documentimpl.java

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            int size = ranges.size();
            for (int i = 0; i != size; i++) {
                ((RangeImpl)ranges.elementAt(i)).receiveReplacedText(node);
            }
        }
    }

    /**
     * A method to be called when some text was deleted from a text node,
     * so that live objects can be notified.
     */
    void deletedText(NodeImpl node, int offset, int count) {
        // notify ranges
        if (ranges != null) {
            int size = ranges.size();
            for (int i = 0; i != size; i++) {
                ((RangeImpl)ranges.elementAt(i)).receiveDeletedText(node,
                                                                offset, count);
            }
        }
    }

    /**
     * A method to be called when some text was inserted into a text node,
     * so that live objects can be notified.
     */
    void insertedText(NodeImpl node, int offset, int count) {
        // notify ranges
        if (ranges != null) {
            int size = ranges.size();
            for (int i = 0; i != size; i++) {
                ((RangeImpl)ranges.elementAt(i)).receiveInsertedText(node,
                                                                offset, count);
            }
        }
    }

    /**
     * A method to be called when a text node has been split,
     * so that live objects can be notified.
     */
    void splitData(Node node, Node newNode, int offset) {
        // notify ranges
        if (ranges != null) {
            int size = ranges.size();
            for (int i = 0; i != size; i++) {
                ((RangeImpl)ranges.elementAt(i)).receiveSplitData(node,
                                                              newNode, offset);
            }
        }
    }

    //
    // DocumentEvent methods
    //

    /**
     * Introduced in DOM Level 2. Optional. <p>
     * Create and return Event objects.
     *
     * @param type The eventType parameter specifies the type of Event
     * interface to be created.  If the Event interface specified is supported
     * by the implementation this method will return a new Event of the
     * interface type requested. If the Event is to be dispatched via the
     * dispatchEvent method the appropriate event init method must be called
     * after creation in order to initialize the Event's values.  As an
     * example, a user wishing to synthesize some kind of Event would call
     * createEvent with the parameter "Events". The initEvent method could then
     * be called on the newly created Event to set the specific type of Event
     * to be dispatched and set its context information.
     * @return Newly created Event
     * @exception DOMException NOT_SUPPORTED_ERR: Raised if the implementation
     * does not support the type of Event interface requested
     * @since WD-DOM-Level-2-19990923
     */
    public Event createEvent(String type)
	throws DOMException {
	    if (type.equalsIgnoreCase("Events") || "Event".equals(type))
	        return new EventImpl();
	    if (type.equalsIgnoreCase("MutationEvents") ||
                "MutationEvent".equals(type))
	        return new MutationEventImpl();
	    else {
            String msg = DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "NOT_SUPPORTED_ERR", null);
	        throw new DOMException(DOMException.NOT_SUPPORTED_ERR, msg);
        }
	}

    /**
     * Sets whether the DOM implementation generates mutation events
     * upon operations.
     */
    void setMutationEvents(boolean set) {
        mutationEvents = set;
    }

    /**
     * Returns true if the DOM implementation generates mutation events.
     */
    boolean getMutationEvents() {
        return mutationEvents;
    }

    /**
     * Store event listener registered on a given node
     * This is another place where we could use weak references! Indeed, the
     * node here won't be GC'ed as long as some listener is registered on it,
     * since the eventsListeners table will have a reference to the node.
     */
    protected void setEventListeners(NodeImpl n, Vector listeners) {
        if (eventListeners == null) {
            eventListeners = new Hashtable();
        }
        if (listeners == null) {
            eventListeners.remove(n);
            if (eventListeners.isEmpty()) {
                // stop firing events when there isn't any listener
                mutationEvents = false;
            }
        } else {
            eventListeners.put(n, listeners);
            // turn mutation events on
            mutationEvents = true;
        }
    }

    /**
     * Retreive event listener registered on a given node
     */
    protected Vector getEventListeners(NodeImpl n) {
        if (eventListeners == null) {
            return null;
        }
        return (Vector) eventListeners.get(n);
    }

    //
    // EventTarget support (public and internal)
    //

    //
    // Constants
    //

    /*
     * NON-DOM INTERNAL: Class LEntry is just a struct used to represent
     * event listeners registered with this node. Copies of this object
     * are hung from the nodeListeners Vector.
     * <p>
     * I considered using two vectors -- one for capture,
     * one for bubble -- but decided that since the list of listeners 
     * is probably short in most cases, it might not be worth spending
     * the space. ***** REVISIT WHEN WE HAVE MORE EXPERIENCE.
     */
    class LEntry implements Serializable {

        private static final long serialVersionUID = 3258416144514626360L;
        String type;
        EventListener listener;
        boolean useCapture;
	    
        /** NON-DOM INTERNAL: Constructor for Listener list Entry 
         * @param type Event name (NOT event group!) to listen for.
         * @param listener Who gets called when event is dispatched
         * @param useCaptue True iff listener is registered on
         *  capturing phase rather than at-target or bubbling
         */
        LEntry(String type, EventListener listener, boolean useCapture)
        {
            this.type = type;
            this.listener = listener;
            this.useCapture = useCapture;
        }

