public interface RemoteExecutor

A RemoteExecutor allows submitting and/or scheduling runnables and callables for execution within a Coherence cluster.

Using a RemoteExecutor

A RemoteExecutor may be obtained by a known name: RemoteExecutor.get(“executorName” Once a reference to a RemoteExecutor has been obtained, similar to an ExecutorService, tasks may be submitted:


 <pre>
     // obtain the named RemoteExecutor (defined in xml configuration; see below)
     RemoteExecutor executor = RemoteExecutor.get("MyExecutor");

     // submit a simple runnable to the cluster but only to the executors
     // named "MyExecutor"
     Future future = executor.submit(() -> System.out.println("EXECUTED));

     // block until completed
     future.get();
 </pre>

A RemoteExecutor allows scheduling of tasks independent of the underlying thread pool (more about that below); See:

schedule(Remote.Runnable, long, TimeUnit)
schedule(Remote.Callable, long, TimeUnit)
scheduleAtFixedRate(Remote.Runnable, long, long, TimeUnit)
scheduleWithFixedDelay(Remote.Runnable, long, long, TimeUnit)

In order to use an executor, it must first be configured within the application's cache configuration. To begin configuring executors, developers must include a reference to the coherence-concurrent module's NamespaceHandler:

Configuring RemoteExecutors


 <pre>
 &lt;cache-config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xmlns="http://xmlns.oracle.com/coherence/coherence-cache-config"
                xmlns:executor="class://com.oracle.coherence.concurrent.config.NamespaceHandler"
                xsi:schemaLocation="http://xmlns.oracle.com/coherence/coherence-cache-config coherence-cache-config.xsd
                                   class://com.oracle.coherence.concurrent.config.NamespaceHandler concurrent.xsd">
   ...
 &lt;cache-config>
 </pre>

In this case, the arbitrary namespace of c was chosen and will be used for the examples below.

The configuration supports multiple executor types and their related configuration. See the invalid input: '<'a href=https://github.com/oracle/coherence/blob/master/prj/coherence-concurrent/src/main/resources/concurrent.xsd">schema for configuration specifics.

It should be noted, that it will be normal to have the same executor configured on multiple Coherence cluster members. When dispatching a task, it will be sent to one of the executors matching the configured name for processing. Thus, if a member fails, the tasks will fail over to the remaining named executors still present in the cluster.

The lifecycle of registered executors is tied to that of the owning Coherence cluster member, thus if a cluster member is brought down gracefully, the remaining tasks running on the executor local to that member will continue to completion.

Example configurations


 <pre>
 &lt;!-- creates a single-threaded executor named <em>Single</em> -->
 &lt;c:single>
   &lt;c:name>Single&lt;/c:name>
 &lt;/c:single>
 </pre>


 <pre>
 &lt;!-- creates a fixed thread pool executor named <em>Fixed5</em> with five threads -->
 &lt;c:fixed>
   &lt;c:name>Fixed5&lt;/c:name>
   &lt;c:thread-count>5&lt;/c:thread-count>
 &lt;/c:fixed>
 </pre>


 <pre>
 &lt;!-- creates a cached thread pool executor named <em>Cached</em> -->
 &lt;c:cached>
   &lt;c:name>Cached&lt;/c:name>
 &lt;/c:cached>
 </pre>


 <pre>
 &lt;!-- creates a work-stealing thread pool executor named <em>Stealing</em> with a parallelism of five-->
 &lt;c:work-stealing>
   &lt;c:name>Stealing&lt;/c:name>
   &lt;c:parallelism>5&lt;/c:parallelism>
 &lt;/c:work-stealing>
 </pre>

An example defining a ThreadFactory.


 <pre>
 &lt;!-- creates a fixed thread pool executor named <em>Fixed5</em> with five threads and a custom thread factory -->
 &lt;c:fixed>
   &lt;c:name>Fixed5&lt;/c:name>
   &lt;c:thread-count>5&lt;/c:thread-count>
   &lt;c:thread-factory>
     &lt;instance>
       &lt;class-name>my.custom.ThreadFactory&lt;/class-name>
     &lt;/instance>
   &lt;/c:thread-factory>
 &lt;/c:fixed>
 </pre>

Since:: 21.12
Author:: rlubke 11.15.2021

Field Summary

Fields

Modifier and Type

Field

Description

static final String

DEFAULT_EXECUTOR_NAME

The name of the default executor; a single-threaded executor on each member running the coherence-concurrent module.
Method Summary

Modifier and Type

Method

Description

boolean

awaitTermination(long lcTimeout, TimeUnit unit)

Blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.

void

execute(Remote.Runnable command)

Executes the given command at some time in the future.

static RemoteExecutor

get(String sName)

Return the RemoteExecutor for the given name.

static RemoteExecutor

getDefault()

Return the default executor.

