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      1 /*
      2  * Copyright (C) 2007 Esmertec AG.
      3  * Copyright (C) 2007 The Android Open Source Project
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *      http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 package com.android.mms.dom.events;
     19 
     20 import java.util.ArrayList;
     21 
     22 import org.w3c.dom.events.Event;
     23 import org.w3c.dom.events.EventException;
     24 import org.w3c.dom.events.EventListener;
     25 import org.w3c.dom.events.EventTarget;
     26 
     27 import android.util.Log;
     28 
     29 public class EventTargetImpl implements EventTarget {
     30     private static final String TAG = "EventTargetImpl";
     31     private ArrayList<EventListenerEntry> mListenerEntries;
     32     private EventTarget mNodeTarget;
     33 
     34     static class EventListenerEntry
     35     {
     36         final String mType;
     37         final EventListener mListener;
     38         final boolean mUseCapture;
     39 
     40         EventListenerEntry(String type, EventListener listener, boolean useCapture)
     41         {
     42             mType = type;
     43             mListener = listener;
     44             mUseCapture = useCapture;
     45         }
     46     }
     47 
     48     public EventTargetImpl(EventTarget target) {
     49         mNodeTarget = target;
     50     }
     51 
     52     public void addEventListener(String type, EventListener listener, boolean useCapture) {
     53         if ((type == null) || type.equals("") || (listener == null)) {
     54             return;
     55         }
     56 
     57         // Make sure we have only one entry
     58         removeEventListener(type, listener, useCapture);
     59 
     60         if (mListenerEntries == null) {
     61             mListenerEntries = new ArrayList<EventListenerEntry>();
     62         }
     63         mListenerEntries.add(new EventListenerEntry(type, listener, useCapture));
     64     }
     65 
     66     public boolean dispatchEvent(Event evt) throws EventException {
     67         // We need to use the internal APIs to modify and access the event status
     68         EventImpl eventImpl = (EventImpl)evt;
     69 
     70         if (!eventImpl.isInitialized()) {
     71             throw new EventException(EventException.UNSPECIFIED_EVENT_TYPE_ERR,
     72                     "Event not initialized");
     73         } else if ((eventImpl.getType() == null) || eventImpl.getType().equals("")) {
     74             throw new EventException(EventException.UNSPECIFIED_EVENT_TYPE_ERR,
     75                     "Unspecified even type");
     76         }
     77 
     78         // Initialize event status
     79         eventImpl.setTarget(mNodeTarget);
     80 
     81         // TODO: At this point, to support event capturing and bubbling, we should
     82         // establish the chain of EventTargets from the top of the tree to this
     83         // event's target.
     84 
     85         // TODO: CAPTURING_PHASE skipped
     86 
     87         // Handle AT_TARGET
     88         // Invoke handleEvent of non-capturing listeners on this EventTarget.
     89         eventImpl.setEventPhase(Event.AT_TARGET);
     90         eventImpl.setCurrentTarget(mNodeTarget);
     91         if (!eventImpl.isPropogationStopped() && (mListenerEntries != null)) {
     92             for (int i = 0; i < mListenerEntries.size(); i++) {
     93                 EventListenerEntry listenerEntry = mListenerEntries.get(i);
     94                 if (!listenerEntry.mUseCapture
     95                         && listenerEntry.mType.equals(eventImpl.getType())) {
     96                     try {
     97                         listenerEntry.mListener.handleEvent(eventImpl);
     98                     }
     99                     catch (Exception e) {
    100                         // Any exceptions thrown inside an EventListener will
    101                         // not stop propagation of the event
    102                         Log.w(TAG, "Catched EventListener exception", e);
    103                     }
    104                 }
    105             }
    106         }
    107 
    108         if (eventImpl.getBubbles()) {
    109             // TODO: BUBBLING_PHASE skipped
    110         }
    111 
    112         return eventImpl.isPreventDefault();
    113     }
    114 
    115     public void removeEventListener(String type, EventListener listener,
    116             boolean useCapture) {
    117         if (null == mListenerEntries) {
    118             return;
    119         }
    120         for (int i = 0; i < mListenerEntries.size(); i ++) {
    121             EventListenerEntry listenerEntry = mListenerEntries.get(i);
    122             if ((listenerEntry.mUseCapture == useCapture)
    123                     && (listenerEntry.mListener == listener)
    124                     && listenerEntry.mType.equals(type)) {
    125                 mListenerEntries.remove(i);
    126                 break;
    127             }
    128         }
    129     }
    130 
    131 }
    132