com.neeve.emx
Class EmxActionExecutor<E,V>

java.lang.Object
  com.neeve.root.RootObject
      com.neeve.emx.EmxObject
          com.neeve.emx.EmxActionExecutor<E,V>

public final class EmxActionExecutor<E,V>
extends EmxObject

Executes actions in a dispatcher owner thread.

There are many cases when a user needs an action to be performed by the owner thread of the dispatcher where the current thread may or may not be the owner thread. To handle this case, the calling thread first compares itself against the dispatcher owner thread. If it is the same, it executes the action immediately. Otherwise, it posts a user event to the dispatcher and the action is performed from the user event handler. In case the action needs to be performed synchronously i.e. the calling thread cannot return until the action is complete, then the calling thread needs to block and wait until the dispatcher owner thread completes the action. This class abstracts this process.

Threading:

This class is safe for concurrent access by multiple threads.

Field Summary

static int

FLG_SYNC Indicates that the thread calling invoke(com.neeve.emx.IEmxDispatcher, com.neeve.emx.IEmxAction, E, int) should not wait for the action to complete before returning.

Constructor Summary

EmxActionExecutor()
Constructor

Method Summary

V	invoke(IEmxDispatcher dispatcher, IEmxAction<E,V> action, E object, int flags) Executes an action.

Methods inherited from class com.neeve.root.RootObject

getChecked, getThreaded, getTracer, setChecked, setTracer

Methods inherited from class java.lang.Object

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

Field Detail

FLG_SYNC

public static final int FLG_SYNC

Indicates that the thread calling invoke(com.neeve.emx.IEmxDispatcher, com.neeve.emx.IEmxAction, E, int) should not wait for the action to complete before returning. In this case, the thread will return immediately from the invoke method. The action execution status will be discarded in case this flag is specified.

See Also:

Constant Field Values

Constructor Detail

EmxActionExecutor

public EmxActionExecutor()

Constructor

Method Detail

invoke

public final V invoke(IEmxDispatcher dispatcher,
                      IEmxAction<E,V> action,
                      E object,
                      int flags)
               throws Exception

Executes an action.

Parameters:

dispatcher - The dispatcher in whose context the action needs to be executes.

action - the action to execute.

object - An opaque object that is passed to the action execute method.

flags - A set of flags used to qualify the operation of this method.

Throws:

Exception - Thrown if any exception occurs while invoking the action or by the action itself.

This method executes an action. It takes a dispatcher, an action, an opaque object and a set of flags as parameters. It first compares the calling thread against the dispatcher owner thread. If same, it either invokes the action immediately. If the calling thread is different from the dispatcher owner, it posts a user event to the dispatcher and either waits and immediately returns depending on the the flags specified. The dispatcher event handler invokes the action and returns any object or exception thrown by the action to the waiting thread (if any). The waiting thread returns the object or throws the exception returned by the action.

Threading:

This method is safe for concurrent access by multiple threads.