<T> List<Future<T>>

invokeAll(Collection<? extends Remote.Callable<T>> tasks)

Executes the given tasks, returning a list of Futures holding their status and results when all complete.

<T> List<Future<T>>

invokeAll(Collection<? extends Remote.Callable<T>> tasks, long lcTimeout, TimeUnit unit)

Executes the given tasks, returning a list of Futures holding their status and results when all complete or the timeout expires, whichever happens first.

<T> T

invokeAny(Collection<? extends Remote.Callable<T>> tasks)

Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do.

<T> T

invokeAny(Collection<? extends Remote.Callable<T>> tasks, long lcTimeout, TimeUnit unit)

Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do before the given timeout elapses.

boolean

isShutdown()

Returns true if this executor has been shut down.

boolean

isTerminated()

Returns true if all tasks have completed following shut down.

<V> ScheduledFuture<V>

schedule(Remote.Callable<V> callable, long lcDelay, TimeUnit unit)

Submits a value-returning one-shot task that becomes enabled after the given delay.

ScheduledFuture<?>

schedule(Remote.Runnable command, long lcDelay, TimeUnit unit)

Submits a one-shot task that becomes enabled after the given delay.

ScheduledFuture<?>

scheduleAtFixedRate(Remote.Runnable command, long lcInitialDelay, long lcPeriod, TimeUnit unit)

Submits a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is, executions will commence after initialDelay, then initialDelay + period, then initialDelay + 2 * period, and so on.

ScheduledFuture<?>

scheduleWithFixedDelay(Remote.Runnable command, long lcInitialDelay, long lcDelay, TimeUnit unit)

Submits a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next.

void

shutdown()

Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted.

List<Runnable>

shutdownNow()

Attempts to stop all actively executing tasks, halts the processing of waiting tasks, and returns a list of the tasks that were awaiting execution.

<T> Future<T>

submit(Remote.Callable<T> task)

Submits a value-returning task for execution and returns a Future representing the pending results of the task.

Future<?>

submit(Remote.Runnable task)

Submits a Runnable task for execution and returns a Future representing that task.

<T> Future<T>

submit(Remote.Runnable task, T result)

Submits a Runnable task for execution and returns a Future representing that task.

Field Details
- DEFAULT_EXECUTOR_NAME
  
  static final String DEFAULT_EXECUTOR_NAME
  
  The name of the default executor; a single-threaded executor on each member running the coherence-concurrent module.
  See Also:
  
  Constant Field Values
Method Details
- schedule
  
  ScheduledFuture<?> schedule(Remote.Runnable command, long lcDelay, TimeUnit unit)
  
  Submits a one-shot task that becomes enabled after the given delay.
  
  Parameters:
  
  command - the task to execute
  
  lcDelay - the time from now to delay execution
  
  unit - the time unit of the delay parameter
  
  Returns:
  
  a ScheduledFuture representing the pending completion of the task and whose get() method will return null upon completion
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if callable or unit is null
- schedule
  
  <V> ScheduledFuture<V> schedule(Remote.Callable<V> callable, long lcDelay, TimeUnit unit)
  
  Submits a value-returning one-shot task that becomes enabled after the given delay.
  
  Type Parameters:
  
  V - the type of the callable's result
  
  Parameters:
  
  callable - the function to execute
  
  lcDelay - the time from now to delay execution
  
  unit - the time unit of the delay parameter
  
  Returns:
  
  a ScheduledFuture that can be used to extract result or cancel
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if callable or unit is null
- scheduleAtFixedRate
  
  ScheduledFuture<?> scheduleAtFixedRate(Remote.Runnable command, long lcInitialDelay, long lcPeriod, TimeUnit unit)
  Submits a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is, executions will commence after initialDelay, then initialDelay + period, then initialDelay + 2 * period, and so on.
  The sequence of task executions continues indefinitely until one of the following exceptional completions occur:
  
  The task is explicitly cancelled via the returned future.
  
  The executor terminates, also resulting in task cancellation.
  
  An execution of the task throws an exception. In this case calling get on the returned future will throw ExecutionException, holding the exception as its cause.
  
  Subsequent executions are suppressed. Subsequent calls to isDone() on the returned future will return true.
  If any execution of this task takes longer than its period, then subsequent executions may start late, but will not concurrently execute.
  Parameters:
  
  command - the task to execute
  
  lcInitialDelay - the time to delay first execution
  
  lcPeriod - the period between successive executions
  
  unit - the time unit of the initialDelay and period parameters
  
  Returns:
  
  a ScheduledFuture representing pending completion of the series of repeated tasks. The future's get() method will never return normally, and will throw an exception upon task cancellation or abnormal termination of a task execution.
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if callable or unit is null
  
  IllegalArgumentException - if lcPeriod less than or equal to zero
- scheduleWithFixedDelay
  
  ScheduledFuture<?> scheduleWithFixedDelay(Remote.Runnable command, long lcInitialDelay, long lcDelay, TimeUnit unit)
  Submits a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next.
  The sequence of task executions continues indefinitely until one of the following exceptional completions occur:
  
  The task is explicitly cancelled via the returned future.
  
