EE Concurrency Utilities

Context Services

The Context Service is a concurrency utility which creates contextual proxies from existent objects. WildFly Context Services are also used to propagate the context from a Java EE application invocation thread, to the threads internally used by the other EE Concurrency Utilities. Context Service instances may be created using the subsystem XML configuration:

  <context-services>
    <context-service
	name="default"
	jndi-name="java:jboss/ee/concurrency/context/default"
	use-transaction-setup-provider="true" />
  </context-services>

The name attribute is mandatory, and it's value should be a unique name within all Context Services.

The jndi-name attribute is also mandatory, and defines where in the JNDI the Context Service should be placed.

The optional use-trasaction-setup-provider attribute indicates if the contextual proxies built by the Context Service should suspend transactions in context, when invoking the proxy objects, and its value defaults to true.

Management clients, such as the WildFly CLI, may also be used to configure Context Service instances. An example to add and remove one named other:

/subsystem=ee/context-service=other:add(jndi-name=java\:jboss\/ee\/concurrency\/other)
/subsystem=ee/context-service=other:remove

Managed Thread Factories

The Managed Thread Factory allows Java EE applications to create new threads. WildFly Managed Thread Factory instances may also, optionally, use a Context Service instance to propagate the Java EE application thread’s context to the new threads. Instance creation is done through the EE subsystem, by editing the subsystem XML configuration:

  <managed-thread-factories>
    <managed-thread-factory
	name="default"
	jndi-name="java:jboss/ee/concurrency/factory/default"
	context-service="default"
	priority="1" />
  </managed-thread-factories>

The name attribute is mandatory, and it's value should be a unique name within all Managed Thread Factories.

The jndi-name attribute is also mandatory, and defines where in the JNDI the Managed Thread Factory should be placed.

The optional context-service references an existent Context Service by its name. If specified then thread created by the factory will propagate the invocation context, present when creating the thread.

The optional priority indicates the priority for new threads created by the factory, and defaults to 5.

Management clients, such as the WildFly CLI, may also be used to configure Managed Thread Factory instances. An example to add and remove one named other:

/subsystem=ee/managed-thread-factory=other:add(jndi-name=java\:jboss\/ee\/factory\/other)
/subsystem=ee/managed-thread-factory=other:remove

Managed Executor Services

The Managed Executor Service is the Java EE adaptation of Java SE Executor Service, providing to Java EE applications the functionality of asynchronous task execution. WildFly is responsible to manage the lifecycle of Managed Executor Service instances, which are specified through the EE subsystem XML configuration:

  <managed-executor-services>
    <managed-executor-service
	name="default"
	jndi-name="java:jboss/ee/concurrency/executor/default"
	context-service="default"
	thread-factory="default"
	hung-task-threshold="60000"
	core-threads="5"
	max-threads="25"
	keepalive-time="5000"
	queue-length="1000000"
	reject-policy="RETRY_ABORT" />
  </managed-executor-services>

The name attribute is mandatory, and it's value should be a unique name within all Managed Executor Services.

The jndi-name attribute is also mandatory, and defines where in the JNDI the Managed Executor Service should be placed.

The optional context-service references an existent Context Service by its name. If specified then the referenced Context Service will capture the invocation context present when submitting a task to the executor, which will then be used when executing the task.

The optional thread-factory references an existent Managed Thread Factory by its name, to handle the creation of internal threads. If not specified then a Managed Thread Factory with default configuration will be created and used internally.

The mandatory core-threads provides the number of threads to keep in the executor's pool, even if they are idle. A value of 0 means there is no limit.

The optional queue-length indicates the number of tasks that can be stored in the input queue. The default value is 0, which means the queue capacity is unlimited.

The executor’s task queue is based on the values of the attributes core-threads and queue-length:

If queue-length is 0, or queue-length is Integer.MAX_VALUE (2147483647) and core-threads is 0, direct handoff queuing strategy will be used and a synchronous queue will be created.
If queue-length is Integer.MAX_VALUE but core-threads is not 0, an unbounded queue will be used.
For any other valid value for queue-length, a bounded queue wil be created.

The optional hung-task-threshold defines a threshold value, in milliseconds, to hung a possibly blocked task. A value of 0 will never hung a task, and is the default.

The optional long-running-tasks is a hint to optimize the execution of long running tasks, and defaults to false.

The optional max-threads defines the the maximum number of threads used by the executor, which defaults to Integer.MAX_VALUE (2147483647).

The optional keepalive-time defines the time, in milliseconds, that an internal thread may be idle. The attribute default value is 60000.

The optional reject-policy defines the policy to use when a task is rejected by the executor. The attribute value may be the default ABORT, which means an exception should be thrown, or RETRY_ABORT, which means the executor will try to submit it once more, before throwing an exception.

Management clients, such as the WildFly CLI, may also be used to configure Managed Executor Service instances. An example to add and remove one named other:

/subsystem=ee/managed-executor-service=other:add(jndi-name=java\:jboss\/ee\/executor\/other, core-threads=2)
/subsystem=ee/managed-executor-service=other:remove

Managed Scheduled Executor Services

The Managed Scheduled Executor Service is the Java EE adaptation of Java SE Scheduled Executor Service, providing to Java EE applications the functionality of scheduling task execution. WildFly is responsible to manage the lifecycle of Managed Scheduled Executor Service instances, which are specified through the EE subsystem XML configuration:

  <managed-scheduled-executor-services>
    <managed-scheduled-executor-service
	name="default"
	jndi-name="java:jboss/ee/concurrency/scheduler/default"
	context-service="default"
	thread-factory="default"
	hung-task-threshold="60000"
	core-threads="5"
	keepalive-time="5000"
	reject-policy="RETRY_ABORT" />
  </managed-scheduled-executor-services>

The name attribute is mandatory, and it's value should be a unique name within all Managed Scheduled Executor Services.

The jndi-name attribute is also mandatory, and defines where in the JNDI the Managed Scheduled Executor Service should be placed.