Class EventDispatcher

java.lang.Object
com.codename1.ui.util.EventDispatcher
public class EventDispatcher extends Object

Handles event dispatching while guaranteeing that all events would be fired properly on the EDT regardless of their source. This class handles listener registration/removal in a safe and uniform way.

To integrate this into your code you can use something like:

private final EventDispatcher listeners = new EventDispatcher();

public void addActionListener(ActionListener a) {
    listeners.addListener(a);
}
public void removeActionListener(ActionListener a) {
    listeners.removeListener(a);
}
private void fireEvent(ActionEvent ev) {
    listeners.fireActionEvent(ev);
}

  • Constructor Summary

    Constructors
    Constructor
    Description
    EventDispatcher()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addListener(Object listener)
    Add a listener to the dispatcher that would receive the events when they occurs
    void
    fireActionEvent(ActionEvent ev)
    Fires the event safely on the EDT without risk of concurrency errors
    void
    fireBindTargetChange(Component source, String propertyName, Object oldValue, Object newValue)
    Fired when a property of the component changes to a new value
    void
    fireDataChangeEvent(int index, int type)
    Fires the event safely on the EDT without risk of concurrency errors
    void
    fireFocus(Component c)
    Fires the event safely on the EDT without risk of concurrency errors
    void
    fireScrollEvent(int scrollX, int scrollY, int oldscrollX, int oldscrollY)
    Fires the event safely on the EDT without risk of concurrency errors
    void
    fireSelectionEvent(int oldSelection, int newSelection)
    Fires the event safely on the EDT without risk of concurrency errors
    void
    fireStyleChangeEvent(String property, Style source)
    Fires the style change even to the listeners
    Collection
    getListenerCollection()
    Returns the collection of the listeners
    Vector
    getListenerVector()
    Returns the vector of the listeners
    boolean
    hasListeners()
    Returns true if the event dispatcher has registered listeners
    boolean
    isBlocking()
    Indicates whether this dispatcher blocks when firing events or not, normally a dispatcher uses callSeriallyAndWait() to be 100% synchronous with event delivery however this method is very slow.
    void
    removeListener(Object listener)
    Remove the listener from the dispatcher
    void
    setBlocking(boolean blocking)
    Indicates whether this dispatcher blocks when firing events or not, normally a dispatcher uses callSeriallyAndWait() to be 100% synchronous with event delivery however this method is very slow.
    static void
    setFireStyleEventsOnNonEDT(boolean fire)
    When set to true, style events will be dispatched even from non-EDT threads.

    Methods inherited from class Object

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

  • Constructor Details

    • EventDispatcher

      public EventDispatcher()

  • Method Details

    • setFireStyleEventsOnNonEDT

      public static void setFireStyleEventsOnNonEDT(boolean fire)

      When set to true, style events will be dispatched even from non-EDT threads. When set to false, when in non-EDT threads, style events will not be dispatched at all (And developer has to make sure changes will be reflected by calling revalidate after all the changes)

      Default is false. Setting this to true results in a performance penalty, and it is better instead to simply aggregate events performed on non-EDT threads and when all are over - call revalidate on the relevant container.

      Parameters
      • fire: true to fire on non-EDT, false otherwise

    • addListener

      public void addListener(Object listener)

      Add a listener to the dispatcher that would receive the events when they occurs

      Parameters
      • listener: a dispatcher listener to add

    • getListenerVector

      public Vector getListenerVector()

      Returns the vector of the listeners

      Returns

      the vector of listeners attached to the event dispatcher

      Deprecated

      use getListenerCollection instead, this method will now be VERY SLOW

    • getListenerCollection

      public Collection getListenerCollection()

      Returns the collection of the listeners

      Returns

      the collection of listeners attached to the event dispatcher

    • removeListener

      public void removeListener(Object listener)

      Remove the listener from the dispatcher

      Parameters
      • listener: a dispatcher listener to remove

    • fireDataChangeEvent

      public void fireDataChangeEvent(int index, int type)

      Fires the event safely on the EDT without risk of concurrency errors

      Parameters

      • index: the index of the event

      • type: the type of the event

    • fireBindTargetChange

      public void fireBindTargetChange(Component source, String propertyName, Object oldValue, Object newValue)

      Fired when a property of the component changes to a new value

      Parameters

      • source: the source component

      • propertyName: the name of the property

      • oldValue: the old value of the property

      • newValue: the new value for the property

    • fireStyleChangeEvent

      public void fireStyleChangeEvent(String property, Style source)

      Fires the style change even to the listeners

      Parameters

      • property: the property name for the event

      • source: the style firing the event

    • fireActionEvent

      public void fireActionEvent(ActionEvent ev)

      Fires the event safely on the EDT without risk of concurrency errors

      Parameters
      • ev: the ActionEvent to fire to the listeners

    • fireSelectionEvent

      public void fireSelectionEvent(int oldSelection, int newSelection)

      Fires the event safely on the EDT without risk of concurrency errors

      Parameters

      • oldSelection: old selection

      • newSelection: new selection

    • fireScrollEvent

      public void fireScrollEvent(int scrollX, int scrollY, int oldscrollX, int oldscrollY)
      Fires the event safely on the EDT without risk of concurrency errors

    • fireFocus

      public void fireFocus(Component c)

      Fires the event safely on the EDT without risk of concurrency errors

      Parameters
      • c: the Component that gets the focus event

    • hasListeners

      public boolean hasListeners()

      Returns true if the event dispatcher has registered listeners

      Returns

      true if the event dispatcher has registered listeners

    • isBlocking

      public boolean isBlocking()

      Indicates whether this dispatcher blocks when firing events or not, normally a dispatcher uses callSeriallyAndWait() to be 100% synchronous with event delivery however this method is very slow. By setting blocking to false the callSerially method is used which allows much faster execution for IO heavy operations.

      Returns

      the blocking state

    • setBlocking

      public void setBlocking(boolean blocking)

      Indicates whether this dispatcher blocks when firing events or not, normally a dispatcher uses callSeriallyAndWait() to be 100% synchronous with event delivery however this method is very slow. By setting blocking to false the callSerially method is used which allows much faster execution for IO heavy operations.

      Parameters
      • blocking: the blocking value