net.sf.eBus.config

Class EConfigure.Dispatcher

java.lang.Object

net.sf.eBus.config.EConfigure.Dispatcher

All Implemented Interfaces:

Comparable<EConfigure.Dispatcher>

Enclosing class:

EConfigure

public static final class EConfigure.Dispatcher
extends Object
implements Comparable<EConfigure.Dispatcher>

An application may create dispatch threads with a given unique name and the following parameters:

• Thread priority: minimum, maximum, or normal thread priority.
• Run Queue Type: specifies whether run queue threads use a blocking, spinning, spin+park, or spin+yield technique to poll clients from the run queue.
• Spin Limit: if run queue type is either spin+park or spin+yield, then this is the number of times the dispatcher thread will poll the run queue before parking or yielding.
• Park Time: if run queue type is spin+park, then this is the number of nanoseconds the dispatcher thread will park after the spin limit is reached. When park returns, the thread will go back to spinning on poll.
• Quantum: nanosecond run quantum assigned to each client for this dispatcher group. If a client exhausts this quantum upon completing a task, the client is placed back on the end of the FIFO run queue and its quantum is reset to this value. Note that eBus does not preempt the client. It checks for quantum exhaustion when the client task returns.
• Group thread count: number of dispatcher threads in this group.
• Default group flag: true if this is the default dispatcher group. If a client is not assigned to any particular group, then it is assigned to the default group. If this flag is true, then the Classes parameter is ignored. There may be only one default dispatcher group.
• Classes: a list of application classes. Clients which are instances of these classes are assigned to this dispatcher group. This parameter is valid only if this is not the default dispatcher group.

Special Dispatchers

There are two special, pre-defined eBus Dispatcher names: "swing" and "javafx" (case insensitive). These Dispatchers use the Swing/JavaFX GUI thread to deliver eBus messages to a client. This means that the client callback is free to update the GUI because the callback code is running on the GUI thread.

Only two properties are supported by special Dispatchers: EConfigure.DEFAULT_KEY and EConfigure.CLASSES_KEY. All other properties are ignored by special Dispatchers. The reason is that the underlying GUI threads are implemented and configured by the GUI package and cannot be altered by eBus.

It may be useful to define the GUI thread Dispatcher as the default Dispatcher and then create a separate eBus Dispatcher for non-GUI classes. This way, an application class updating the display will be assigned to the GUI thread without needing to add that class to the GUI Dispatcher classes property.

Method Summary

Modifier and Type	Method and Description
Class<?>[]	classes() Returns the classes assigned to this dispatcher.
int	compareTo(EConfigure.Dispatcher o)
EConfigure.DispatcherType	dispatchType() Returns the dispatch method type.
boolean	equals(Object o)
int	hashCode()
boolean	isDefault() Returns true if this user-defined dispatcher is the default dispatcher.
String	name() Returns the unique dispatcher name.
int	numberThreads() Returns the number of threads in this dispatcher.
long	parkTime() Returns the park time used by spin+park thread type.
int	priority() Returns the dispatcher thread priority.
long	quantum() Returns the client run-time quantum assigned by this dispatcher.
ThreadType	runQueueType() Returns the thread type which defines how the next client is acquired from the run queue.
long	spinLimit() Returns the spin limit used by spin+park and spin+yield thread types.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

compareTo

public int compareTo(EConfigure.Dispatcher o)

Specified by:

compareTo in interface Comparable<EConfigure.Dispatcher>

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

name

public String name()

Returns the unique dispatcher name.

Returns:

dispatcher thread name.

dispatchType

public EConfigure.DispatcherType dispatchType()

Returns the dispatch method type.

Returns:

dispatch method type.

runQueueType

public ThreadType runQueueType()

Returns the thread type which defines how the next client is acquired from the run queue.

Returns:

run queue-acquisition type.

spinLimit

public long spinLimit()

Returns the spin limit used by spin+park and spin+yield thread types.

Returns:

spin limit.

parkTime

public long parkTime()

Returns the park time used by spin+park thread type.

Returns:

nanosecond park time.

isDefault

public boolean isDefault()

Returns true if this user-defined dispatcher is the default dispatcher.

Returns:

true if the default dispatcher.

classes

public Class<?>[] classes()

Returns the classes assigned to this dispatcher. Returned array may be empty but will not be null.

Returns:

dispatcher class array.

priority

public int priority()

Returns the dispatcher thread priority.

Returns:

thread priority.

quantum

public long quantum()

Returns the client run-time quantum assigned by this dispatcher.

Returns:

client run-time quantum.

numberThreads

public int numberThreads()

Returns the number of threads in this dispatcher.

Returns:

dispatcher thread count.