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Web services enable SAP calls to be made across the Internet or an intranet, using specialized versions of the XML language that allow a developer to specify the parameters, connections methods, and remote calls and store them for reference in a repository. At run time, a person, an interface, or another function, can read this repository and automatically invoke the service. Web services currently do not have industry standards for transactional behavior. Web services are useful when your function calls must be made across firewall boundaries. Using Web services, you can use functions provided by external providers, assuming you know the function interface.

Web Services Example:

A Web service exposes the "cup" interface, which provides a teacup. The Acme Company exposes the "tea" Web service, which provides a brown liquid when the correct parameter "money" is provided. A cup of tea can be received by invoking the "tea" Web service and passing the "money" parameter. Additional components are not required to receive tea using the "tea" Web service.

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Java Connector Architecture (JCA) provides a reusable component model to build and deploy multi-tier applications that are platform and vendor independent. JCA acts as a type of envelope or "container" that enables the adapter to run inside the application server and connect to SAP and immediately return the results. JCA is useful when your SAP system resides within a local intranet or is accessed directly. JCA implements JAVA Connection and Transaction models. JCA requires a resource adapter to be physically deployed on the host application server to access the remote EIS system.

For more information on event capabilities of the JCA connectors, see Configuring the Event Adapter for SAP. For more information on installing and deploying both connectors, see the iWay Installation and Configuration Guide.

Using combinations of JCA and Web services is possible. For example, a JCA application can be invoked by a Web service or a Web service may be implemented inside a JCA container. The standards and protocols are still evolving.

JCA Example

An application server, "Table" implements the "tea" container, which contains "tea, gas heat, water, and cup". A JCA container can be deployed that contains tea in the "Table" application server. If any of the elements of the "tea" container are missing, for example, "gas heat," then no tea is produced. The container must physically possess the "tea, gas heat, water, and cup" components to receive the tea.