net.sf.okapi.common.observer

Class BaseObservable

java.lang.Object

net.sf.okapi.common.observer.BaseObservable

All Implemented Interfaces:

IObservable

Direct Known Subclasses:

WeakReferenceObservable

public class BaseObservable
extends Object
implements IObservable

Default implementation of an IObservable.

This implementation notifies the observers in a synchronous fashion. Note that this can cause trouble if you notify the observers while in a transactional context because once the notification is done it cannot be rolled back.

Author:

Richard Gomes, Srinivas Hasti

See Also:

Martin Fischer: Observer and Observable interfaces, Improved Observer/Observable, IObservable, IObserver, WeakReferenceObservable

Constructor Summary

Constructors

Constructor and Description
BaseObservable(IObservable observable)

Method Summary

Modifier and Type	Method and Description
void	addObserver(IObserver observer) Attaches a observer to the Observable.
int	countObservers() Counts how many Observers were attached to this class.
void	deleteObserver(IObserver observer) Detaches a previously attached observer to the observable.
void	deleteObservers() Detaches all previously attached observer to the observable.
List<IObserver>	getObservers() Returns list of observers registered with the Observable.
void	notifyObservers() Notifies all attached observers about changes in the observable.
void	notifyObservers(Object arg) Notifies all attached observers about changes in the observable.
protected void	wrappedNotify(IObserver observer, IObservable observable, Object arg) This method is intended to encapsulate the notification semantics, in order to let extended classes to implement their own version.

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseObservable

public BaseObservable(IObservable observable)

Method Detail

addObserver

public void addObserver(IObserver observer)

Description copied from interface: IObservable

Attaches a observer to the Observable. After attachment the observer gets informed about changes in the Observable.

Specified by:

addObserver in interface IObservable

Parameters:

observer - The observer to attach to the observable

countObservers

public int countObservers()

Description copied from interface: IObservable

Counts how many Observers were attached to this class.

Specified by:

countObservers in interface IObservable

Returns:

the number of Observers

See Also:

IObserver

getObservers

public List<IObserver> getObservers()

Description copied from interface: IObservable

Returns list of observers registered with the Observable. List returned is unmodifiable list.

Specified by:

getObservers in interface IObservable

Returns:

list of observers

deleteObserver

public void deleteObserver(IObserver observer)

Description copied from interface: IObservable

Detaches a previously attached observer to the observable. After detachment the observer does no longer receive change notifications from the observable.

Specified by:

deleteObserver in interface IObservable

Parameters:

observer - The observer to detach from the observable

deleteObservers

public void deleteObservers()

Description copied from interface: IObservable

Detaches all previously attached observer to the observable. After detachment observers do not longer receive change notifications from the observable.

Specified by:

deleteObservers in interface IObservable

notifyObservers

public void notifyObservers()

Description copied from interface: IObservable

Notifies all attached observers about changes in the observable.

Specified by:

notifyObservers in interface IObservable

notifyObservers

public void notifyObservers(Object arg)

Description copied from interface: IObservable

Notifies all attached observers about changes in the observable.

Specified by:

notifyObservers in interface IObservable

Parameters:

arg - an arbitrary Object to be passed to the Observer

wrappedNotify

protected void wrappedNotify(IObserver observer,
                             IObservable observable,
                             Object arg)

This method is intended to encapsulate the notification semantics, in order to let extended classes to implement their own version. Possible implementations are:

• remote notification;
• notification via SwingUtilities.invokeLater
• others...

The default notification simply does

 observer.update(observable, arg);
 

Parameters:

observer - the observer.

observable - the object to be observed.

arg - additional arguments.