Package org.apache.sling.event.jobs.consumer

Interface JobConsumer

@ConsumerType public interface JobConsumer
A job consumer consumes a job.

If the job consumer needs more features like providing progress information or adding more information of the processing, JobExecutor should be implemented instead.

A job consumer registers itself with the PROPERTY_TOPICS service registration property. The value of this property defines which topics a consumer is able to process. Each string value of this property is either

  • a job topic, or
  • a topic category ending with "/*" which means all topics in this category, or
  • a topic category ending with "/**" which means all topics in this category and all sub categories. This matching is new since version 1.2.
A consumer registering for just "*" or "**" is not considered.

For example, the value org/apache/sling/jobs/* matches the topics org/apache/sling/jobs/a and org/apache/sling/jobs/b but neither org/apache/sling/jobs nor org/apache/sling/jobs/subcategory/a. A value of org/apache/sling/jobs/** matches the same topics but also all sub topics like org/apache/sling/jobs/subcategory/a or org/apache/sling/jobs/subcategory/a/c/d.

If there is more than one job consumer or executor registered for a job topic, the selection is as follows:

  • If there is a single consumer registering for the exact topic, this one is used.
  • If there is more than a single consumer registering for the exact topic, the one with the highest service ranking is used. If the ranking is equal, the one with the lowest service ID is used.
  • If there is a single consumer registered for the category, it is used.
  • If there is more than a single consumer registered for the category, the service with the highest service ranking is used. If the ranking is equal, the one with the lowest service ID is used.
  • The search continues with consumer registered for deep categories. The nearest one is tried next. If there are several, the one with the highest service ranking is used. If the ranking is equal, the one with the lowest service ID is used.

If the consumer decides to process the job asynchronously, the processing must finish within the current lifetime of the job consumer. If the consumer (or the instance of the consumer) dies, the job processing will mark this processing as failed and reschedule.

Since:
1.0

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static interface 
    JobConsumer.AsyncHandler
    If the consumer decides to process the job asynchronously, this handler interface can be used to notify finished processing.
    static enum 
    JobConsumer.JobResult
    The result of the job processing.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    PROPERTY_JOB_ASYNC_HANDLER
    Job property containing an asynchronous handler.
    static final String
    PROPERTY_TOPICS
    Service registration property defining the jobs this consumer is able to process.

  • Method Summary

    Modifier and Type
    Method
    Description
    JobConsumer.JobResult
    process(Job job)
    Execute the job.

  • Field Details

    • PROPERTY_JOB_ASYNC_HANDLER

      static final String PROPERTY_JOB_ASYNC_HANDLER
      Job property containing an asynchronous handler.
      See Also:

    • PROPERTY_TOPICS

      static final String PROPERTY_TOPICS
      Service registration property defining the jobs this consumer is able to process. The value is either a string or an array of strings.
      See Also:

  • Method Details