JMS Integration with Message Service (ApacheMQ)

Feature

• Users who operate a Message Service want to integrate their applications with JobScheduler. Patterns for Enterprise Application Integration (EAI) include:
  • Applications send job start requests to JobScheduler.
  • Applications receive processing results from jobs and job chains executed with JobScheduler.
• Such EAI scenarios provide the following advantages:
  • reduce complexity
    • at a the topological level, i.e. each application implements only one interface to the Message Servcice.
    • of error handling as a Message Service would be considered to be highly available.
  • manage messages centrally
• The JMS integration scenario includes a separate Java based consumer to be implemented in order to receive and parse messages and to translate messages received into job start requests. The reasons for this decision are:
  • JMS is certainly standardized, however, the content and format of messages requires individual parsing.
  • JobScheduler offers an XML command interface that can be used by any consumer to request job starts.

Szenario 1: Detached JobScheduler JMS Interface
1. Use Case

• An application prompts JobScheduler to start a job.

2. Producer

• Creates a text message in the XML format for the queue "JobChains". The content of the message can be e.g.:

  <add_order job_chain='REL_PATH/JOBCHAIN_NAME' at='now'></add_order>
  

• sends the message to the specific queue

3. Consumer

• Reads a message from the queue „JobChains" and sends the XML snippet via TCP/UDP to a JobScheduler instance

Szenario 2: Generic JobScheduler JMS Interface

1. Use Case

• A Java job runs in a job chain and implements the Producer to send information to the Message Service after completion of a number of job nodes in a job chain.
• A Java job runs in a job chain and implements the Consumer, i.e. connects to the Message Service to check for new messages that include possible job start requests.
• The Producer as well as the Consumer run in any job chain.

2. Producer

• Producer: Jobs sends some information to a message queue to signal completion of a job chain.

3. Consumer

• Consumer: Reads JobScheduler XML API command from a message and hands over the XML command to JobScheduler for execution.

Deliverables

• The implementation is independent from the JobScheduler release and consists of Java examples that are separately available with the below articles.
• A number of articles in the Product Knowledge Base describe the implementation for each scenario.