/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores
* CA 94065 USA or visit www.oracle.com if you need additional information or
* have any questions.
*/
package com.codename1.ui.util;
import com.codename1.cloud.BindTarget;
import com.codename1.ui.*;
import com.codename1.ui.events.*;
import com.codename1.ui.plaf.Style;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Vector;
/**
* <p>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. </p>
* <p>
* To integrate this into your code you can use something like:
* </p>
* <script src="https://gist.github.com/codenameone/8abb07271bae62d0f81a.js"></script>
*
* @author Shai Almog
*/
public class EventDispatcher {
private boolean blocking = false;
private ArrayList<Object> listeners;
boolean actionListenerArray;
boolean styleListenerArray;
boolean bindTargetArray;
boolean dataChangeListenerArray;
boolean focusListenerArray;
boolean selectionListenerArray;
boolean scrollListenerArray;
private static boolean fireStyleEventsOnNonEDT = false;
/**
* 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.
*
* @param fire true to fire on non-EDT, false otherwise
*/
public static void setFireStyleEventsOnNonEDT(boolean fire) {
fireStyleEventsOnNonEDT = fire;
}
class CallbackClass implements Runnable {
private Object[] iPending;
private Object iPendingEvent;
public CallbackClass(Object[] iPending, Object iPendingEvent) {
this.iPending = iPending;
this.iPendingEvent = iPendingEvent;
}
/**
* Do not invoke this method it handles the dispatching internally and serves
* as an implementation detail
*/
public final void run() {
if(!Display.getInstance().isEdt()) {
throw new IllegalStateException("This method should not be invoked by external code!");
}
if(styleListenerArray) {
Object[] p = (Object[])iPendingEvent;
fireStyleChangeSync((StyleListener[])iPending, (String)p[0], (Style)p[1]);
return;
}
if(actionListenerArray) {
fireActionSync((ActionListener[])iPending, (ActionEvent)iPendingEvent);
return;
}
if(focusListenerArray) {
fireFocusSync((FocusListener[])iPending, (Component)iPendingEvent);
return;
}
if(dataChangeListenerArray) {
fireDataChangeSync((DataChangedListener[])iPending, ((int[])iPendingEvent)[0], ((int[])iPendingEvent)[1]);
return;
}
if(selectionListenerArray) {
fireSelectionSync((SelectionListener[])iPending, ((int[])iPendingEvent)[0], ((int[])iPendingEvent)[1]);
return;
}
if(scrollListenerArray) {
fireScrollSync((ScrollListener[])iPending, ((int[])iPendingEvent)[0], ((int[])iPendingEvent)[1], ((int[])iPendingEvent)[2], ((int[])iPendingEvent)[3]);
return;
}
if(bindTargetArray) {
Object[] a = (Object[])iPendingEvent;
fireBindTargetChangeSync((BindTarget[])iPending, (Component)a[0], (String)a[1], a[2], a[3]);
return;
}
}
};
/**
* Add a listener to the dispatcher that would receive the events when they occurs
*
* @param listener a dispatcher listener to add
*/
public synchronized void addListener(Object listener) {
if(listener != null) {
if(listeners == null) {
listeners = new ArrayList<Object>();
}
if(!listeners.contains(listener)){
listeners.add(listener);
}
}
}
/**
* Returns the vector of the listeners
*
* @return the vector of listeners attached to the event dispatcher
* @deprecated use getListenerCollection instead, this method will now be VERY SLOW
*/
public Vector getListenerVector() {
return new Vector(listeners);
}
/**
* Returns the collection of the listeners
*
* @return the collection of listeners attached to the event dispatcher
*/
public Collection getListenerCollection() {
return listeners;
}
/**
* Remove the listener from the dispatcher
*
* @param listener a dispatcher listener to remove
*/
public synchronized void removeListener(Object listener) {
if(listeners != null) {
listeners.remove(listener);
}
}
/**
* Fires the event safely on the EDT without risk of concurrency errors
*
* @param index the index of the event
* @param type the type of the event
*/
public void fireDataChangeEvent(int index, int type) {
if(listeners == null || listeners.size() == 0) {
return;
}
boolean isEdt = Display.getInstance().isEdt();
// minor optimization for a common use case to avoid allocation costs
if(isEdt && listeners.size() == 1) {
DataChangedListener a = (DataChangedListener)listeners.get(0);
a.dataChanged(type, index);
