Subflow mediation primitive

Introduction

Use mediation subflows to reuse common patterns in mediation flows, and also as a way to group primitives in the Mediation Flow editor.

A mediation subflow can be created in a module, mediation module, or library. A mediation subflow must be used within a mediation flow. It is good practice to store subflows in libraries so that they can be easily shared between mediation flows in different modules.

A mediation subflow has one or more in nodes, one or more mediation primitives, and one more out nodes. The in and out nodes become the input and output terminals on the subflow mediation primitive.

Unlike mediation flows, the inputs and outputs of a subflow are not tied to specific interfaces. Instead, the in and out nodes represent the inputs and outputs of the subflow. In a wired mediation flow, these nodes have message types associated with them. The message types on these nodes are not defined when the subflow is created; they can be changed later.

Details

Promoting the property of a mediation primitive in a mediation flow allows an administrator to change the value of the property at run time. When you promote a property in a subflow, it becomes a property of the subflow mediation primitive. You can then set the value of the property in the mediation flow, or further promote the property in the parent mediation flow. You might want to set the value of the property in the mediation flow at development time. If you reuse the same subflow in multiple places in a flow, you might not want to use the same alias name for the property depending on the behavior you want to see.

For mediation primitives contained in a subflow, promoting a property results in the creation of a corresponding property on each subflow mediation primitive that refers to that subflow. The property can then be promoted again until eventually it reaches the top level request, response, or fault flow.

Any property that you promote from a primitive in the top level request, response, or fault flow is also a dynamic property. A dynamic property can be overridden, at run time, using a mediation policy. Although you can override promoted properties dynamically, you must always specify a valid default value.

Promoted properties have an alias name which, for a mediation primitive in the top level request, response, or fault flow, is the name displayed on the runtime administrative console. For a mediation primitive in a subflow, the alias name is the name by which the property is known in the parent flow. You can set the alias name and the alias value from WebSphere Integration Developer. Multiple promoted properties can be given the same alias name if they are of the same type. In one module or mediation module, promoted properties that have the same alias name and group use the same value. Generally, you should choose a suitable alias name for your promoted properties rather than accept the default name: choosing a suitable name helps you identify properties at run time.

Usage

You can reuse mediation logic for common tasks by creating mediation subflows. A mediation subflow can be invoked from multiple mediation flows, or multiple times within the same mediation flow. A mediation subflow is invoked from a parent mediation flow using a subflow mediation primitive.