects are in the local machine.  X is a listener to a property
propY in Y.  When X is notified the changes of propY, it will call a
method B defined in Y.
  public Class X implements java.beans.PropertyChangeListener {
    private Y y = new Y();
    // register as a listener
    public X() {
      y.addPropertyChange...