Introducing BEA Jolt

 

BEA Jolt is a Java-based interface to the BEA Tuxedo system that extends the functionality of existing Tuxedo applications to include Intranet- and Internet-wide availability. Using Jolt, you can now easily transform any Tuxedo application so that its services are available to customers using an ordinary browser on the Internet. Jolt interfaces with existing and new Tuxedo applications and services to allow secure, scalable, Intranet/Internet transactions between client and server. Jolt allows you to build client applications and applets that can remotely invoke existing BEA Tuxedo services, allowing application messaging, component management, and distributed transaction processing.

Since these tasks are done in the Jolt API and the Jolt Repository Editor using the Java programming language, the Jolt documentation assumes a familiarity with BEA Tuxedo and Java programming. This documentation is intended for system administrators, network administrators and developers.

"Introducing BEA Jolt" covers the following topics:

• What is BEA Jolt?

• Key Features

• How It Works

  • Jolt Servers

  • Jolt Class Library

  • JoltBeans

  • ASP Connectivity for Tuxedo

  • Jolt Server and Jolt Client Communication

  • Jolt Repository

  • Jolt Internet Relay

What is BEA Jolt?

BEA Jolt is a Java class library and API that provides an interface to BEA Tuxedo and WLE from remote Java clients. BEA Jolt consists of several components for creating Java-based client programs that access Tuxedo services. These Jolt components are as follows:

• Jolt Servers-One or more Jolt servers listen for network connections from clients, translate Jolt messages, multiplex multiple clients into a single process, and submit and retrieve requests to and from Tuxedo-based applications running on one or more Tuxedo servers.

• Jolt Class Library-The Jolt class library is a Java package containing the class files that implement the Jolt API. These classes enable Java applications and applets to invoke BEA Tuxedo services. The Jolt class library includes functionality to set, retrieve, manage and invoke communication attributes, notifications, network connections, transactions, and services.

• JoltBeans-BEA JoltBeans provides a JavaBeans compliant interface to BEA Jolt. JoltBeans are Beans components that can be used in JavaBeans-enabled Integrated Development Environments (IDEs) to construct BEA Jolt clients. Jolt Beans consists of two sets of Java Beans: JoltBeans toolkit (a JavaBeans-compliant interface to BEA Jolt that includes the JoltServiceBean, JoltSessionBean, and JoltUserEventBean) and Jolt GUI beans (which consist of Jolt-aware AWT and Swing-based beans).

• Jolt Repository-A central Jolt Repository contains definitions of BEA Tuxedo services. These Repository definitions are used by Jolt at runtime to access Tuxedo services. You can export services to a Jolt client application or unexport services by hiding the definitions from the Jolt client. Using the Repository Editor, you can test new and existing BEA Tuxedo services independently of the client applications.

• Jolt Internet Relay-The Jolt Internet Relay is a component that routes messages from a Jolt client to a Jolt Server Listener (JSL) or Jolt Server Handler (JSH). This eliminates the need for the JSH and Tuxedo to run on the same machine as the Web server. The Jolt Internet Relay consists of the Jolt Relay (JRLY) and the Jolt Relay Adapter (JRAD).

Key Features

With BEA Jolt, you can leverage existing Tuxedo services and extend your transaction environment to the corporate intranet or world-wide Internet. The key feature of the Jolt architecture is its simplicity. Using Jolt, you can build, deploy and maintain robust, modular, and scalable electronic commerce systems that operate over the Internet.

BEA Jolt includes the following features:

• Java-based API for Simplified Development-With its Java-based API, BEA Jolt simplifies application design by providing well-designed object interfaces. Jolt supports the Java Developer's Kit (JDK) 1.2 and is fully compatible with Java threads. Jolt enables Java programmers to build graphical front-ends that use the Tuxedo application and transaction services without the need to understand detailed transactional semantics or without having to rewrite existing Tuxedo applications.

• Pure Java Client Development-Using Jolt, you can build a pure Java client that runs in any Java-enabled browser. Jolt automatically converts from Java to native BEA Tuxedo data types and buffers, and from Tuxedo back to Java. As a pure Java client, your applet or application does not need resident client-side libraries or installation; thus, you can download client applications from the network.

• Easy Access to Tuxedo Services via Jolt Repository-The BEA Jolt Repository facilitates Java application development by managing and presenting BEA Tuxedo service definitions that you can use in your Java client. A Jolt repository bulk loading utility lets you quickly integrate your existing Tuxedo services into the Jolt development environment. Jolt and Tuxedo simplify network and application scalability, while encouraging the reuse of application components.

• GUI-based Maintenance and Distribution of Tuxedo Services-The Jolt Repository Editor lets you manage BEA Tuxedo service definitions such as service names, inputs and outputs. The Jolt Repository Editor provides support for different input and output names for services defined in the Jolt Repository.

• Encryption for Secure Transaction Processing-BEA Jolt allows you to encrypt data transmitted between Jolt clients and the JSL/JSH. Jolt encryption addresses the issue of security that is essential for secure Internet transaction processing.

