Package org.eclipse.core.databinding.observable.value

Class AbstractObservableValue<T>

java.lang.Object

org.eclipse.core.databinding.observable.AbstractObservable

org.eclipse.core.databinding.observable.value.AbstractObservableValue<T>

Type Parameters:

T - the type of value being observed

All Implemented Interfaces:

IObservable, IObservableValue<T>

Direct Known Subclasses:

AbstractVetoableValue, ComputedValue, DateAndTimeObservableValue, DuplexingObservableValue, LocalDateTimeObservableValue, SelectObservableValue, WritableValue

public abstract class AbstractObservableValue<T>
extends AbstractObservable
implements IObservableValue<T>

This class is thread safe. All state accessing methods must be invoked from the current realm. Methods for adding and removing listeners may be invoked from any thread.

Since:

1.0

Implementation Note:

If methods are added to the interface which this class implements then implementations of those methods must be added to this class.

Constructor Summary

Constructors

Constructor	Description
AbstractObservableValue()	Constructs a new instance with the default realm.
AbstractObservableValue(Realm realm)

Method Summary

Modifier and Type	Method	Description
protected void	addListener(Object listenerType, IObservablesListener listener)
void	addValueChangeListener(IValueChangeListener<? super T> listener)
protected Object	clone()
protected abstract T	doGetValue()
protected void	doSetValue(T value)	Template method for setting the value of the observable.
protected void	fireChange()
protected void	fireEvent(ObservableEvent event)
protected void	fireValueChange(ValueDiff<T> diff)
protected void	firstListenerAdded()
Realm	getRealm()
T	getValue()	Returns the value.
protected boolean	hasListeners()
boolean	isStale()	Returns whether the state of this observable is stale and is expected to change soon.
protected void	lastListenerRemoved()
protected void	removeListener(Object listenerType, IObservablesListener listener)
void	removeValueChangeListener(IValueChangeListener<? super T> listener)
void	setValue(T value)	Sets the value.

Methods inherited from class org.eclipse.core.databinding.observable.AbstractObservable

addChangeListener, addDisposeListener, addStaleListener, checkRealm, dispose, fireStale, isDisposed, removeChangeListener, removeDisposeListener, removeStaleListener

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.core.databinding.observable.IObservable

addChangeListener, addDisposeListener, addStaleListener, dispose, getRealm, isDisposed, removeChangeListener, removeDisposeListener, removeStaleListener

Methods inherited from interface org.eclipse.core.databinding.observable.value.IObservableValue

getValueType

Constructor Detail

AbstractObservableValue

public AbstractObservableValue()

Constructs a new instance with the default realm.

AbstractObservableValue

public AbstractObservableValue(Realm realm)

Parameters:

realm - the realm to use; not null

Method Detail

addValueChangeListener

public void addValueChangeListener(IValueChangeListener<? super T> listener)

Specified by:

addValueChangeListener in interface IObservableValue<T>

Parameters:

listener - the change listener to add; not null

removeValueChangeListener

public void removeValueChangeListener(IValueChangeListener<? super T> listener)

Specified by:

removeValueChangeListener in interface IObservableValue<T>

Parameters:

listener - the change listener to remove; not null

setValue

public final void setValue(T value)

Description copied from interface: IObservableValue

Sets the value. Must be invoked in the Realm of the observable.

Specified by:

setValue in interface IObservableValue<T>

Parameters:

value - the value to set

doSetValue

protected void doSetValue(T value)

Template method for setting the value of the observable. By default the method throws an UnsupportedOperationException.

Parameters:

value - the value to set

fireValueChange

protected void fireValueChange(ValueDiff<T> diff)

getValue

public final T getValue()

Description copied from interface: IObservableValue

Returns the value. Must be invoked in the Realm of the observable.

Specified by:

getValue in interface IObservableValue<T>

Returns:

the current value

doGetValue

protected abstract T doGetValue()

isStale

public boolean isStale()

Description copied from interface: IObservable

Returns whether the state of this observable is stale and is expected to change soon. A non-stale observable that becomes stale will notify its stale listeners. A stale object that becomes non-stale does so by changing its state and notifying its change listeners, it does not notify its stale listeners about becoming non-stale. Clients that do not expect asynchronous changes may ignore staleness of observable objects.

Specified by:

isStale in interface IObservable

Returns:

true if this observable's state is stale and will change soon.

fireChange

protected void fireChange()

Overrides:

fireChange in class AbstractObservable

addListener

protected void addListener(Object listenerType,
                           IObservablesListener listener)

Parameters:

listenerType - arbitrary object to identify a type of the listener

listener - the listener to add; not null

removeListener

protected void removeListener(Object listenerType,
                              IObservablesListener listener)

Parameters:

listenerType - arbitrary object to identify a type of the listener

listener - the listener to remove; not null

hasListeners

protected boolean hasListeners()

fireEvent

protected void fireEvent(ObservableEvent event)

firstListenerAdded

protected void firstListenerAdded()

lastListenerRemoved

protected void lastListenerRemoved()

getRealm

public Realm getRealm()

Returns:

Returns the realm.

clone

protected Object clone()
                throws CloneNotSupportedException

Overrides:

clone in class Object

Throws:

CloneNotSupportedException