barsuift.simLife
Interface IObservable

public interface IObservable

Method Summary

void	addObserver(java.util.Observer o) Adds an observer to the set of observers for this object, provided that it is not the same as some observer already in the set.
int	countObservers() Returns the number of observers of this Observable object.
void	deleteObserver(java.util.Observer o) Deletes an observer from the set of observers of this object.
void	deleteObservers() Clears the observer list so that this object no longer has any observers.
boolean	hasChanged() Tests if this object has changed.
void	notifyObservers() If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.
void	notifyObservers(java.lang.Object arg) If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.

Method Detail

addObserver

void addObserver(java.util.Observer o)

Adds an observer to the set of observers for this object, provided that it is not the same as some observer already in the set. The order in which notifications will be delivered to multiple observers is not specified. See the class comment.

Parameters:

o - an observer to be added.

Throws:

java.lang.NullPointerException - if the parameter o is null.

deleteObserver

void deleteObserver(java.util.Observer o)

Deletes an observer from the set of observers of this object. Passing null to this method will have no effect.

Parameters:

o - the observer to be deleted.

notifyObservers

void notifyObservers()

If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.

Each observer has its update method called with two arguments: this observable object and null. In other words, this method is equivalent to:

notifyObservers(null)

See Also:

Observable.clearChanged(), Observable.hasChanged(), Observer.update(java.util.Observable, java.lang.Object)

notifyObservers

void notifyObservers(java.lang.Object arg)

If this object has changed, as indicated by the hasChanged method, then notify all of its observers and then call the clearChanged method to indicate that this object has no longer changed.

Each observer has its update method called with two arguments: this observable object and the arg argument.

Parameters:

arg - any object.

See Also:

Observable.clearChanged(), Observable.hasChanged(), Observer.update(java.util.Observable, java.lang.Object)

deleteObservers

void deleteObservers()

Clears the observer list so that this object no longer has any observers.

hasChanged

boolean hasChanged()

Tests if this object has changed.

Returns:

true if and only if the setChanged method has been called more recently than the clearChanged method on this object; false otherwise.

See Also:

Observable.clearChanged(), Observable.setChanged()

countObservers

int countObservers()

Returns the number of observers of this Observable object.

Returns:

the number of observers of this object.