The purpose of the acquireExistingTransformationConnection method is twofold:
  • Allow a middle-in-chain Integration Object access to the transformation connection from a servlet context
  • Check out the application from the client container to block subsequent requests from the browser while the initial request is still being processed.
This means that if a user attempts to access the transformation connection after it has been acquired and before it has been released, the browser displays an "application is busy" message page, which states that a possible cause is reloading the Web page before the application is ready. The caller uses the returned label to call the setHPubStartChainName() method of the Integration Object. The Integration Object uses this label to locate the connection against which to run. If a null label was returned, then the connection is not accessible to the Integration Object. If a HostConnectionException is thrown, the application instance exists, but there is no transformation connection. If an ApplicationUnavailableException is thrown, no application instance exists or, if it does, it is currently checked out. To prevent the Integration Object from destroying the transformation connection when an error is encountered, call the setHPubSaveConnOnError(true) method prior to invoking doHPTransaction() to run the Integration Object.