return;
}
DataChangedListener[] array;
synchronized(this) {
array = new DataChangedListener[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (DataChangedListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireDataChangeSync(array, type, index);
} else {
dataChangeListenerArray = true;
Runnable cl = new CallbackClass(array, new int[] {type, index});
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Fired when a property of the component changes to a new value
*
* @param source the source component
* @param propertyName the name of the property
* @param oldValue the old value of the property
* @param newValue the new value for the property
*/
public void fireBindTargetChange(Component source, String propertyName, Object oldValue, Object newValue) {
if(listeners == null || listeners.size() == 0) {
return;
}
BindTarget[] array;
synchronized(this) {
array = new BindTarget[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (BindTarget)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(Display.getInstance().isEdt()) {
fireBindTargetChangeSync(array, source, propertyName, oldValue, newValue);
} else {
bindTargetArray = true;
Runnable cl = new CallbackClass(array, new Object[] {source, propertyName, oldValue, newValue});
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Fired when a property of the component changes to a new value
*
* @param source the source component
* @param propertyName the name of the property
* @param oldValue the old value of the property
* @param newValue the new value for the property
*/
private void fireBindTargetChangeSync(BindTarget[] arr, Component source, String propertyName, Object oldValue, Object newValue) {
int alen = arr.length;
for(int iter = 0 ; iter < alen ; iter++) {
arr[iter].propertyChanged(source, propertyName, oldValue, newValue);
}
}
/**
* Fires the style change even to the listeners
*
* @param property the property name for the event
* @param source the style firing the event
*/
public void fireStyleChangeEvent(String property, Style source) {
if(listeners == null || listeners.size() == 0) {
return;
}
// minor optimization for a common use case to avoid allocation costs
boolean isEdt = Display.getInstance().isEdt();
if(isEdt && listeners.size() == 1) {
StyleListener a = (StyleListener)listeners.get(0);
a.styleChanged(property, source);
return;
}
StyleListener[] array;
synchronized(this) {
array = new StyleListener[listeners.size()];
for(int iter = 0 ; iter < array.length ; iter++) {
array[iter] = (StyleListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireStyleChangeSync(array, property, source);
} else if (fireStyleEventsOnNonEDT) {
styleListenerArray = true;
Runnable cl = new CallbackClass(array, new Object[] {property, source});
Display.getInstance().callSerially(cl);
}
}
/**
* Synchronious internal call for common code
*/
private void fireDataChangeSync(DataChangedListener[] array, int type, int index) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].dataChanged(type, index);
}
}
/**
* Synchronious internal call for common code
*/
private void fireStyleChangeSync(StyleListener[] array, String property, Style source) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].styleChanged(property, source);
}
}
/**
* Synchronious internal call for common code
*/
private void fireSelectionSync(SelectionListener[] array, int oldSelection, int newSelection) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].selectionChanged(oldSelection, newSelection);
}
}
/**
* Synchronious internal call for common code
*/
private void fireScrollSync(ScrollListener[] array, int l, int t, int oldl, int oldt) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].scrollChanged(l, t, oldl, oldt);
}
}
/**
* Fires the event safely on the EDT without risk of concurrency errors
*
* @param ev the ActionEvent to fire to the listeners
*/
public void fireActionEvent(ActionEvent ev) {
if(listeners == null || listeners.size() == 0) {
return;
}
// minor optimization for a common use case to avoid allocation costs
boolean isEdt = Display.getInstance().isEdt();
if(isEdt && listeners.size() == 1) {
ActionListener a = (ActionListener)listeners.get(0);
a.actionPerformed(ev);
return;
}
ActionListener[] array;
synchronized(this) {