    } // LEntry
	
    /**
     * Introduced in DOM Level 2. <p> Register an event listener with this
     * Node. A listener may be independently registered as both Capturing and
     * Bubbling, but may only be registered once per role; redundant
     * registrations are ignored.
     * @param node node to add listener to
     * @param type Event name (NOT event group!) to listen for.
     * @param listener Who gets called when event is dispatched
     * @param useCapture True iff listener is registered on
     *  capturing phase rather than at-target or bubbling
     */
    protected void addEventListener(NodeImpl node, String type,
                                    EventListener listener, boolean useCapture)
    {
        // We can't dispatch to blank type-name, and of course we need
        // a listener to dispatch to
        if (type == null || type.equals("") || listener == null)
            return;
      
        // Each listener may be registered only once per type per phase.
        // Simplest way to code that is to zap the previous entry, if any.
        removeEventListener(node, type, listener, useCapture);
	    
        Vector nodeListeners = getEventListeners(node);
        if(nodeListeners == null) {
            nodeListeners = new Vector();
            setEventListeners(node, nodeListeners);
        }
        nodeListeners.addElement(new LEntry(type, listener, useCapture));
	    
        // Record active listener
        LCount lc = LCount.lookup(type);
        if (useCapture) {
            ++lc.captures;
            ++lc.total;
        }
        else {
            ++lc.bubbles;
            ++lc.total;
        }

    } // addEventListener(NodeImpl,String,EventListener,boolean) :void
	
    /**
     * Introduced in DOM Level 2. <p> Deregister an event listener previously
     * registered with this Node.  A listener must be independently removed
     * from the Capturing and Bubbling roles. Redundant removals (of listeners
     * not currently registered for this role) are ignored.
     * @param node node to remove listener from
     * @param type Event name (NOT event group!) to listen for.
     * @param listener Who gets called when event is dispatched
     * @param useCapture True iff listener is registered on
     *  capturing phase rather than at-target or bubbling
     */
    protected void removeEventListener(NodeImpl node, String type,
                                       EventListener listener,
                                       boolean useCapture)
    {
        // If this couldn't be a valid listener registration, ignore request
        if (type == null || type.equals("") || listener == null)
            return;
        Vector nodeListeners = getEventListeners(node);
        if (nodeListeners == null)
            return;

        // Note that addListener has previously ensured that 
        // each listener may be registered only once per type per phase.
        // count-down is OK for deletions!
        for (int i = nodeListeners.size() - 1; i >= 0; --i) {
            LEntry le = (LEntry) nodeListeners.elementAt(i);
            if (le.useCapture == useCapture && le.listener == listener && 
                le.type.equals(type)) {
                nodeListeners.removeElementAt(i);
                // Storage management: Discard empty listener lists
                if (nodeListeners.size() == 0)
                    setEventListeners(node, null);

                // Remove active listener
                LCount lc = LCount.lookup(type);
                if (useCapture) {
                    --lc.captures;
                    --lc.total;
                }
                else {
                    --lc.bubbles;
                    --lc.total;
                }

                break;  // Found it; no need to loop farther.
            }
        }
    } // removeEventListener(NodeImpl,String,EventListener,boolean) :void

    protected void copyEventListeners(NodeImpl src, NodeImpl tgt) {
        Vector nodeListeners = getEventListeners(src);
	if (nodeListeners == null) {
	    return;
	}
	setEventListeners(tgt, (Vector) nodeListeners.clone());
    }

    /**
     * Introduced in DOM Level 2. <p>
     * Distribution engine for DOM Level 2 Events. 
     * <p>
     * Event propagation runs as follows:
     * <ol>
     * <li>Event is dispatched to a particular target node, which invokes
     *   this code. Note that the event's stopPropagation flag is
     *   cleared when dispatch begins; thereafter, if it has 
     *   been set before processing of a node commences, we instead
     *   immediately advance to the DEFAULT phase.
     * <li>The node's ancestors are established as destinations for events.
     *   For capture and bubble purposes, node ancestry is determined at 
     *   the time dispatch starts. If an event handler alters the document 
     *   tree, that does not change which nodes will be informed of the event. 
     * <li>CAPTURING_PHASE: Ancestors are scanned, root to target, for 
     *   Capturing listeners. If found, they are invoked (see below). 
     * <li>AT_TARGET: 
     *   Event is dispatched to NON-CAPTURING listeners on the
     *   target node. Note that capturing listeners on this node are _not_
     *   invoked.
     * <li>BUBBLING_PHASE: Ancestors are scanned, target to root, for
     *   non-capturing listeners. 
     * <li>Default processing: Some DOMs have default behaviors bound to
     *   specific nodes. If this DOM does, and if the event's preventDefault
     *   flag has not been set, we now return to the target node and process
     *   its default handler for this event, if any.
     * </ol>
     * <p>
     * Note that registration of handlers during processing of an event does
     * not take effect during this phase of this event; they will not be called
     * until the next time this node is visited by dispatchEvent. On the other
     * hand, removals take effect immediately.
     * <p>
     * If an event handler itself causes events to be dispatched, they are
     * processed synchronously, before processing resumes
     * on the event which triggered them. Please be aware that this may 
     * result in events arriving at listeners "out of order" relative
     * to the actual sequence of requests.
     * <p>
     * Note that our implementation resets the event's stop/prevent flags
     * when dispatch begins.
     * I believe the DOM's intent is that event objects be redispatchable,
     * though it isn't stated in those terms.
     * @param node node to dispatch to
     * @param event the event object to be dispatched to 
     *              registered EventListeners
     * @return true if the event's <code>preventDefault()</code>
     *              method was invoked by an EventListener; otherwise false.