  The executor terminates, also resulting in task cancellation.
  
  An execution of the task throws an exception. In this case calling get on the returned future will throw ExecutionException, holding the exception as its cause.
  
  Subsequent executions are suppressed. Subsequent calls to isDone() on the returned future will return true.
  Parameters:
  
  command - the task to execute
  
  lcInitialDelay - the time to delay first execution
  
  lcDelay - the delay between the termination of one execution and the commencement of the next
  
  unit - the time unit of the initialDelay and delay parameters
  
  Returns:
  
  a ScheduledFuture representing pending completion of the series of repeated tasks. The future's get() method will never return normally, and will throw an exception upon task cancellation or abnormal termination of a task execution.
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if callable or unit is null
  
  IllegalArgumentException - if lcDelay less than or equal to zero
- invokeAll
  
  <T> List<Future<T>> invokeAll(Collection<? extends Remote.Callable<T>> tasks) throws InterruptedException
  
  Executes the given tasks, returning a list of Futures holding their status and results when all complete. Future.isDone() is true for each element of the returned list. Note that a completed task could have terminated either normally or by throwing an exception. The results of this method are undefined if the given collection is modified while this operation is in progress.
  
  Type Parameters:
  
  T - the type of the values returned from the tasks
  
  Parameters:
  
  tasks - the collection of tasks
  
  Returns:
  
  a list of Futures representing the tasks, in the same sequential order as produced by the iterator for the given task list, each of which has completed
  
  Throws:
  
  InterruptedException - if interrupted while waiting, in which case unfinished tasks are cancelled
  
  NullPointerException - if tasks or any of its elements are null
  
  RejectedExecutionException - if any task cannot be scheduled for execution
- invokeAll
  
  <T> List<Future<T>> invokeAll(Collection<? extends Remote.Callable<T>> tasks, long lcTimeout, TimeUnit unit) throws InterruptedException
  
  Executes the given tasks, returning a list of Futures holding their status and results when all complete or the timeout expires, whichever happens first. Future.isDone() is true for each element of the returned list. Upon return, tasks that have not completed are cancelled. Note that a completed task could have terminated either normally or by throwing an exception. The results of this method are undefined if the given collection is modified while this operation is in progress.
  
  Type Parameters:
  
  T - the type of the values returned from the tasks
  
  Parameters:
  
  tasks - the collection of tasks
  
  lcTimeout - the maximum time to wait
  
  unit - the time unit of the timeout argument
  
  Returns:
  
  a list of Futures representing the tasks, in the same sequential order as produced by the iterator for the given task list. If the operation did not time out, each task will have completed. If it did time out, some of these tasks will not have completed.
  
  Throws:
  
  InterruptedException - if interrupted while waiting, in which case unfinished tasks are cancelled
  
  NullPointerException - if tasks, any of its elements, or unit are null
  
  RejectedExecutionException - if any task cannot be scheduled for execution
- invokeAny
  
  <T> T invokeAny(Collection<? extends Remote.Callable<T>> tasks) throws InterruptedException, ExecutionException
  
  Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do. Upon normal or exceptional return, tasks that have not completed are cancelled. The results of this method are undefined if the given collection is modified while this operation is in progress.
  
  Type Parameters:
  
  T - the type of the values returned from the tasks
  
  Parameters:
  
  tasks - the collection of tasks
  
  Returns:
  
  the result returned by one of the tasks
  
  Throws:
  
  InterruptedException - if interrupted while waiting
  
  NullPointerException - if tasks or any element task subject to execution is null
  
  IllegalArgumentException - if tasks is empty
  
  ExecutionException - if no task successfully completes
  
  RejectedExecutionException - if tasks cannot be scheduled for execution
- invokeAny
  
  <T> T invokeAny(Collection<? extends Remote.Callable<T>> tasks, long lcTimeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
  
  Executes the given tasks, returning the result of one that has completed successfully (i.e., without throwing an exception), if any do before the given timeout elapses. Upon normal or exceptional return, tasks that have not completed are cancelled. The results of this method are undefined if the given collection is modified while this operation is in progress.
  