array = new ActionListener[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (ActionListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireActionSync(array, ev);
} else {
actionListenerArray = true;
Runnable cl = new CallbackClass(array, ev);
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Fires the event safely on the EDT without risk of concurrency errors
*
* @param oldSelection old selection
* @param newSelection new selection
*/
public void fireSelectionEvent(int oldSelection, int newSelection) {
if(listeners == null || listeners.size() == 0) {
return;
}
// minor optimization for a common use case to avoid allocation costs
boolean isEdt = Display.getInstance().isEdt();
if(isEdt && listeners.size() == 1) {
SelectionListener a = (SelectionListener)listeners.get(0);
a.selectionChanged(oldSelection, newSelection);
return;
}
SelectionListener[] array;
synchronized(this) {
array = new SelectionListener[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (SelectionListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireSelectionSync(array, oldSelection, newSelection);
} else {
selectionListenerArray = true;
Runnable cl = new CallbackClass(array, new int[] {oldSelection, newSelection});
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Fires the event safely on the EDT without risk of concurrency errors
*
*/
public void fireScrollEvent(int scrollX, int scrollY, int oldscrollX, int oldscrollY) {
if(listeners == null || listeners.size() == 0) {
return;
}
// minor optimization for a common use case to avoid allocation costs
boolean isEdt = Display.getInstance().isEdt();
if(isEdt && listeners.size() == 1) {
ScrollListener a = (ScrollListener)listeners.get(0);
a.scrollChanged(scrollX, scrollY, oldscrollX, oldscrollY);
return;
}
ScrollListener[] array;
synchronized(this) {
array = new ScrollListener[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (ScrollListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireScrollSync(array, scrollX, scrollY, oldscrollX, oldscrollY);
} else {
scrollListenerArray = true;
Runnable cl = new CallbackClass(array, new int[] {scrollX, scrollY, oldscrollX, oldscrollY});
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Synchronous internal call for common code
*/
private void fireActionSync(ActionListener[] array, ActionEvent ev) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
if(ev == null || !ev.isConsumed()) {
array[iter].actionPerformed(ev);
}
}
}
/**
* Fires the event safely on the EDT without risk of concurrency errors
*
* @param c the Component that gets the focus event
*/
public void fireFocus(Component c) {
if(listeners == null || listeners.size() == 0) {
return;
}
// minor optimization for a common use case to avoid allocation costs
boolean isEdt = Display.getInstance().isEdt();
if(isEdt && listeners.size() == 1) {
FocusListener a = (FocusListener)listeners.get(0);
if(c.hasFocus()) {
a.focusGained(c);
} else {
a.focusLost(c);
}
return;
}
FocusListener[] array;
synchronized(this) {
array = new FocusListener[listeners.size()];
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter] = (FocusListener)listeners.get(iter);
}
}
// if we already are on the EDT just fire the event
if(isEdt) {
fireFocusSync(array, c);
} else {
focusListenerArray = true;
Runnable cl = new CallbackClass(array, c);
if(blocking) {
Display.getInstance().callSeriallyAndWait(cl);
} else {
Display.getInstance().callSerially(cl);
}
}
}
/**
* Synchronous internal call for common code
*/
private void fireFocusSync(FocusListener[] array, Component c) {
if(c.hasFocus()) {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].focusGained(c);
}
} else {
int alen = array.length;
for(int iter = 0 ; iter < alen ; iter++) {
array[iter].focusLost(c);
}
}
}
/**
* Returns true if the event dispatcher has registered listeners
*
* @return true if the event dispatcher has registered listeners
*/
public boolean hasListeners() {
return listeners != null && listeners.size() > 0;
}
/**
* 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.
*
* @return the blocking state
*/
public boolean isBlocking() {
return 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.
*
* @param blocking the blocking value
*/
public void setBlocking(boolean blocking) {
this.blocking = blocking;
}
}