Overview of Event Handling - EnterWorks_Process_Exchange_(EPX) - 10.6

EnterWorks EPX Programmers Reference

Product type
Product family
Precisely EnterWorks > EnterWorks Process Exchange (EPX)
Product name
Precisely EnterWorks
EnterWorks EPX Programmers Reference
Topic type
Programming Reference
First publish date

EPX uses an event notification scheme to inform clients of changes in the state of the various objects that exist in the system. The notification is based on the client’s specification of the type of events that the client is interested in. The process of defining the types of events that a client application is interested in is called event registration. An EPX client application may choose to initialize an event subscriber object using the com.enterworks.shared.event.SessionEventConsumer abstract class and register for specific events with the EPX server through this class. Events are generated as a result of transactions conducted in the EJB Container of the J2EE application server.

EPX events are composed of four parts: a subject, an aspect, a filter, and a value. An event subject is the category of the object, such as server or process activity, which the event pertains to. A generalized subject called generic transaction is most often useful to client applications that are interested in the majority of the events that are generated by the system. These generic transaction event notifications are delivered in bulk to a client application, when the state of several system objects within the boundary of a single server-side transaction.

The aspect of the event is the type of transaction, such as add, update, or delete, that was performed on the object related to an event. The ANY aspect is used to denote any transaction type.

The filter and value of the event is used to narrow interest from all objects of a particular class (the event subject) to a subset or event of just one object, thereby limiting the number of unnecessary events that a client receives. Some of the available filters for EPX are object identifier, user identifier, BIC identifier, and unique identifier (natural key). Wildcards are supported for the values of a filter using the percent (%) character, as are the use of the actual object identifier value.

During the event registration process a client application can specify one or more combinations of event subjects, aspects, filters and filter values.

For more information about filter types, please refer to the Javadoc documentation located in the docs\javadoc directory of the EPX installation.

Refer to the class com.enterworks.shared.event.EventRegistration for the definitions of several constants related to event subjects, aspects, and filters.