  Type Parameters:
  
  T - the type of the values returned from the tasks
  
  Parameters:
  
  tasks - the collection of tasks
  
  lcTimeout - the maximum time to wait
  
  unit - the time unit of the timeout argument
  
  Returns:
  
  the result returned by one of the tasks
  
  Throws:
  
  InterruptedException - if interrupted while waiting
  
  NullPointerException - if tasks, or unit, or any element task subject to execution is null
  
  TimeoutException - if the given timeout elapses before any task successfully completes
  
  ExecutionException - if no task successfully completes
  
  RejectedExecutionException - if tasks cannot be scheduled for execution
- submit
  
  <T> Future<T> submit(Remote.Callable<T> task)
  
  Submits a value-returning task for execution and returns a Future representing the pending results of the task. The Future's get method will return the task's result upon successful completion.
  If you would like to immediately block waiting for a task, you can use constructions of the form result = exec.submit(aCallable).get();
  Note: The Executors class includes a set of methods that can convert some other common closure-like objects, for example, PrivilegedAction to Callable form so they can be submitted.
  
  Type Parameters:
  
  T - the type of the task's result
  
  Parameters:
  
  task - the task to submit
  
  Returns:
  
  a Future representing pending completion of the task
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if the task is null
- submit
  
  <T> Future<T> submit(Remote.Runnable task, T result)
  
  Submits a Runnable task for execution and returns a Future representing that task. The Future's get method will return the given result upon successful completion.
  
  Type Parameters:
  
  T - the type of the result
  
  Parameters:
  
  task - the task to submit
  
  result - the result to return
  
  Returns:
  
  a Future representing pending completion of the task
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if the task is null
- submit
  
  Future<?> submit(Remote.Runnable task)
  
  Submits a Runnable task for execution and returns a Future representing that task. The Future's get method will return null upon successful completion.
  
  Parameters:
  
  task - the task to submit
  
  Returns:
  
  a Future representing pending completion of the task
  
  Throws:
  
  RejectedExecutionException - if the task cannot be scheduled for execution
  
  NullPointerException - if the task is null
- execute
  
  void execute(Remote.Runnable command)
  
  Executes the given command at some time in the future. The command may execute in a new thread, in a pooled thread, or in the calling thread, at the discretion of the Executor implementation.
  
  Parameters:
  
  command - the runnable task
  
  Throws:
  
  RejectedExecutionException - if this task cannot be accepted for execution
  
  NullPointerException - if command is null
- isShutdown
  
  boolean isShutdown()
  
  Returns true if this executor has been shut down.
  
  Returns:
  
  true if this executor has been shut down
- isTerminated
  
  boolean isTerminated()
  
  Returns true if all tasks have completed following shut down. Note that isTerminated is never true unless either shutdown or shutdownNow was called first.
  
  Returns:
  
  true if all tasks have completed following shut down
- awaitTermination
  
  boolean awaitTermination(long lcTimeout, TimeUnit unit) throws InterruptedException
  
  Blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.
  
  Parameters:
  
  lcTimeout - the maximum time to wait
  
  unit - the time unit of the timeout argument
  
  Returns:
  
  true if this executor terminated and false if the timeout elapsed before termination
  
  Throws:
  
  InterruptedException - if interrupted while waiting
- shutdown
  
  void shutdown()
  
  Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted. Invocation has no additional effect if already shut down.
  This method does not wait for previously submitted tasks to complete execution. Use awaitTermination to do that.
- shutdownNow
  
  List<Runnable> shutdownNow()
  
  Attempts to stop all actively executing tasks, halts the processing of waiting tasks, and returns a list of the tasks that were awaiting execution.
  This method does not wait for actively executing tasks to terminate. Use awaitTermination to do that.
  There are no guarantees beyond best-effort attempts to stop processing actively executing tasks. For example, typical implementations will cancel via Thread.interrupt(), so any task that fails to respond to interrupts may never terminate.
  
  Returns:
  
  list of tasks that never commenced execution
- get
  
  static RemoteExecutor get(String sName)
  
  Return the RemoteExecutor for the given name. Will return null if no RemoteExecutor is available by the given name.
  
  Parameters:
  
  sName - the RemoteExecutor name
  
  Returns:
  
  the RemoteExecutor for the given name.
  
  Throws:
  
  NullPointerException - if sName is null
  
  IllegalArgumentException - if sName is zero-length
- getDefault
  
  static RemoteExecutor getDefault()
  
  Return the default executor. This is a single-threaded executor service that is registered at service start.
  
  Returns:
  
  the default executor; a single-threaded executor service that is registered at service start

Interface RemoteExecutor

Using a RemoteExecutor

Configuring RemoteExecutors

Example configurations

Field Summary

Method Summary

Field Details

DEFAULT_EXECUTOR_NAME

Method Details

schedule

schedule

scheduleAtFixedRate

scheduleWithFixedDelay

invokeAll

invokeAll

invokeAny

invokeAny

submit

submit

submit

execute

isShutdown

isTerminated

awaitTermination

shutdown

shutdownNow

get

getDefault