Module io.github.astrapisixtynine.design.patterns.observer

Package io.github.astrapi69.design.pattern.observer.api

Interface Subject<T,O extends Observer<T>>

Type Parameters:

T - the generic type of the observable object whose state is being observed

O - the generic type of the observer that is observing the subject

All Known Implementing Classes:

AbstractSubject, ChatRoom

public interface Subject<T,O extends Observer<T>>

The interface Subject represents the "subject" in the Observer design pattern The subject is the object whose state changes are being observed by one or more observers When the state of the subject changes, the observers are notified of the change

Method Summary

Modifier and Type	Method	Description
default void	add(O observer)	Adds the given observer to the list of observers
default void	addAll(Collection<O> observers)	Adds the given observers to the list of observers
T	getObservable()	Gets the observable object, which is the object being observed for state changes
List<O>	getObservers()	Gets the list of observers that wish to be notified of changes to the observable object
default void	remove(O observer)	Removes the given observer from the list of observers
default void	removeAll(Collection<O> observers)	Removes the given observers from the list of observers
void	setObservable(T observable)	Sets the observable object, which is the object being observed for state changes
default void	updateObservers()	Notifies all observers of a change in the state of the observable object Each observer's update method is called with the current state of the observable

Method Details

add

default void add(O observer)

Adds the given observer to the list of observers

Parameters:

observer - the observer to be added

addAll

default void addAll(Collection<O> observers)

Adds the given observers to the list of observers

Parameters:

observers - the observers to be added

getObservable

T getObservable()

Gets the observable object, which is the object being observed for state changes

Returns:

the observable object

setObservable

void setObservable(T observable)

Sets the observable object, which is the object being observed for state changes

Parameters:

observable - the new observable object

getObservers

List<O> getObservers()

Gets the list of observers that wish to be notified of changes to the observable object

Returns:

the list of observers

remove

default void remove(O observer)

Removes the given observer from the list of observers

Parameters:

observer - the observer to be removed

removeAll

default void removeAll(Collection<O> observers)

Removes the given observers from the list of observers

Parameters:

observers - the observers to be removed

updateObservers

default void updateObservers()

Notifies all observers of a change in the state of the observable object Each observer's update method is called with the current state of the observable