hu.akarnokd.reactive4java.util

Class DefaultObservable<T>

java.lang.Object

hu.akarnokd.reactive4java.util.DefaultObservable<T>

Type Parameters:

T - the element type of the observable.

All Implemented Interfaces:

BaseObserver, CloseableObservable<T>, Observable<T>, Observer<T>, Subject<T,T>, java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

DefaultGroupedObservable, ObservableActionListener, ObservableAdjustmentListener, ObservableChangeListener, ObservableDocumentListener, ObservableItemListener, ObservableKeyListener, ObservableListDataListener, ObservableListSelectionListener, ObservableMouseListener, ObservableWindowListener

public class DefaultObservable<T>
extends java.lang.Object
implements Subject<T,T>, CloseableObservable<T>

An observable + observer implementation which keeps track of the registered observers and common methods which dispatch events to all registered observers.

The implementation is thread safe: all default methods may be invoked from any thread. Could be used as a default implementation to convert between Observable and other event-listener type pattern.

The observer keeps track of the registered observer count and when it reaches zero again, the last deregister will invoke the close() method.

Override close() method if you need some resource cleanup. Note that this may happen on any thread.

The constructor lets you customize whether automatically deregister every observer after an error or finish message is relayed.

Constructor Summary

Constructors

Constructor and Description
DefaultObservable() Default constructor.
DefaultObservable(boolean unregisterOnFinish, boolean unregisterOnError) Constructor with the option to set the unregistration policies.

Method Summary

Modifier and Type	Method and Description
void	close()
void	error(java.lang.Throwable ex) An exception is received.
void	finish() No more values to expect.
int	getObserverCount()
void	next(T value) The next value is received.
java.io.Closeable	register(Observer<? super T> observer) Registers an observer for the notification of Ts.
protected void	unregister(java.io.Closeable handler) Unregister the observer belonging to the given handler.

Methods inherited from class java.lang.Object

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

Constructor Detail

DefaultObservable

public DefaultObservable()

Default constructor. All observers will be unregistered upon error() or finish().

DefaultObservable

public DefaultObservable(boolean unregisterOnFinish,
                         boolean unregisterOnError)

Constructor with the option to set the unregistration policies.

Parameters:

unregisterOnFinish - unregister all observers on a finish() call?

unregisterOnError - unregister all observers on an error() call?

Method Detail

error

public void error(@Nonnull
                  java.lang.Throwable ex)

Description copied from interface: BaseObserver

An exception is received.

Specified by:

error in interface BaseObserver

Parameters:

ex - the exception

finish

public void finish()

Description copied from interface: BaseObserver

No more values to expect.

Specified by:

finish in interface BaseObserver

next

public void next(T value)

Description copied from interface: Observer

The next value is received.

Specified by:

next in interface Observer<T>

Parameters:

value - the next value

register

@Nonnull
public java.io.Closeable register(@Nonnull
                                            Observer<? super T> observer)

Description copied from interface: Observable

Registers an observer for the notification of Ts.

Specified by:

register in interface Observable<T>

Parameters:

observer - the observer of Ts or any supertype of it

Returns:

the way of deregister the observer from this provider

unregister

protected void unregister(java.io.Closeable handler)

Unregister the observer belonging to the given handler. A handler can only be unregistered once

Parameters:

handler - the observer's handler

close

public void close()

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

getObserverCount

public int getObserverCount()

Returns:

Returns the current observer count.