• Added Security via Internet Relay-BEA Jolt features an Internet Relay component that allows network administrators to separate their Web Server and Tuxedo application server. Web servers are generally considered insecure as they often exist outside a corporate firewall. The Jolt Internet Relay gives you greater flexibility to locate your BEA Tuxedo server in a secure location or environment on your network, yet still be able to handle transactions from Jolt clients on the Internet.

• Event Subscription Support-Jolt Event Subscription is used to receive event notifications from either Tuxedo services or other Tuxedo clients. Jolt Event Subscription lets you handle two types of Tuxedo application events:

  • Unsolicited Event Notifications. A Jolt client can receive these notifications when a Tuxedo client or service subscribes to unsolicited events and a Tuxedo client issues a broadcast or a directly targeted message.

  • Brokered Event Notifications. The Jolt client receives these notifications via the Tuxedo Event Broker. The Jolt client receives these notifications only when it subscribes to an event and any Tuxedo client or server posts an event.

How It Works

BEA Jolt connects Java clients to applications built using the BEA Tuxedo system. The Tuxedo system provides a set of modular services, each offering specific functionality related to the application as a whole. (Figure 1-1 illustrates the end-to-end view of the BEA Jolt architecture, as well as related Tuxedo components and their interactions.) For example, a simple banking application might have services such as INQUIRY, WITHDRAW, TRANSFER, and DEPOSIT. Typically, service requests are implemented in C or COBOL as a sequence of calls to a program library. Accessing a library from a native program means installing the library for the specific combination of CPU and operating system release on the client machine, a situation that Java was expressly designed to avoid. The Jolt Server implementation acts as a proxy for the Jolt client, invoking the Tuxedo service on behalf of the client. The BEA Jolt Server accepts requests from the Jolt clients and maps those requests into Tuxedo service requests.

Figure 1-1 BEA Jolt Architecture

Jolt Servers

The Jolt Server has several components that act in concert to pass Jolt client transaction processing requests to the Tuxedo application. The components are as follows:

• Jolt Server Listener (JSL). The JSL handles the initial Jolt client connection, and is responsible for assigning a Jolt client to the Jolt Server Handler.

• Jolt Server Handler (JSH). The JSH manages network connectivity, executes service requests on behalf of the client and translates Tuxedo buffer data into the Jolt buffer and vice versa.

• Jolt Repository Server (JREPSVR). The JREPSVR retrieves Jolt service definitions from the Jolt Repository and returns the service definitions to the JSH. The JREPSVR also updates or adds Jolt service definitions.

The following figure illustrates the Jolt Server and Jolt Repository components.

Figure 1-2 Jolt Server Components

Jolt Class Library

The BEA Jolt Class Library is a set of classes you can use in your Java application or applet to make service requests to the Tuxedo system from a Java enabled client. These Jolt classes allow you to access Tuxedo transaction services using objects.

When developing a Jolt client application, you only need to know about the classes that Jolt provides and the Tuxedo services that are exported by the Jolt Repository. Jolt hides the underlying application details. Using Jolt and Jolt's Class Library, you do not need to understand: the underlying transactional semantics, the language in which the services were coded, buffer manipulation, the location of services, or the names of databases used.

The Jolt API is a Java class library and has the benefits that Java provides: applets are downloaded dynamically and are only resident during runtime. As a result, there is no need for client installation, administration, management, or version control. If services are changed, the client application becomes aware of the changes at the next call to the Jolt Repository.

The following figure shows the flow of activity from a Jolt client to and from the Tuxedo system. The call-out numbers correspond to descriptions of the activity in the table that follows.

Figure 1-3 Using the Jolt Class Library to access Tuxedo services

The following table briefly describes the flow of activity involved in using the Jolt Class Library to access Tuxedo services.

Table 1-1 Using the Jolt Class Library

Process	Step	Action
Connection	1	A Java enabled Web browser downloads an HTML page using the HTTP protocol.
...	2	A Jolt applet is downloaded and executed in the Java Virtual Machine on the client.
...	3	The first Java applet task is to open a separate connection to the Jolt Server.
Request	4	The Jolt client now knows the signature of the service (such as, name, parameters, types) and can build a service request object based on Jolt class definitions, and make a method call.
...	5	The request is sent to the Jolt Server, which translates the Java based request into a Tuxedo request and forwards the request to the Tuxedo environment.
Reply	6	The Tuxedo system processes the request and returns the information to the Jolt Server, which translates it back to the Java applet.

JoltBeans

BEA Jolt now includes JoltBeans, Java beans components that you can use in a Java-enabled integrated development environment (IDE) to construct BEA Jolt clients. Using JoltBeans, you can create Jolt client applications with the ease of using typical JavaBeans. You can use popular JavaBeans-enabled development tools like Symantec Visual Café to graphically construct client applications.

