org.jquantlib.util
Class DefaultObservable

java.lang.Object
  org.jquantlib.util.DefaultObservable

All Implemented Interfaces:

Observable

Direct Known Subclasses:

WeakReferenceObservable

@NotThreadSafe
public class DefaultObservable
extends java.lang.Object
implements Observable

Default implementation of an Observable.

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, Observable, Observer, WeakReferenceObservable

Field Summary

private static Logger	logger
private Observable	observable
private java.util.List<Observer>	observers

Constructor Summary

DefaultObservable(Observable observable)

Method Summary

void	addObserver(Observer observer) Attaches a observer to the Observable.
int	countObservers() Counts how many Observers were attached to this class.
void	deleteObserver(Observer observer) Detaches a previously attached observer to the observable.
void	deleteObservers() Detaches all previously attached observer to the observable.
java.util.List<Observer>	getObservers() Returns list of observers registered with the Observable.
void	notifyObservers() Notifies all attached observers about changes in the observable.
void	notifyObservers(java.lang.Object arg) Notifies all attached observers about changes in the observable.
protected void	wrappedNotify(Observer observer, Observable observable, java.lang.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

Field Detail

logger

private static final Logger logger

observers

private final java.util.List<Observer> observers

observable

private final Observable observable

Constructor Detail

DefaultObservable

public DefaultObservable(Observable observable)

Method Detail

addObserver

public void addObserver(Observer observer)

Description copied from interface: Observable

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

Specified by:

addObserver in interface Observable

Parameters:

observer - The observer to attach to the observable

countObservers

public int countObservers()

Description copied from interface: Observable

Counts how many Observers were attached to this class.

Specified by:

countObservers in interface Observable

Returns:

the number of Observers

See Also:

Observer

getObservers

public java.util.List<Observer> getObservers()

Description copied from interface: Observable

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

Specified by:

getObservers in interface Observable

Returns:

list of observers

deleteObserver

public void deleteObserver(Observer observer)

Description copied from interface: Observable

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 Observable

Parameters:

observer - The observer to detach from the observable

deleteObservers

public void deleteObservers()

Description copied from interface: Observable

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 Observable

notifyObservers

public void notifyObservers()

Description copied from interface: Observable

Notifies all attached observers about changes in the observable.

Specified by:

notifyObservers in interface Observable

notifyObservers

public void notifyObservers(java.lang.Object arg)

Description copied from interface: Observable

Notifies all attached observers about changes in the observable.

Specified by:

notifyObservers in interface Observable

Parameters:

arg - an arbitrary Object to be passed to the Observer

wrappedNotify

protected void wrappedNotify(Observer observer,
                             Observable observable,
                             java.lang.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 -

observable -

arg -