com.google.gwt.event.logical.shared
Class ValueChangeEvent<I>

java.lang.Object
  com.google.gwt.event.shared.GwtEvent<ValueChangeHandler<I>>
      com.google.gwt.event.logical.shared.ValueChangeEvent<I>

Type Parameters:

I - the value about to be changed

public class ValueChangeEvent<I>
extends GwtEvent<ValueChangeHandler<I>>

Represents a value change event.

ValueChangeEvent

protected ValueChangeEvent(I value)

Creates a value change event.

Parameters:

value - the value

fire

public static <I> void fire(HasValueChangeHandlers<I> source,
                            I value)

Fires a value change event on all registered handlers in the handler manager.If no such handlers exist, this method will do nothing.

Type Parameters:

I - the old value type

Parameters:

source - the source of the handlers

value - the value

fireIfNotEqual

public static <I> void fireIfNotEqual(HasValueChangeHandlers<I> source,
                                      I oldValue,
                                      I newValue)

Fires value change event if the old value is not equal to the new value. Use this call rather than making the decision to short circuit yourself for safe handling of null.

Type Parameters:

I - the old value type

Parameters:

source - the source of the handlers

oldValue - the oldValue, may be null

newValue - the newValue, may be null

getType

public static GwtEvent.Type<ValueChangeHandler<?>> getType()

Gets the type associated with this event.

Returns:

returns the handler type

shouldFire

protected static <I> boolean shouldFire(HasValueChangeHandlers<I> source,
                                        I oldValue,
                                        I newValue)

Convenience method to allow subtypes to know when they should fire a value change event in a null-safe manner.

Type Parameters:

I - value type

Parameters:

source - the source

oldValue - the old value

newValue - the new value

Returns:

whether the event should be fired

getAssociatedType

public final GwtEvent.Type<ValueChangeHandler<I>> getAssociatedType()

Description copied from class: GwtEvent

Returns the type used to register this event. Used by handler manager to dispatch events to the correct handlers.

Specified by:

getAssociatedType in class GwtEvent<ValueChangeHandler<I>>

Returns:

the type

getValue

public I getValue()

Gets the value.

Returns:

the value

toDebugString

public java.lang.String toDebugString()

Description copied from class: GwtEvent

This is a method used primarily for debugging. It gives a string representation of the event details. This does not override the toString method because the compiler cannot always optimize toString out correctly. Event types should override as desired.

Overrides:

toDebugString in class GwtEvent<ValueChangeHandler<I>>

Returns:

a string representing the event's specifics.

dispatch

protected void dispatch(ValueChangeHandler<I> handler)

Description copied from class: GwtEvent

Should only be called by HandlerManager. In other words, do not use or call.

Specified by:

dispatch in class GwtEvent<ValueChangeHandler<I>>

Parameters:

handler - handler