Retrieving synchronous callout request messages from non-MDB applications

You must modify the Java™ application to retrieve the callout requests in the hold queue and to handle the correlation of the response to the appropriate request.

Prerequisite: Your WebSphere® Application Server administrator must configure a shareable connection factory to be used by the Java application to retrieve the callout requests.

The following steps are key steps in a Java application for retrieving and responding to a synchronous callout request from IMS.

Procedure

To retrieve the synchronous callout request:
1. Set the interaction commit mode to 0 (COMMIT_THEN_SEND).
```
interactionSpec.setCommitMode(IMSInteractionSpec.COMMIT_THEN_SEND); 
```
2. Set the interaction sync level to CONFIRM.
```
interactionSpec.setSyncLevel(IMSInteractionSpec.SYNC_LEVEL_CONFIRM); 
```
3. Specify the callout queue name to the OTMA tpipe (hold queue) name.
```
// An 8-character name of the OTMA asynchronous hold queue that the 
// messages are to be retrieved from
String calloutQueueName = new String (“CALLOUTQ”);
// Set the queue name for the callout messages
interactionSpec.setAltClientID(calloutQueueName);
```
4. Set the interaction verb to SYNC_RECEIVE_CALLOUT.
```
interactionSpec.setInteractionVerb(IMSInteractionSpec.SYNC_RECEIVE_CALLOUT);
```
5. Specify the type of callout request to retrieve: synchronous only (CALLOUT_REQUEST_SYNC), asynchronous only (CALLOUT_REQUEST_ASYNC), or both (CALLOUT_REQUEST_BOTH).
  The following example retrieves only synchronous callout request messages.
```
// Specify to retrieve only synchronous callout request messages
interactionSpec.setCalloutRequestType(IMSInteractionSpec.CALLOUT_REQUEST_SYNC); 
```
6. Specify the execution timeout value.
  The following example sets the timeout value to 5 seconds.
```
interactionSpec.setExecutionTimeout(5000);
```
7. Execute the interaction.
  The following example executes the interaction, and the request is returned as calloutRequestMsg.
```
iteraction.execute(interactionSpec, null, calloutRequestMsg); 
```
Obtain the correlation token from the IMSInteractionSpec instance.
The following example sets the timeout value to 5 seconds.
```
byte[] corrToken = interactionSpec.getSyncCalloutCorrelationToken();
```
Process the request.
In the previous example, the request is returned as calloutRequestMsg.
Send the response.
1. Set the interaction verb to SYNC_SEND.
```
interactionSpec.setInteractionVerb(IMSInteractionSpec.SYNC_SEND); 
```
2. Set the correlation token to be sent back with the request.
```
interactionSpec.setSyncCalloutCorrelationToken(corrToken); 
```
3. Execute the interaction.
  The following example executes the interaction and sends the callout response message (calloutRespondMsg).
```
iteraction.execute(interactionSpec, calloutRespondMsg, null); 
```