htmldocument.java

Mobile 应用程序使用 Java Micro Edition (Java ME) 平台

     * Creates a document leaf element that directly represents
     * text (doesn't have any children).  This is implemented
     * to return an element of type 
     * <code>HTMLDocument.RunElement</code>.
     *
     * @param parent the parent element
     * @param a the attributes for the element
     * @param p0 the beginning of the range (must be at least 0)
     * @param p1 the end of the range (must be at least p0)
     * @return the new element
     */
    protected Element createLeafElement(Element parent, AttributeSet a, int p0, int p1) {
	return new RunElement(parent, a, p0, p1);
    }

    /**
     * Creates a document branch element, that can contain other elements.
     * This is implemented to return an element of type 
     * <code>HTMLDocument.BlockElement</code>.
     *
     * @param parent the parent element
     * @param a the attributes
     * @return the element
     */
    protected Element createBranchElement(Element parent, AttributeSet a) {
	return new BlockElement(parent, a);
    }

    /**
     * Creates the root element to be used to represent the
     * default document structure.
     *
     * @return the element base
     */
    protected AbstractElement createDefaultRoot() {
	// grabs a write-lock for this initialization and
	// abandon it during initialization so in normal
	// operation we can detect an illegitimate attempt
	// to mutate attributes.
	writeLock();
	MutableAttributeSet a = new SimpleAttributeSet();
	a.addAttribute(StyleConstants.NameAttribute, HTML.Tag.HTML);
	BlockElement html = new BlockElement(null, a.copyAttributes());
	a.removeAttributes(a);
	a.addAttribute(StyleConstants.NameAttribute, HTML.Tag.BODY);
	BlockElement body = new BlockElement(html, a.copyAttributes());
	a.removeAttributes(a);
	a.addAttribute(StyleConstants.NameAttribute, HTML.Tag.P);
        getStyleSheet().addCSSAttributeFromHTML(a, CSS.Attribute.MARGIN_TOP, "0");
	BlockElement paragraph = new BlockElement(body, a.copyAttributes());
	a.removeAttributes(a);
	a.addAttribute(StyleConstants.NameAttribute, HTML.Tag.CONTENT);
	RunElement brk = new RunElement(paragraph, a, 0, 1);
	Element[] buff = new Element[1];
	buff[0] = brk;
	paragraph.replace(0, 0, buff);
	buff[0] = paragraph;
	body.replace(0, 0, buff);
	buff[0] = body;
	html.replace(0, 0, buff);
	writeUnlock();
	return html;
    }

    /**
     * Sets the number of tokens to buffer before trying to update
     * the documents element structure.
     *
     * @param n  the number of tokens to buffer
     */
    public void setTokenThreshold(int n) {
	putProperty(TokenThreshold, new Integer(n));
    }

    /**
     * Gets the number of tokens to buffer before trying to update
     * the documents element structure.  The default value is
     * <code>Integer.MAX_VALUE</code>.
     *
     * @return the number of tokens to buffer
     */
    public int getTokenThreshold() {
	Integer i = (Integer) getProperty(TokenThreshold);
	if (i != null) {
	    return i.intValue();
	}
	return Integer.MAX_VALUE;
    }

    /**
     * Determines how unknown tags are handled by the parser.
     * If set to true, unknown
     * tags are put in the model, otherwise they are dropped.
     *
     * @param preservesTags  true if unknown tags should be
     *		saved in the model, otherwise tags are dropped
     * @see javax.swing.text.html.HTML.Tag
     */
    public void setPreservesUnknownTags(boolean preservesTags) {
	preservesUnknownTags = preservesTags;
    }

    /**
     * Returns the behavior the parser observes when encountering
     * unknown tags.
     *
     * @see javax.swing.text.html.HTML.Tag
     * @return true if unknown tags are to be preserved when parsing
     */
    public boolean getPreservesUnknownTags() {
	return preservesUnknownTags;
    }

