Class ObservableValueFromObservableCollection<T,U>

java.lang.Object

org.aksw.commons.collection.observable.ObservableValueFromObservableCollection<T,U>

Type Parameters:

T -

All Implemented Interfaces:

SingleValuedAccessor<T>, ObservableValue<T>

public class ObservableValueFromObservableCollection<T,U>
extends Object
implements ObservableValue<T>

Getter/setter view over an observable collection. If that collection has a single item then get() method returns it. Otherwise, if there are no or multiple items then the method returns null.

Author:

raven

Field Summary

Fields

Modifier and Type	Field	Description
protected ObservableCollection<U>	delegate
protected Function<? super T, ? extends U>	valueToItem
protected Function<? super Collection<? extends U>, ? extends T>	xform

Constructor Summary

Constructors

Constructor	Description
ObservableValueFromObservableCollection(ObservableCollection<U> delegate, Function<? super Collection<? extends U>, ? extends T> xform, Function<? super T, ? extends U> valueToItem)

Method Summary

Modifier and Type	Method	Description
Registration	addPropertyChangeListener(PropertyChangeListener listener)
Runnable	addVetoableChangeListener(VetoableChangeListener listener)
static <T> ObservableValue<T>	decorate(ObservableCollection<T> delegate)
T	get()	Attempt to get the only element from the underlying collection.
static <T> T	getOnlyElementOrNull(Iterable<T> iterable)
void	set(T value)	First clear the underlying collection.
static <T,U> PropertyChangeListener	wrapListener(Object self, PropertyChangeListener listener, Function<? super Collection<? extends U>, ? extends T> xform)	Wrap the listener so that the set-based property change event is converted to a single value based on

Methods inherited from class Object

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

Methods inherited from interface ObservableValue

addValueChangeListener, addVetoableChangeListener, convert

Methods inherited from interface SingleValuedAccessor

getOrDefault

Field Details

delegate

protected ObservableCollection<U> delegate

xform

protected Function<? super Collection<? extends U>, ? extends T> xform

valueToItem

protected Function<? super T, ? extends U> valueToItem

Constructor Details

ObservableValueFromObservableCollection

public ObservableValueFromObservableCollection(ObservableCollection<U> delegate,
 Function<? super Collection<? extends U>, ? extends T> xform,
 Function<? super T, ? extends U> valueToItem)

Method Details

getOnlyElementOrNull

public static <T> T getOnlyElementOrNull(Iterable<T> iterable)

get

public T get()

Attempt to get the only element from the underlying collection. If that collection is empty or contains multiple (possible equal) elements then return null.

Specified by:

get in interface SingleValuedAccessor<T>

set

public void set(T value)

First clear the underlying collection. If the given value is non-null then add it to the collection.

Specified by:

set in interface SingleValuedAccessor<T>

wrapListener

public static <T,U> PropertyChangeListener wrapListener(Object self,
 PropertyChangeListener listener,
 Function<? super Collection<? extends U>, ? extends T> xform)

Wrap the listener so that the set-based property change event is converted to a single value based on

addPropertyChangeListener

public Registration addPropertyChangeListener(PropertyChangeListener listener)

Specified by:

addPropertyChangeListener in interface ObservableValue<T>

addVetoableChangeListener

public Runnable addVetoableChangeListener(VetoableChangeListener listener)

Specified by:

addVetoableChangeListener in interface ObservableValue<T>

decorate

public static <T> ObservableValue<T> decorate(ObservableCollection<T> delegate)