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 and 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 class	JobConsumer.JobResult The result of the job processing.

Field Summary

Fields

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

Method Summary

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

Field Detail

PROPERTY_JOB_ASYNC_HANDLER

static final java.lang.String PROPERTY_JOB_ASYNC_HANDLER

Job property containing an asynchronous handler.

See Also:

Constant Field Values

PROPERTY_TOPICS

static final java.lang.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:

Constant Field Values

Method Detail

process

JobConsumer.JobResult process(Job job)

Execute the job.

If the job has been processed successfully, JobConsumer.JobResult.OK should be returned. If the job has not been processed completely, but might be rescheduled JobConsumer.JobResult.FAILED should be returned. If the job processing failed and should not be rescheduled, JobConsumer.JobResult.CANCEL should be returned.

If the consumer decides to process the job asynchronously it should return JobConsumer.JobResult.ASYNC and notify the job manager by using the JobConsumer.AsyncHandler interface.

If the processing fails with throwing an exception/throwable, the process will not be rescheduled and treated like the method would have returned JobConsumer.JobResult.CANCEL.

Parameters:

job - The job

Returns:

The job result