Visualforce Development Cookbook - Second Edition

Action chaining

Action chaining allows multiple controller action methods to be executed in a series from a Visualforce page, each in a separate transaction. This technique is rarely used, but does solve the following problems:

• Working around governor limits; for example, repeatedly polling an external system to determine if processing triggered through a web service call has completed without breaching the limit for callouts per transaction. In this case, the same action would be chained to poll the external system and then update the Visualforce page to indicate to the user whether the action has been completed.
• Avoiding the MIXED_DML_OPERATION error when the controller must modify setup and nonsetup records; for example, changing a user and an ...