org.refcodes.controlflow

Class ControlFlowUtility

java.lang.Object

org.refcodes.controlflow.ControlFlowUtility

public final class ControlFlowUtility
extends Object

Utility class addressing control flow related issues.

Method Summary

Modifier and Type	Method and Description
static ExecutorService	createDaemonExecutorService() Creates an ExecutorService which executes tasks as daemon threads; the Executors.newCachedThreadPool() is being used to do so.
static ExecutorService	createExecutorService() Returns a default ExecutorService retrieved from the Executors.
static void	joinFutures(Collection<? extends Future<?>> aFutures) Joins the Future instances contained in the given Collection.
static void	joinFutures(Future<?>... aFutures) Joins the Future instances contained in the given Collection.
static void	joinThreads(Collection<? extends Thread> aThreads) Joins the Thread instances contained in the given Collection.
static void	joinThreads(Thread... aThreads) Joins the Thread instances contained in the given Collection.
static void	shutdownGracefully(ExecutorService aExecutorService) Tries to orderly shutdown (ExecutorService.shutdown()) all tasks of an ExecutorService, after a timeout of ControlFlowConsts.NORM_DAEMON_LOOP_SLEEP_TIME_IN_MS milliseconds, shutdown is forced as of ExecutorService.shutdownNow(). ------------------------------------------------------------------------- CAUTION: Do only invoke this methods on ExecutorService instances you manage exclusively yourself, do not apply this method on ExecutorService instances provided to you by your application server (e.g. an JEE server)
static void	shutdownGracefully(ExecutorService aExecutorService, long aTimeOutInMs) Tries to orderly shutdown (ExecutorService.shutdown()) all tasks of an ExecutorService, after a given timeout in milliseconds, shutdown is forced as of ExecutorService.shutdownNow().
static void	throwIllegalStateException(boolean isIllegalState) Code redundancy preventing code snippet (in terms of aspect) throwing an IllegalStateException in case an illegal state false is being provided.
static ExecutorService	toManagedExecutorService(ExecutorService aExecutorService) Converts an ExecutorService to be a ManagedExecutorService with methods ExecutorService.shutdown() and ExecutorService.shutdownNow() being disabled as them are to be managed by an application server.
static Object	waitForFutures(Collection<? extends Future<?>> aFutures) Joins the Future instances contained in the given Collection.
static Object	waitForFutures(Future<?>... aFutures) Joins the Future instances contained in the given Collection.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

throwIllegalStateException

public static void throwIllegalStateException(boolean isIllegalState)
                                       throws IllegalStateException

Code redundancy preventing code snippet (in terms of aspect) throwing an IllegalStateException in case an illegal state false is being provided. This method can be called in the beginning of methods of instances which can be disposed (Disposable) or destroyed (as of org.refcodes.component.Destroyable or decomposed (as of org.refcodes.component.Decomposeable). In such cases the "disposed", "destroyed", "decomposed" or similar flag is being passed.

Parameters:

isIllegalState - When true, then an illegal state is being flagged which causes the according IllegalStateException with a default message being thrown.

Throws:

IllegalStateException - Thrown in case an instance is in a state not allowing the invocation of the according method; for calling that method the instance is in an illegal state.

joinThreads

public static void joinThreads(Collection<? extends Thread> aThreads)

Joins the Thread instances contained in the given Collection.

Parameters:

aThreads - The Collection containing the Thread instances to be joined.

joinThreads

public static void joinThreads(Thread... aThreads)

Joins the Thread instances contained in the given Collection.

Parameters:

aThreads - The Collection containing the Thread instances to be joined.

joinFutures

public static void joinFutures(Collection<? extends Future<?>> aFutures)

Joins the Future instances contained in the given Collection.

Parameters:

aFutures - The Collection containing the Future instances to be joined.

joinFutures

public static void joinFutures(Future<?>... aFutures)

Joins the Future instances contained in the given Collection.

Parameters:

aFutures - The Collection containing the Future instances to be joined.

waitForFutures

public static Object waitForFutures(Collection<? extends Future<?>> aFutures)
                             throws Exception

Joins the Future instances contained in the given Collection. Returns the first result detected or throws the first Exception which occurred.

Parameters:

aFutures - The Collection containing the Future instances to be joined.

Throws:

Exception

waitForFutures

public static Object waitForFutures(Future<?>... aFutures)
                             throws Exception

Joins the Future instances contained in the given Collection. Returns the first result detected or throws the first Exception which occurred.

Parameters:

aFutures - The Collection containing the Future instances to be joined.

Throws:

Exception

shutdownGracefully

public static void shutdownGracefully(ExecutorService aExecutorService)

Tries to orderly shutdown (ExecutorService.shutdown()) all tasks of an ExecutorService, after a timeout of ControlFlowConsts.NORM_DAEMON_LOOP_SLEEP_TIME_IN_MS milliseconds, shutdown is forced as of ExecutorService.shutdownNow(). ------------------------------------------------------------------------- CAUTION: Do only invoke this methods on ExecutorService instances you manage exclusively yourself, do not apply this method on ExecutorService instances provided to you by your application server (e.g. an JEE server). -------------------------------------------------------------------------

Parameters:

aExecutorService - The service which's threads are to be shut down soon.

shutdownGracefully

public static void shutdownGracefully(ExecutorService aExecutorService,
                                      long aTimeOutInMs)

Tries to orderly shutdown (ExecutorService.shutdown()) all tasks of an ExecutorService, after a given timeout in milliseconds, shutdown is forced as of ExecutorService.shutdownNow(). No shutdown is forced in case a timeout of o is being provided. ------------------------------------------------------------------------- CAUTION: Do only invoke this methods on ExecutorService instances you manage exclusively yourself, do not apply this method on ExecutorService instances provided to you by your application server (e.g. an JEE server). -------------------------------------------------------------------------

Parameters:

aExecutorService - The service which's threads are to be shut down after the given timeout.

aTimeOutInMs - The timeout after which to force shutdown eventually, in case 0 is being provided, then no shutdown is being forced (all threads are executed till them terminate normally).

toManagedExecutorService

public static ExecutorService toManagedExecutorService(ExecutorService aExecutorService)

Converts an ExecutorService to be a ManagedExecutorService with methods ExecutorService.shutdown() and ExecutorService.shutdownNow() being disabled as them are to be managed by an application server. Usually this method is being invoked with an ExecutorService originating from an application server. See ManagedExecutorService for more details.

Parameters:

aExecutorService - The ExecutorService to be transformed to a ManagedExecutorService.

Returns:

The ManagedExecutorService from the provided ExecutorService.

createExecutorService

public static ExecutorService createExecutorService()

Returns a default ExecutorService retrieved from the Executors.

Returns:

An ExecutorService to be used.

createDaemonExecutorService

public static ExecutorService createDaemonExecutorService()

Creates an ExecutorService which executes tasks as daemon threads; the Executors.newCachedThreadPool() is being used to do so.

Returns:

An ExecutorService running tasks as daemon threads.