ExecutionSubscriber

SPI that allows the execution of individual interactions (action invocations or property edits) to be subscribed to.

The typical use case is to facilitate coarse-grained messaging for system-to-system interactions, that is from an Apache Causeway application to some other system. This could be done using a pub/sub bus such asApache ActiveMQwithApache Camel.

Only actions/properties annotated for publishing (using Action#executionPublishing() or Property#executionPublishing() are published.

API

ExecutionSubscriber.java

interface ExecutionSubscriber {
  void onExecution(Execution<?, ?> execution)     (1)
}

1	onExecution(Execution) Callback to notify that an interaction (an action invocation or property edit, as represented by Execution ) has completed.

Members

onExecution(Execution)

Callback to notify that an interaction (an action invocation or property edit, as represented by Execution ) has completed.

This callback method is called by the framework immediately after the interaction (not at the end of the transaction, unlike some of the other subscribers).

Most implementations are expected to use Execution#getDto() to create a serializable XML representation of the execution. The easiest way to do this is using InteractionDtoUtils#newInteractionDto(Execution) .

Implementation

This is an SPI, and the framework provides several implementations.

The framework allows multiple implementations of this service to be registered; all will be called.

Applib (Log4j2)

The applib provides a simple implementation, ExecutionLogger, that just logs events as they are received.

It can be configured using:

log4j2-spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
  <Properties> ... </Properties>
  <Appenders> ... </Appenders>
  <Loggers>
    ...
    <logger
      name="org.apache.causeway.applib.services.publishing.log.ExecutionLogger"
      level="debug"/>
    ...
  </Loggers>
</Configuration>

See the log4j2-spring.xml file in simpleapp for the omitted detail.

Execution Log

The Execution Log module also provides an implementation, ExecutionSubscriberForExecutionLog. This implementation persists an instance of the ExecutionLogEntry entity for each event.

Execution Outbox

The Execution Outbox module also provides an implementation, ExecutionSubscriberForExecutionOutbox. This implementation persists an instance of the ExecutionOutboxEntry entity for each event.

Wrapper Factory

If the WrapperFactory is used to call other objects then the metrics are captured for each sub-execution.