When one matching endpoint is returned

If you want to select a single service endpoint from the WebSphere® Service Registry and Repository (WSRR) using only the Endpoint Lookup mediation primitive, then set the Match Policy property to return one matching endpoint.

When a single endpoint is retrieved from the registry, the endpoint information is placed in both the Endpoint Lookup context and in the target address element in the message header. If the Use dynamic endpoint property of the callout node is checked, the message will be routed to the endpoint in the target address element, and therefore no further processing is required to select the endpoint.

Follow these steps to create an example mediation flow that uses an Endpoint Lookup primitive to retrieve a service endpoint from the WSRR and routes the message to the retrieved endpoint.

  1. Create a mediation flow component, and add a source interface and a target reference that contains the operation that you wish to invoke
  2. In order for the runtime to implement dynamic routing on a request, the callout node must be set to use the dynamic endpoint. Select the callout node, and click on the details page in the properties view. Ensure that the Use dynamic endpoint check box is selected.
  3. Optional: Promote the Use dynamic endpoint property so that the administrator can change it at runtime. Click the Promoted properties page, and select the promoted check box for the property.
  4. Drop an Endpoint Lookup primitive onto the mediation flow canvas, and select the properties that you want to use to query the WSRR registry. At runtime, a single endpoint that matches the query will be retrieved from the WSSR and placed in the target address element of the SMOHeader in the message (/headers/SMOHeader/Target/address), and the message will be routed to the URI specified in the address element, shown in the image below:
    SMO showing target address element in SMOHeader

    For valid URI formats for the supported target types, see Dynamic endpoint example URIs.

  5. The message containing the retrieved endpoint information will be propagated through the output terminal of the Endpoint Lookup primitive, and no further mediation is required to select the endpoint. You can directly wire the output terminal of the Endpoint Lookup to the callout node, or to another primitive to perform the next processing step of your flow.
  6. Optional: Promote the query properties of Endpoint Lookup, such as User properties, so that you can change the query to the registry at runtime without redeploying the mediation module.
  7. Optional: You can specify a default endpoint that the runtime uses if it cannot find a dynamic endpoint. For example:
    • Wire an import to a reference in the mediation flow editor, and wire the noMatch terminal to the corresponding node in the mediation flow editor.
    • Wire the noMatch terminal to another primitive (such as MessageSetter or Custom Mediation) which updates the /headers/smoHeaders/target/address element with the next location. Enable dynamic lookup on the callout node.
  8. Optional: If there are no endpoints matching the search criteria in the WSRR, the message is propagated to the noMatch terminal of the Endpoint Lookup primitive. You can wire the noMatch terminal to a mediation primitive for notification, such as an Event Emitter.
Example:

The following image shows an example mediation flow when match policy is return one matching endpoint.Example mediation flow with Endpoint Lookup primitive

Related tasks
When all matching endpoints are returned
Related reference
Runtime behavior of the Endpoint Lookup primitive
Dynamic endpoint example URIs
Message routing when dynamic endpoint property is set
Endpoint Lookup mediation primitive

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