java.lang.Object
- io.github.mmm.event.AbstractEventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
- - io.github.mmm.value.observable.AbstractObservableValue<V>

Type Parameters:

V - type of the observable value.

All Implemented Interfaces:

EventSource<ObservableEvent<V>,ObservableEventListener<? super V>>, ObservableValue<V>, ReadableValue<V>, Supplier<V>

Direct Known Subclasses:

AbstractWritableObservableValue, Binding
```
public abstract class AbstractObservableValue<V>
extends AbstractEventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
implements ObservableValue<V>
```
Abstract base implementation of ObservableValue that handles ObservableEventListeners.

Since:

1.0.0

Constructor Summary

Constructors
Constructor Description

AbstractObservableValue()
The constructor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`addListener(ObservableEventListener<? super V> listener, boolean weak)`	Adds an `EventListener` which will be notified whenever the an event occurs (something changes).
`protected void`	`fireChange(Object change)`	Fires a default `value change` event.
`protected void`	`fireEvent()`	Fires a default value change event.
`protected void`	`fireEvent(ObservableEvent<V> event)`
`protected void`	`fireEventFor(AbstractObservableValue<?> observable)`
`protected <T> void`	`fireEventFor(AbstractObservableValue<T> observable, ObservableEvent<T> event)`
`protected void`	`fireEventWithOldValue(V oldValue)`	Fires a default value change event if the `old value` is known (currently available anyhow).
`protected boolean`	`hasChangeAwareListeners()`
`protected void`	`invalidate()`	Invalidates this observable in case it's value is computed.
`boolean`	`removeListener(ObservableEventListener<? super V> listener)`	This method removes an `EventListener`.
`String`	`toString()`
`void`	`toString(StringBuilder sb)`

Methods inherited from class io.github.mmm.event.AbstractEventSource
getEventAdapter, hasListeners

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.github.mmm.event.EventSource
addListener, addWeakListener

Methods inherited from interface io.github.mmm.value.ReadableValue
get, getSafe

- Constructor Detail
  - AbstractObservableValue
```
public AbstractObservableValue()
```
    The constructor.
- Method Detail
  - addListener
```
public void addListener(ObservableEventListener<? super V> listener,
                        boolean weak)
```
    Description copied from interface: EventSource
    
    Adds an EventListener which will be notified whenever the an event occurs (something changes). If the same listener is added more than once, it will be notified more than once. The same EventListener instance may be registered for different EventSources.
    
    Specified by:
    
    addListener in interface EventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
    
    Overrides:
    
    addListener in class AbstractEventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
    
    Parameters:
    
    listener - the EventListener to register.
    
    weak - - true if the EventListener may be garbage collected without being removed via a WeakReference, false otherwise (if the listener will be associated using a strong reference). When providing true here (use WeakReference), you need to store a reference to your registered EventListener yourself in the owning parent object so it is not garbage-collected too early.
    
    See Also:
    
    EventSource.addWeakListener(EventListener)
  - removeListener
```
public boolean removeListener(ObservableEventListener<? super V> listener)
```
    Description copied from interface: EventSource
    
    This method removes an EventListener. If the EventListener was not registered before this method does not do any change. Otherwise the first matching EventListener will be removed. So if you added an EventListener multiple times, only the first occurrence will be removed.
    For performance reasons EventListener.isMatchedUsingEquals() returns false by default. To force the usage of equals instead, ensure your EventListener implementation overrides Object.equals(Object) and EventListener.isMatchedUsingEquals() returning true.
    
    Specified by:
    
    removeListener in interface EventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
    
    Overrides:
    
    removeListener in class AbstractEventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
    
    Parameters:
    
    listener - is the EventListener to unregister.
    
    Returns:
    
    true if the given listener has successfully been removed, false if the listener was NOT registered.
  - hasChangeAwareListeners
```
protected boolean hasChangeAwareListeners()
```
    Returns:
    
    true if at least one ChangeAwareObservableEventListener is registered, false otherwise (to avoid building and sending changes for better performance).
  - fireEvent
```
protected void fireEvent()
```
    Fires a default value change event.
    
    See Also:
    
    fireEvent(ObservableEvent)
  - fireEventWithOldValue
```
protected void fireEventWithOldValue(V oldValue)
```
    Fires a default value change event if the old value is known (currently available anyhow).
    
    Parameters:
    
    oldValue - the old value. May be null.
    
    See Also:
    
    fireEvent(ObservableEvent)
  - fireChange
```
protected void fireChange(Object change)
```
    Fires a default value change event.
    
    Parameters:
    
    change - the change.
    
    See Also:
    
    fireEvent(ObservableEvent)
  - fireEvent
```
protected void fireEvent(ObservableEvent<V> event)
```
    Overrides:
    
    fireEvent in class AbstractEventSource<ObservableEvent<V>,ObservableEventListener<? super V>>
    
    Parameters:
    
    event - the event to send to all registered EventListeners.
  - fireEventFor
```
protected <T> void fireEventFor(AbstractObservableValue<T> observable,
                                ObservableEvent<T> event)
```
    Type Parameters:
    
    T - type of the observable value.
    
    Parameters:
    
    observable - the AbstractObservableValue where to invoke fireEvent(ObservableEvent) (if prevented due to visibility issues).
    
    event - the ObservableEvent to send.
  - fireEventFor
```
protected void fireEventFor(AbstractObservableValue<?> observable)
```
    Parameters:
    
    observable - the AbstractObservableValue where to invoke fireEvent() (if prevented due to visibility issues).
  - invalidate
```
protected void invalidate()
```
    Invalidates this observable in case it's value is computed.
  - toString
```
public final String toString()
```
    Overrides:
    
    toString in class Object
  - toString
```
public void toString(StringBuilder sb)
```
    Specified by:
    
    toString in interface ObservableValue<V>
    
    Parameters:
    
    sb - the StringBuilder where to append the details of this property for toString()-Representation.

Class AbstractObservableValue<V>

Constructor Summary

Method Summary

Methods inherited from class io.github.mmm.event.AbstractEventSource

Methods inherited from class java.lang.Object

Methods inherited from interface io.github.mmm.event.EventSource

Methods inherited from interface io.github.mmm.value.ReadableValue

Constructor Detail

AbstractObservableValue

Method Detail

addListener

removeListener

hasChangeAwareListeners

fireEvent

fireEventWithOldValue

fireChange

fireEvent

fireEventFor

fireEventFor

invalidate

toString

toString