Introduction to WebT

This chapter describes the basic features and roles of WebT which supports transaction services for Tmax and Java application programs.

1. Overview

Tmax is a middleware product that operates in a client/server environment. Web Transaction (WebT) supports transaction services between Tmax and Java application programs. WebT is distributed as an API library. It is used by Web Application Server (WAS) products that operate in a web-based environment such as JEUS. It is designed to provide dynamic data services using the transaction handling and load balancing features of Tmax in a web environment.

The following figure shows the service flow between WebT and Tmax. If a client sends a request, the server program of Tmax is executed through the WebT module and then the service will run.

figure 1
Figure 1. Service Flow between WebT and Tmax

2. WebTConnectionPool

In order to efficiently manage Tmax connections, WebT provides a class called WebTConnectionPool. WebTConnectionPool does not create a new connection object whenever a Tmax service is requested, but reuses an old object that was previously used. By doing this, resources and time that are spent to set and close network connections for a Tmax server can be saved.

A WebTConnectionPool consists of one WebTConnectionGroup or more, and each WebTConnectionGroup connects to one Tmax server. A client program can be connected to a Tmax server using the name of a WebTConnectionGroup.

If a WebT module links with JEUS, a JEUS container manages a WebTConnectionPool. The JEUS container creates a connection pool by using the WebT properties configuration file or JEUS configuration file and automatically returns a non-returned connection to the connection pool.

3. WebT-Server System

A WebT-Server system exists between a Tmax system and JEUS. It enables a Tmax client to call a EJB service of JEUS.

The following figure shows how an EJB service is called through a WebT-Server system.

figure 3
Figure 2. WebT-Server System

A WebT-Server system consists of the following modules:

  • JAVA GW

    Processes service requests sent from Tmax to JEUS.

  • JTmax

    A daemon in JEUS that receives a Tmax service request.

  • WebT Library

    Processes data that is exchanged between Tmax and JEUS.

  • Monitoring Library

    A library that supports the console administrator tool and WebAdmin in JEUS 7.0 Fix#1. It consists of the following two files: webt-jeus7-webadmin-plugin.jar and jext_webt_command_patch.jar.

  • Unix Domain Socket Library

    A library that enables Unix Domain Socket communication across machines (nodes) using the same client, supported in Webt 7.1 or later. The file is libwebt.so.

  • Other Utility

    A library to start up WebT without JEUS. The file is webtutil.jar, which provides a package of classes for using WebT in jeus.jar and jeusutil.jar.