Package org.refcodes.eventbus

Enum DispatchStrategy

java.lang.Object

java.lang.Enum<DispatchStrategy>

org.refcodes.eventbus.DispatchStrategy

All Implemented Interfaces:

Serializable, Comparable<DispatchStrategy>

public enum DispatchStrategy
extends Enum<DispatchStrategy>

The DispatchStrategy defines how child events are published within a parent event publish cycle.

Enum Constant Summary

Enum Constants

Enum Constant	Description
ASYNC	Same as the SEQUENTIAL approach with the difference that the sequential dispatch process is done asynchronously, freeing your parent's thread immediately after publishing your parent event.
CASCADE	The parent (invoker) thread is used to publish the parent's event to all matching observers (and is blocked till done).
PARALLEL	Each matching observer is invoked in its own thread.
SEQUENTIAL	The parent (invoker) thread is used to publish the parent's event as well as the child events published by the matching observers of the parent event (and so on, in case them use SEQUENTIAL as well).

Method Summary

Modifier and Type	Method	Description
static DispatchStrategy	valueOf(String name)	Returns the enum constant of this type with the specified name.
static DispatchStrategy[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

SEQUENTIAL

public static final DispatchStrategy SEQUENTIAL

The parent (invoker) thread is used to publish the parent's event as well as the child events published by the matching observers of the parent event (and so on, in case them use SEQUENTIAL as well). Any observer (directly or indirectly) invoked by your invoking thread can block your invoking thread.

ASYNC

public static final DispatchStrategy ASYNC

Same as the SEQUENTIAL approach with the difference that the sequential dispatch process is done asynchronously, freeing your parent's thread immediately after publishing your parent event. Exactly one extra thread is created to kick off the asynchronous way of doing a sequential dispatch. Any observer (directly or indirectly) invoked by the "asynchronous" thread can block any other observer in that chain, but not your invoking thread.

CASCADE

public static final DispatchStrategy CASCADE

The parent (invoker) thread is used to publish the parent's event to all matching observers (and is blocked till done). Child events published by the matching observers invoked with the parent's event are queued until the parent's thread finished dispatching the parent's event. The queued child events then are published in their own separate threads, now considered being parent events with their according parent threads, to all matching observers (dispatching as described above). The CASCADE strategy is useful when publishing lifecycle or bootstrapping events to make sure, that any observer was notified before publishing post-lifecycle actions. Observers directly invoked by your invoking thread can block your invoking thread and indirectly invoked observers called by your directly invoked observers using the SEQUENTIAL strategy for publishing their events.

PARALLEL

public static final DispatchStrategy PARALLEL

Each matching observer is invoked in its own thread. No observer can block your invoking thread.

Method Detail

values

public static DispatchStrategy[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (DispatchStrategy c : DispatchStrategy.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static DispatchStrategy valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null