eu.webtoolkit.jwt
Class AbstractEventSignal

java.lang.Object
  eu.webtoolkit.jwt.AbstractSignal
      eu.webtoolkit.jwt.AbstractEventSignal

Direct Known Subclasses:

AbstractJSignal, EventSignal, EventSignal1

public abstract class AbstractEventSignal
extends AbstractSignal

Abstract base class for event signals.

Event signals are signals that may be triggered from the browser. Listeners that are added to this signal may be implemented in Java only or in JavaScript only or have both Java and JavaScript implementations.

Nested Class Summary

static class	AbstractEventSignal.AutoLearnListener A listener whose JavaScript behavior is learned on its first invocation.
static class	AbstractEventSignal.JavaScriptListener A JavaScript-only listener.
static class	AbstractEventSignal.LearningListener An abstract base class for a listener with (learned) JavaScript behavior.
static class	AbstractEventSignal.PreLearnListener A listener whose JavaScript behavior is learned in advance.

Nested classes/interfaces inherited from class eu.webtoolkit.jwt.AbstractSignal

AbstractSignal.Connection

Method Summary

void	addListener(JSlot slot) Adds a JavaScript event listener.
void	addListener(java.lang.String javascript) Adds a JavaScript event listener.
void	addListener(WObject listenerOwner, AbstractEventSignal.AutoLearnListener listener) Adds a learning listener to this signal.
void	addListener(WObject listenerOwner, AbstractEventSignal.JavaScriptListener listener) Adds a learning listener to this signal.
void	addListener(WObject listenerOwner, AbstractEventSignal.LearningListener listener) Adds a learning listener to this signal.
void	addListener(WObject listenerOwner, AbstractEventSignal.PreLearnListener listener) Adds a learning listener to this signal.
protected java.lang.String	createUserEventCall(java.lang.String jsObject, java.lang.String jsEvent, java.lang.String name, java.lang.String arg1, java.lang.String arg2, java.lang.String arg3, java.lang.String arg4, java.lang.String arg5, java.lang.String arg6)
void	disconnect(AbstractSignal.Connection connection)
protected int	getListenerCount() Returns the number of connected listeners.
boolean	isConnected() Returns whether at least one event listener has been connected to this signal.
boolean	isDefaultActionPrevented() Returns whether propagation of the event is prevented.
boolean	isPropagationPrevented() Returns whether the default action is prevented.
void	preventDefaultAction() Prevents the default action associated with this event.
void	preventDefaultAction(boolean prevent) Prevents the default action associated with this event.
void	preventPropagation() Prevents the default action associated with this event.
void	preventPropagation(boolean prevent) Prevents the default action associated with this event.
void	removeListener(AbstractEventSignal.LearningListener listener) Remove a learning listener from this signal.
void	trigger() Triggers the signal.

Methods inherited from class eu.webtoolkit.jwt.AbstractSignal

addListener, getListeners, isBlocked, removeListener, setBlocked

Methods inherited from class java.lang.Object

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

Method Detail

addListener

public void addListener(WObject listenerOwner,
                        AbstractEventSignal.LearningListener listener)

Adds a learning listener to this signal.

An owner object may be passed when the listener is implemented using an anonymous inner class. In that case the owner object should be the enclosing object of the listener object, and this is used to bind the lifetime of the listener: when the owner object is garbage collected, the listener will be freed as well. This avoids the most common reason for memory leaks in Java implementations of the Observer pattern: the owner object will not get garbage collected because of the (anonymous) listener object having a reference to it, even if the receiver object is no longer referenced from anywhere. When the owner object is not null, the listener is stored using a strong reference in the owner object, and using a weak reference in the signal. Note: The receiver is currently not yet used.

Parameters:

listenerOwner - if not null, the enclosing object for an anonymous listener

listener - the listener

addListener

public void addListener(WObject listenerOwner,
                        AbstractEventSignal.AutoLearnListener listener)

Adds a learning listener to this signal.

See Also:

addListener(WObject, LearningListener)

addListener

public void addListener(WObject listenerOwner,
                        AbstractEventSignal.PreLearnListener listener)

Adds a learning listener to this signal.

See Also:

addListener(WObject, LearningListener)

addListener

public void addListener(WObject listenerOwner,
                        AbstractEventSignal.JavaScriptListener listener)

Adds a learning listener to this signal.

See Also:

addListener(WObject, LearningListener)

removeListener

public void removeListener(AbstractEventSignal.LearningListener listener)

Remove a learning listener from this signal.

Parameters:

listener - a learning listener that was previously added

getListenerCount

protected int getListenerCount()

Description copied from class: AbstractSignal

Returns the number of connected listeners.

Overrides:

getListenerCount in class AbstractSignal

Returns:

the number of connected listeners.

isConnected

public boolean isConnected()

Description copied from class: AbstractSignal

Returns whether at least one event listener has been connected to this signal.

Overrides:

isConnected in class AbstractSignal

Returns:

whether at least one event listener has been connected to this signal.

isPropagationPrevented

public boolean isPropagationPrevented()

Returns whether the default action is prevented.

Returns:

whether the default action is prevented.

See Also:

preventPropagation(boolean)

isDefaultActionPrevented

public boolean isDefaultActionPrevented()

Returns whether propagation of the event is prevented.

Returns:

whether the default action is prevented.

See Also:

preventDefaultAction(boolean)

trigger

public void trigger()

Triggers the signal.

The AbstractEventSignal.LearningListener.trigger() method of all listeners added to this signal are triggered.

addListener

public void addListener(JSlot slot)

Adds a JavaScript event listener.

Parameters:

slot - the JavaScript event listener

addListener

public void addListener(java.lang.String javascript)

Adds a JavaScript event listener. This adds a listener that is implemented solely as a client-side JavaScript function. The argument is a JavaScript function which optionally accepts a DOM element and the event:

   function(element, event)
   {
      ...
   }
 

Parameters:

javascript - the JavaScript function.

preventDefaultAction

public void preventDefaultAction(boolean prevent)

Prevents the default action associated with this event.

This prevents the default browser action associated with this event.

Parameters:

prevent - whether the default action should be prevented.

preventDefaultAction

public void preventDefaultAction()

Prevents the default action associated with this event.

This prevents the default browser action associated with this event.

preventPropagation

public void preventPropagation(boolean prevent)

Prevents the default action associated with this event.

This prevents the event propagation to ancestors.

Parameters:

prevent - whether the default action should be prevented.

preventPropagation

public final void preventPropagation()

Prevents the default action associated with this event.

This prevents both the default browser action associated with this event as well as the event bubbling up or cascading its hierarchy.

disconnect

public void disconnect(AbstractSignal.Connection connection)

createUserEventCall

protected java.lang.String createUserEventCall(java.lang.String jsObject,
                                               java.lang.String jsEvent,
                                               java.lang.String name,
                                               java.lang.String arg1,
                                               java.lang.String arg2,
                                               java.lang.String arg3,
                                               java.lang.String arg4,
                                               java.lang.String arg5,
                                               java.lang.String arg6)