You can define the following types of static rules for a Mediator:

• Filter Expression

  You can define a filter expression that is applied to the message content (payload or headers). When you define a filter, the contents are analyzed before any service is invoked. For example, you might apply a filter expression that specifies that a service be invoked only if the message includes a customer ID, or if the value for that customer ID matches a certain pattern. For information about specifying filter expressions, see How to Specify an Expression for Filtering Messages.

• Transformations

  Mediator can transform message data before forwarding the message to a service. You can define transformations to set a value on the target payload by mapping data or by assigning values.

  The XSLT Mapper lets you define transformations that apply to the whole message body to convert messages from one XML schema to another. The Assign Values function works on individual fields. Using this dialog, you can assign values from the message (for example, payload and headers), from a constant, or from various system properties, such as the properties of an adapter present in the data path. For information about defining transformations, see How to Create XSLT Transformations and How to Assign Values.

• Accessing Header Variables from Expressions

  Mediator can detect any SOAP headers that are used in building the expression for the current routing rule operation. For information about accessing headers, see How to Access Headers for Filters and Assignments and Manual Expression Building for Accessing Properties for Filters and Assignments.

• Schematron-Based Validations

  You can specify the Schematron files that Mediator should use to validate different parts of an inbound message. For information about performing Schematron-based validations, see How to Use Semantic Validation.

• Java Callouts

  Mediator lets you add Java callouts to the routing rules. Java callouts enable you to use external Java classes to manipulate messages flowing through the Mediator. For information about using Java callouts, see How to Use Java Callouts.

• User-defined Extension Functions

  These are your own set of functions that can be used by the XSLT Mapper. For information about using user-defined extension functions, see "To add user-defined extension functions:".