    /**
     * Processes <code>HyperlinkEvents</code> that
     * are generated by documents in an HTML frame. 
     * The <code>HyperlinkEvent</code> type, as the parameter suggests,
     * is <code>HTMLFrameHyperlinkEvent</code>.
     * In addition to the typical information contained in a
     * <code>HyperlinkEvent</code>,
     * this event contains the element that corresponds to the frame in
     * which the click happened (the source element) and the
     * target name.  The target name has 4 possible values:
     * <ul>
     * <li>  _self
     * <li>  _parent
     * <li>  _top
     * <li>  a named frame
     * </ul>
     *
     * If target is _self, the action is to change the value of the
     * <code>HTML.Attribute.SRC</code> attribute and fires a
     * <code>ChangedUpdate</code> event.
     *<p>
     * If the target is _parent, then it deletes the parent element,
     * which is a &lt;FRAMESET&gt; element, and inserts a new &lt;FRAME&gt;
     * element, and sets its <code>HTML.Attribute.SRC</code> attribute
     * to have a value equal to the destination URL and fire a
     * <code>RemovedUpdate</code> and <code>InsertUpdate</code>.
     *<p>
     * If the target is _top, this method does nothing. In the implementation
     * of the view for a frame, namely the <code>FrameView</code>,
     * the processing of _top is handled.  Given that _top implies
     * replacing the entire document, it made sense to handle this outside
     * of the document that it will replace.
     *<p>
     * If the target is a named frame, then the element hierarchy is searched
     * for an element with a name equal to the target, its
     * <code>HTML.Attribute.SRC</code> attribute is updated and a
     * <code>ChangedUpdate</code> event is fired.
     *
     * @param e the event
     */
    public void processHTMLFrameHyperlinkEvent(HTMLFrameHyperlinkEvent e) {
 	String frameName = e.getTarget();
	Element element = e.getSourceElement();
	String urlStr = e.getURL().toString();

	if (frameName.equals("_self")) {
	    /*
	      The source and destination elements
	      are the same.
	    */
	    updateFrame(element, urlStr);
	} else if (frameName.equals("_parent")) {
	    /*
	      The destination is the parent of the frame.
	    */
	    updateFrameSet(element.getParentElement(), urlStr);
	} else {
	    /*
	      locate a named frame
	    */
	    Element targetElement = findFrame(frameName);
	    if (targetElement != null) {
		updateFrame(targetElement, urlStr);
	    }
	}
    }

    
    /**
     * Searches the element hierarchy for an FRAME element
     * that has its name attribute equal to the <code>frameName</code>.
     *
     * @param frameName
     * @return the element whose NAME attribute has a value of
     *          <code>frameName</code>; returns <code>null</code>
     *		if not found
     */
    private Element findFrame(String frameName) {
	ElementIterator it = new ElementIterator(this);
	Element next = null;

	while ((next = it.next()) != null) {
	    AttributeSet attr = next.getAttributes();
	    if (matchNameAttribute(attr, HTML.Tag.FRAME)) {
		String frameTarget = (String)attr.getAttribute(HTML.Attribute.NAME);
		if (frameTarget != null && frameTarget.equals(frameName)) {
		    break;
		}
	    }
	}
	return next;
    }

    /**
     * Returns true if <code>StyleConstants.NameAttribute</code> is
     * equal to the tag that is passed in as a parameter.
     *
     * @param attr the attributes to be matched
     * @param tag the value to be matched
     * @return true if there is a match, false otherwise
     * @see javax.swing.text.html.HTML.Attribute
     */
    static boolean matchNameAttribute(AttributeSet attr, HTML.Tag tag) {
	Object o = attr.getAttribute(StyleConstants.NameAttribute);
	if (o instanceof HTML.Tag) {
	    HTML.Tag name = (HTML.Tag) o;
	    if (name == tag) {
		return true;
	    }
	}
	return false;
    }

