Event Model in LEAD Project

1. Overview

Notification system plays an important role in the communications between various Web services involved in the LEAD project. WS-Messenger is applied in the LEAD project to create all the entities in the notification system, including the event consumers, the event sources and the notification broker. Figure 1 shows the service interactions using the notification system in the LEAD project.

Figure 1: Service Interaction with Event Service

Some services are event consumers. They need information about workflow execution status, output data location, etc. Specifically, the services include:

Some services are event sources. They publish notification messages on status updates, e.g. workflow execution status, output data location. Services that are event sources include:

The descriptions of each service is available at here.

2. Types of Event Messages

Event messages are published following three different schema files: workflow tracking schema, Calder notification schema and auditing notification schema.

A. Workflow tracking schema

Workflow tracking schema (XSD file) has 13 different type of messages.

A1. ServiceInitialized
A2. ServiceTerminated
A3. InvokingService
A4. ServiceInvoked
A5. InvokingService [Succeeded | Failed]
A6. DataTransfer
A7. Computation
A8. DataProduced
A9. DataConsumed
A10. SendingResponse
A11. ReceivedResponse
A12. SendingResponse[Succeeded | Failed]
A13. WorkflowInitialized
A14. workflowTerminated
A15. Unknown

The detailed message content is available here. List of all activities is available here. Sample messages following this schema is available here.

B. Calder Notification Schema

Calder notification schema (XSD file) has 7 different type of messages.

B1. queryStarted
B2. queryFailedToStart
B3. queryActive
B4. queryExpired
B5. queryPublishResult
B6. queryNoDetection
B7. triggerFound

C. Auditing Notification Schema

Auditing notification schema has1 type of message.

C1. ApplicationAuditType

The auditing schema and its description are available here.

3. Interactions among Publishers and Consumers

The interaction among publishes and consumer is explained in this document.


Contact: Yi Huang

Last updated: 8/8/2007