Constructing Web Services with the Globus Toolkit Version 4

Loan Payment Processing Example

We provide this example to show how using the Globus Toolkit can solve the integration challenges of heterogeneous systems within the enterprise. Some applications may be mainframe legacy applications and some may use modern technologies such as J2EE. Even when using up-to-date technologies, sharing information between different applications within the same enterprise can present a tremendous challenge. Figure 2 shows an example of an interaction between loan payment processing and the accounting departments within a mortgage organization. The accounting department uses the loan payment processing service to account for the loan.

Figure 2. Loan processing grid architecture (click for full-size image)

To create and deploy a grid service, we need to:

• Define the service's interface by creating a WSDL file.
• Implement the service in Java.
• Define the deployment parameters by creating a WSDD file.
• Compile all of the source code and generate a GAR file using Ant.
• Deploy the GAR file using tools from the GT4 distribution.

We use the top-down approach (Figure 3) to create the grid service. This approach starts by providing a WSDL file that contains the abstract definition of the service including the types, messages and portTypes. Starting with a document/literal WSDL and then generating the Java artifacts from that leads to the most interoperability.

Figure 3. Top-down approach

We use some of the tools that come with the GT4 toolkit to generate the binding and stubs. The next step with this approach is to provide the implementation of the interfaces.