com.threerings.gwt.util

Class Value<T>

java.lang.Object

com.threerings.gwt.util.Value<T>

public class Value<T>
extends Object

Contains a changing value and provides a mechanism for listeners to react to changes to the value.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Value.Listener<T> Used to hear about changes to the value.

Constructor Summary

Constructors

Constructor and Description
Value(T init) Creates a new value with the specified initial value.

Method Summary

Methods

Modifier and Type	Method and Description
void	addListener(Value.Listener<T> listener) Adds a listener which will subsequently be notified when this value changes.
void	addListenerAndTrigger(Value.Listener<T> listener) Adds a listener and immediately triggers it with our current value.
static <T> Value<T>	create(T value) Creates a new value with the specified initial value.
T	get() Returns the current value.
<M> Value<M>	map(Function<T,M> func) Creates a value that maps this value via a function.
void	removeListener(Value.Listener<T> listener) Removes a listener from this value.
void	update(T value) Updates this value and notifies all listeners.
void	updateIf(T value) Updates this value and notifies all listeners if the supplied value differs from the current value (via the Object.equals(java.lang.Object) contract).

Methods inherited from class java.lang.Object

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

Constructor Detail

Value

public Value(T init)

Creates a new value with the specified initial value.

Method Detail

create

public static <T> Value<T> create(T value)

Creates a new value with the specified initial value.

addListener

public void addListener(Value.Listener<T> listener)

Adds a listener which will subsequently be notified when this value changes.

addListenerAndTrigger

public void addListenerAndTrigger(Value.Listener<T> listener)

Adds a listener and immediately triggers it with our current value.

removeListener

public void removeListener(Value.Listener<T> listener)

Removes a listener from this value.

get

public T get()

Returns the current value.

update

public void update(T value)

Updates this value and notifies all listeners. This will notify the listeners regardless of whether the supplied value differs from the current value.

updateIf

public void updateIf(T value)

Updates this value and notifies all listeners if the supplied value differs from the current value (via the Object.equals(java.lang.Object) contract).

map

public <M> Value<M> map(Function<T,M> func)

Creates a value that maps this value via a function. Every time the target value is updated the mapped value will be updated, regardless of whether or not the mapped value differs. The returned value will be a view and reject attempts to call update(T).