    /**
     * Replaces a frameset branch Element with a frame leaf element.
     *
     * @param element the frameset element to remove
     * @param url     the value for the SRC attribute for the
     *                new frame that will replace the frameset
     */
    private void updateFrameSet(Element element, String url) {
	try {
	    int startOffset = element.getStartOffset();
	    int endOffset = Math.min(getLength(), element.getEndOffset());
            String html = "<frame";
            if (url != null) {
                html += " src=\"" + url + "\"";
            }
            html += ">";
            installParserIfNecessary();
            setOuterHTML(element, html);
	} catch (BadLocationException e1) {
	    // Should handle this better
	} catch (IOException ioe) {
	    // Should handle this better
	}
    }


    /**
     * Updates the Frame elements <code>HTML.Attribute.SRC attribute</code>
     * and fires a <code>ChangedUpdate</code> event.
     *
     * @param element a FRAME element whose SRC attribute will be updated
     * @param url     a string specifying the new value for the SRC attribute
     */
    private void updateFrame(Element element, String url) {

	try {
	    writeLock();
	    DefaultDocumentEvent changes = new DefaultDocumentEvent(element.getStartOffset(),
								    1,
								    DocumentEvent.EventType.CHANGE);
	    AttributeSet sCopy = element.getAttributes().copyAttributes();
	    MutableAttributeSet attr = (MutableAttributeSet) element.getAttributes();
	    changes.addEdit(new AttributeUndoableEdit(element, sCopy, false));
	    attr.removeAttribute(HTML.Attribute.SRC);
	    attr.addAttribute(HTML.Attribute.SRC, url);
	    changes.end();
	    fireChangedUpdate(changes);
	    fireUndoableEditUpdate(new UndoableEditEvent(this, changes));
	} finally {
	    writeUnlock();
	}
    }


    /**
     * Returns true if the document will be viewed in a frame.
     * @return true if document will be viewed in a frame, otherwise false
     */
    boolean isFrameDocument() {
	return frameDocument;
    }
    
    /**
     * Sets a boolean state about whether the document will be
     * viewed in a frame.
     * @param frameDoc  true if the document will be viewed in a frame,
     *		otherwise false
     */
    void setFrameDocumentState(boolean frameDoc) {
 	this.frameDocument = frameDoc;
    }

    /**
     * Adds the specified map, this will remove a Map that has been
     * previously registered with the same name.
     *
     * @param map  the <code>Map</code> to be registered
     */
    void addMap(Map map) {
	String     name = map.getName();

	if (name != null) {
	    Object     maps = getProperty(MAP_PROPERTY);

	    if (maps == null) {
		maps = new Hashtable(11);
		putProperty(MAP_PROPERTY, maps);
	    }
	    if (maps instanceof Hashtable) {
		((Hashtable)maps).put("#" + name, map);
	    }
	}
    }

    /**
     * Removes a previously registered map.
     * @param map the <code>Map</code> to be removed
     */
    void removeMap(Map map) {
	String     name = map.getName();

	if (name != null) {
	    Object     maps = getProperty(MAP_PROPERTY);

	    if (maps instanceof Hashtable) {
		((Hashtable)maps).remove("#" + name);
	    }
	}
    }

    /**
     * Returns the Map associated with the given name.
     * @param the name of the desired <code>Map</code>
     * @return the <code>Map</code> or <code>null</code> if it can't
     *		be found, or if <code>name</code> is <code>null</code>
     */
    Map getMap(String name) {
	if (name != null) {
	    Object     maps = getProperty(MAP_PROPERTY);

	    if (maps != null && (maps instanceof Hashtable)) {
		return (Map)((Hashtable)maps).get(name);
	    }
	}
	return null;
    }

    /**
     * Returns an <code>Enumeration</code> of the possible Maps.
     * @return the enumerated list of maps, or <code>null</code>
     *		if the maps are not an instance of <code>Hashtable</code>
     */
    Enumeration getMaps() {
	Object     maps = getProperty(MAP_PROPERTY);

	if (maps instanceof Hashtable) {
	    return ((Hashtable)maps).elements();
	}