HandlerManager (Google Web Toolkit Javadoc)

java.lang.Object
- com.google.gwt.event.shared.HandlerManager

All Implemented Interfaces:

HasHandlers
```
public class HandlerManager
extends java.lang.Object
implements HasHandlers
```
Manager responsible for adding handlers to event sources and firing those handlers on passed in events. Primitive ancestor of EventBus, and used at the core of {com.google.gwt.user.client.ui.Widget}.
While widget authors should continue to use Widget.addDomHandler(EventHandler, com.google.gwt.event.dom.client.DomEvent.Type) and Widget.addHandler(EventHandler, com.google.gwt.event.shared.GwtEvent.Type) , application developers are strongly discouraged from using a HandlerManager instance as a global event dispatch mechanism.

Constructor Summary

Constructors
Constructor and Description
`HandlerManager(java.lang.Object source)` Creates a handler manager with a source to be set on all events fired via `fireEvent(GwtEvent)`.
`HandlerManager(java.lang.Object source, boolean fireInReverseOrder)` Creates a handler manager with the given source, specifying the order in which handlers are fired.

Method Summary

Methods
Modifier and Type	Method and Description
`<H extends EventHandler> HandlerRegistration`	`addHandler(GwtEvent.Type<H> type, H handler)` Adds a handler.
`void`	`fireEvent(GwtEvent<?> event)` Fires the given event to the handlers listening to the event's type.
`<H extends EventHandler> H`	`getHandler(GwtEvent.Type<H> type, int index)` Gets the handler at the given index.
`int`	`getHandlerCount(GwtEvent.Type<?> type)` Gets the number of handlers listening to the event type.
`boolean`	`isEventHandled(GwtEvent.Type<?> e)` Does this handler manager handle the given event type?
`<H extends EventHandler> void`	`removeHandler(GwtEvent.Type<H> type, H handler)` Removes the given handler from the specified event type.

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

- Constructor Detail
  - HandlerManager
```
public HandlerManager(java.lang.Object source)
```
    Creates a handler manager with a source to be set on all events fired via fireEvent(GwtEvent). Handlers will be fired in the order that they are added.
    
    Parameters:
    source - the default event source
  - HandlerManager
```
public HandlerManager(java.lang.Object source,
              boolean fireInReverseOrder)
```
    Creates a handler manager with the given source, specifying the order in which handlers are fired.
    
    Parameters:
    source - the event source
    fireInReverseOrder - true to fire handlers in reverse order
- Method Detail
  - addHandler
```
public <H extends EventHandler> HandlerRegistration addHandler(GwtEvent.Type<H> type,
                                                      H handler)
```
    Adds a handler.
    
    Type Parameters:
    H - The type of handler
    Parameters:
    type - the event type associated with this handler
    handler - the handler
    
    Returns:
    the handler registration, can be stored in order to remove the handler later
  - fireEvent
```
public void fireEvent(GwtEvent<?> event)
```
    Fires the given event to the handlers listening to the event's type.
    Any exceptions thrown by handlers will be bundled into a UmbrellaException and then re-thrown after all handlers have completed. An exception thrown by a handler will not prevent other handlers from executing.
    Note, any subclass should be very careful about overriding this method, as adds/removes of handlers will not be safe except within this implementation.
    
    Specified by:
    
    fireEvent in interface HasHandlers
    
    Parameters:
    event - the event
  - getHandler
```
public <H extends EventHandler> H getHandler(GwtEvent.Type<H> type,
                                    int index)
```
    Gets the handler at the given index.
    
    Type Parameters:
    H - the event handler type
    Parameters:
    index - the index
    type - the handler's event type
    
    Returns:
    the given handler
  - getHandlerCount
```
public int getHandlerCount(GwtEvent.Type<?> type)
```
    Gets the number of handlers listening to the event type.
    
    Parameters:
    type - the event type
    
    Returns:
    the number of registered handlers
  - isEventHandled
```
public boolean isEventHandled(GwtEvent.Type<?> e)
```
    Does this handler manager handle the given event type?
    
    Parameters:
    e - the event type
    
    Returns:
    whether the given event type is handled
  - removeHandler
```
public <H extends EventHandler> void removeHandler(GwtEvent.Type<H> type,
                                          H handler)
```
    Removes the given handler from the specified event type.
    
    Type Parameters:
    H - handler type
    Parameters:
    type - the event type
    handler - the handler

Class HandlerManager

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

HandlerManager

HandlerManager

Method Detail

addHandler

fireEvent

getHandler

getHandlerCount

isEventHandled

removeHandler