This topic applies only to the IBM Business Automation Workflow Advanced configuration.

SCA to Java bridge

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You cannot directly wire a component with a Web Services Definition Language (WSDL) type of reference to another component that has a Java™ interface, but there is a utility that helps you create a bridge component to make a WSDL to Java connection. The component is generated, so you do not have to write conversion code.

Data that flows through IBM® Business Automation Workflow is modeled as XML schemas and processed by the server as service data objects or business objects. A service data object is a runtime representation of business data that implements the data object interface, as described in the Service Data Objects Version 2 specification.

Types that are modeled as XML and whose runtime representations are data objects are referred to as WSDL types, where inputs , outputs, and faults are described as XML schemas. Existing Java and Java 2 Platform Enterprise Edition applications process data as Java types. Java types include Java primitives, classes defined by the J2SE API, and user-defined Java classes.

In an integration environment, components that are processing WSDL types sometimes need to invoke existing Java applications that expect data as Java types. An example is a Service Component Architecture (SCA) component that needs to invoke a session EJB. This invocation requires a conversion between WSDL types and Java types. The conversion is accomplished by an SCA to Java bridge component.

You can generate the bridge component for the following Java elements:
  • a Java interface
  • a Java class that implements one, and only one, interface
  • a stateless session bean remote interface
The system generates an SCA Java component, which has the target Java interface as its reference and an interface that matches the WSDL port type that was just generated. This component takes WSDL types as parameters, converts them to Java types, and delegates the call to the target Java interface. Any returns or exceptions are converted to WSDL types and returned to the caller. The utility generates code from the imported Java interface or class, and the generated files take part of their name from that interface. The utility generates the following files:
  • java_classMapper.component
  • java_classMapper.wsdl
  • java_classMapper.java

You can generate the files and wiring in the IBM Integration Designer assembly editor (see Calling Java interfaces from WSDL references, which you can access from the related links below) or you can generate the files from IBM Workflow Server using the genMapper command. If you generate the files from the genMapper command, import those files into a module in IBM Integration Designer. You can then use the assembly editor to wire the WSDL reference and the Java interface to the generated component.

There are restrictions on the Java class or interface that you can drag onto the assembly editor canvas to generate a bridge component:
  • You can use a plain Java or stateless session bean remote interface.
  • The Java class can implement one, and only one, interface. If the class does not implement one interface or implements more than one interface, the assembly editor will not offer you the option to generate the bridge component.
  • If your input is a user-defined Java class, it must adhere to section 5.4 of the JAX-RPC 1.1 conventions. The JAX-RPC specification has implications for the generated code. For details of the specific type conversions, see Java to XML conversion in the related links below.

An interface consists of one or more operations, which in turn have parameters. When using an SCA-to-Java bridge component, you can pass these parameters only by value. The system uses the Java class name as the type name for the generated data object. When you need to pass parameters from the operations of a target Java interface that is a user-defined interface, you must override the code and provide a concrete class that the system can instantiate. If the runtime environment cannot find the type to create the concrete class, the system generates a runtime exception.

For some java.util container classes, the mapper generates complex types that are based on xsd:anyType as the WSDL type. These container classes include arrays, SortedMap, AbstractMap, BitSet, Dictionary, IdentityHashMap, LinkedHashMap, and TreeMap (see Java to XML conversion for more details). In some cases, you might need to override the generated code by writing custom conversion code.

Edit the generated code according to the commented instructions in the file, but do not change the file names. For links to topics that provide more details about editing that code, see the related tasks below.

Note: If the Java interface changes after you have completed the mapping, you can update the mapper implementation by running Regenerate Implementation for the mapping component. This matches the WSDL interface to that of the updated Java interface, as well as updating the mapping code in the mapper's Java implementation.