ej.observable

Class SimpleObservable

java.lang.Object

ej.observable.SimpleObservable

Direct Known Subclasses:

KernelSimpleObservable

public class SimpleObservable
extends Object

This class represents an observable variant which can handle only a single observer.

Constructor Summary

Constructors

Constructor and Description
SimpleObservable() Creates a simple observable.

Method Summary

Modifier and Type	Method and Description
protected void	clearChanged() Indicates that this simple observable has no longer changed, or that it has already notified all of its observers of its most recent change, so that the hasChanged() method will now return false.
Observer	getObserver() Returns the observer of this simple observable, if it is set.
boolean	hasChanged() Gets whether or not this simple observable has changed.
void	notifyObserver() Notifies the registered observer, if any.
protected void	setChanged() Marks this simple observable as having been changed.
void	setObserver(Observer observer) Sets the observer of this simple observable.
void	unsetObserver() Unsets the observer of this simple observable.
void	unsetObserver(Observer observer) Unsets the observer of this simple observable if it the same instance as the given observer.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleObservable

public SimpleObservable()

Creates a simple observable.

Method Detail

clearChanged

protected void clearChanged()

Indicates that this simple observable has no longer changed, or that it has already notified all of its observers of its most recent change, so that the hasChanged() method will now return false. This method is called automatically by the notifyObserver() method.

getObserver

@Nullable
public Observer getObserver()

Returns the observer of this simple observable, if it is set.

Returns:

the observer of this simple observable, or null if it is not set.

hasChanged

public boolean hasChanged()

Gets whether or not this simple observable has changed.

Returns:

true if and only if the setChanged() method has been called more recently than the clearChanged() method on this simple observable, false otherwise.

notifyObserver

public void notifyObserver()

Notifies the registered observer, if any.

setChanged

protected void setChanged()

Marks this simple observable as having been changed. The hasChanged() method will now return true.

setObserver

public void setObserver(Observer observer)

Sets the observer of this simple observable.

Parameters:

observer - the observer to set.

Throws:

NullPointerException - if the given observer is null.

unsetObserver

public void unsetObserver()

Unsets the observer of this simple observable.

unsetObserver

public void unsetObserver(Observer observer)

Unsets the observer of this simple observable if it the same instance as the given observer.

Parameters:

observer - the observer to unset.