BEA JoltBeans provide a JavaBeans-compliant interface to BEA Jolt. A fully functional BEA Jolt client can be developed without writing any code. You can drag and drop JoltBeans from the component palette of a development tool and position them on the Java form (or forms) of the Jolt client application you are creating. You can populate the properties of the beans and graphically establish event source-listener relationships between various beans of the application or applet. Typically, the development tool is used to generate the event hook-up code, or you can code the hook-up manually. Client development using JoltBeans is integrated with the BEA Jolt repository, providing easy access to available BEA Tuxedo functions.

ASP Connectivity for Tuxedo

The Jolt ASP Connectivity for Tuxedo Toolkit is an extension to the Jol Java class library. The Toolkit allows the Jolt client class library to be used in a Web server, such as the Microsoft Internet Information Server (IIS), to provide an interface between HTML clients or browsers, and Tuxedo services.

The Jolt ASP Connectivity for Tuxedo provides an easy-to-use interface for processing and generating dynamic HTML pages. You do not need to learn how to write Common Gateway Interface (CGI) transactional programs to access Tuxedo services.

Jolt Server and Jolt Client Communication

The Jolt system handles all communication between the Jolt Server and the Jolt client using the BEA Jolt Protocol. The communication process between the Jolt Server and the Jolt client applet or applications functions as follows:

1. Tuxedo service requests and associated parameters are packaged into a message buffer and delivered over the network to the Jolt Server.

2. The Jolt Server unpacks the data from the message, and performs any data conversions necessary, such as numeric format conversions or character set conversions.

3. The Jolt Server makes the appropriate service request to the application service requested by the Jolt client.

4. Once a service request enters the BEA Tuxedo system, it is executed in exactly the same manner as requests issued by any other Tuxedo client.

5. The results are then returned to the BEA Jolt Server, which packages the results and any error information into a message that is sent to the Jolt client.

6. The Jolt client then maps the contents of the message into the various Jolt client interface objects, completing the request.

Jolt Repository

The Jolt Repository is a database where Tuxedo services are defined, such as name, number, type, parameter size, and permissions. The Repository functions as a central database of definitions for Tuxedo services and permits new and existing Tuxedo services to be made available to Jolt client applications. A Tuxedo application can have many services or service definitions such as ADD_CUSTOMER, GET_ACCOUNTBALANCE, CHANGE_LOCATION, and GET_STATUS. All or only a few of these definitions may be exported to the Jolt Repository. Within the Jolt Repository, the developer or system administrator can export these services to the Jolt client application.

All Repository services that are exported to one client are exported to all clients. Tuxedo handles the cases where subsets of services may be needed for one client and not others. Figure 1-4 illustrates how the Jolt Repository brokers Tuxedo services to multiple Jolt client applications. The diagram shows four Tuxedo services, however the WITHDRAW service is not defined in the Repository and the TRANSFER service is defined but not exported.

Figure 1-4 Distributing Tuxedo Services via Jolt

Jolt Repository Editor

The Jolt Repository Editor is a Java-based GUI administration tool that gives the application administrator access to individual BEA Tuxedo services. With the Jolt Repository Editor you can define, test, and export services to Jolt clients.

Note: The Jolt Repository Editor only controls services for Jolt client applications. It cannot be used to make changes to the Tuxedo application.

The Jolt Repository Editor lets you extend and distribute Tuxedo services to Jolt clients without having to modify many lines of code. With the Jolt Repository Editor, you can modify parameters for Tuxedo services, logically group Tuxedo services into packages, and remove services from created packages. You can also make the services available to browser-based Jolt applets or Jolt applications by exporting the services.

Jolt Internet Relay

The Jolt Internet Relay is a component that routes messages from a Jolt client to the Jolt Server. The Jolt Internet Relay consists of the Jolt Relay (JRLY) and the Jolt Relay Adapter (JRAD). JRLY is a stand-alone software component that routes Jolt messages to the Jolt Relay Adapter. Requiring only minimal configuration to allow it to work with Jolt clients, the Jolt Relay eliminates the need for the Tuxedo system to run on the same machine as the Web server.

How to Jolt your Tuxedo Applications

The JRAD is a Tuxedo system server, but does not include any Tuxedo services. It requires command-line arguments to allow it to work with the JSH and the Tuxedo system. JRAD receives client requests from JRLY, and forwards the request to the appropriate JSH. Replies from the JSH are forwarded back to the JRAD, which sends the response back to the JRLY. A single Jolt Internet Relay (JRLY/JRAD pair) handles multiple clients concurrently.

The following steps show just how quickly and easily Jolt clients can be created and deployed.

1. Begin the process with a Tuxedo system application.

   For information about installing Tuxedo and creating a Tuxedo application, refer to the Tuxedo documentation set.

2. Install the Jolt system.

   Refer to Installing the BEA Tuxedo System.

3. Configure and define services using the Jolt Repository Editor or the Bulk Loader.

   For information regarding configuring the Jolt Repository Editor and making Tuxedo services available to Jolt, refer to: Appendix B, "System Messages"

4. Create a client application using the Jolt Class Library.

   The following documentation shows you how to program your client application using the Jolt Class Library:

   • "Using the Jolt Class Library"

   • API Reference in Javadoc

5. Run the Jolt-based client applet or application.

   Figure 1-5 Creating a Jolt Application