MarkLogic Server allows you to set-up an alerting application to notify users when new content is available that matches a predefined query. This can be achieved through the Alerting API with the Content Processing Framework (CPF). CPF is designed to keep state for documents, so it is easy to use CPF to keep track of when a document in a particular scope is created or updated, and then perform some action on that document. However, although alerting works for document updates and inserting, it does not occur for document deletes. You will have to create a custom CPF pipeline to catch the delete through an appropriate status transition.
To achieve alerting for document delete, you will have to write your own custom pipeline with status transition to handle deletes. For example:
<annotation>custom delete action</ annotation>
The higher 'priority' value and 'always' = true indicates that the custom pipeline has precedence over the default status change handling pipeline to handle document deletes. Similarly, in the action module, you can write your custom code for alerting.
Note: By default, when a document is deleted, the on-delete pre-commit trigger is fired and it calls the action in the Status Change Handling pipeline (if enabled) for ‘delete’ status transition. It is recommended that you do not modify this pipeline as it can cause compatibility problems in future upgrades and releases of MarkLogic server.