Browse Prior Art Database

Screen Handler Components

IP.com Disclosure Number: IPCOM000123393D
Original Publication Date: 1998-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 7 page(s) / 526K

Publishing Venue

IBM

Related People

Griffin, C: AUTHOR

Abstract

Disclosed is a method for using Java (*) Beans to map between CICS (**) 3270 screens and a Java user interface without programming. The Java Beans allow a user who has little knowledge of CICS or Java to create a Java applet that can act as a web front-end to existing CICS 3270 applications.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 43% of the total text.

Screen Handler Components

   Disclosed is a method for using Java (*) Beans to map
between CICS (**) 3270 screens and a Java user interface without
programming.  The Java Beans allow a user who has little knowledge
of CICS or Java to create a Java applet that can act as a web
front-end to existing CICS 3270 applications.

   Many users want to use the CICS External Programming
Interface (EPI) to front-end existing CICS 3270 applications, but
find that the EPI is complex and difficult to use.  The latest
version of CICS Gateway for Java includes high-level interfaces to
the EPI which make programming easier.  These interfaces are
implemented as classes.  However, the provision of such classes
alone is not sufficient for an application developer using a visual
builder such as IBM's VisualAge or the like to develop applications.
Such a developer does not wish to write code, but only to employ
these classes in a truly object-oriented fashion.  The proposed
solution is to create two Java Beans that facilitate visual
connection between an applet and a CICS server:
  o  EPITerminal, which sends and receives 3270 data, provides
     the connection to the underlying CICS terminal, through the
     CICS Java Gateway.  In order to deal with the data arriving
     from CICS, the user attaches to EPITerminal further beans,
     called Screenhandlers.  When data arrives from CICS,
     EPITerminal notifies all its ScreenHandlers.  In addition,
     the EPITerminal assumes responsiblity for ensuring that
     the CICS terminal is driven correctly and is disconnected
     properly after use.  This is necessary because while the
     user interface is asynchronous (any action at any time),
     the CICS 3270 terminal must always be driven synchronously
     (each action must be completed before the next request is
     submitted).
  o  EPIBasicScreenHandler is a generic ScreenHandler that deals
     with CICS screens by displaying a roughly equivalent panel
     of user interface components - static text and entry fields.
     It allows a user to modify the screen and send it back to
     CICS.

   A simple applet using these two beans can present similar
functionality to the CICS Internet Gateway, i.e: a simple general
front-end that can be used without modification to give access to
CICS from the Web.  In more detail, the EPITerminal Bean has a
number of properties, such as Java Gateway settings for connecting
to the CICS Gateway for Java, terminal definition settings, and
transaction settings.  Also defined are the events that can be
received by registered listeners, for example, the
"terminalConnected" event when the terminal has connected to CICS, or
the "handleScreen" event when the terminal receives a screen from
CICS.

   The methods exposed by EPITerminal for use by a developer
using the beans in a visual development tool such as VisualAge for
Java include "connect()" ...