formview.java

java jdk 1.4的源码

            break;
        }
        return super.getMaximumSpan(axis);
    }


    /**
     * Responsible for processeing the ActionEvent.
     * If the element associated with the FormView,
     * has a type of "submit", "reset", "text" or "password" 
     * then the action is processed.  In the case of a "submit" 
     * the form is submitted.  In the case of a "reset"
     * the form is reset to its original state.
     * In the case of "text" or "password", if the 
     * element is the last one of type "text" or "password",
     * the form is submitted.  Otherwise, focus is transferred
     * to the next component in the form.
     *
     * @param evt the ActionEvent.
     */
    public void actionPerformed(ActionEvent evt) {
	Element element = getElement();
	StringBuffer dataBuffer = new StringBuffer();
	HTMLDocument doc = (HTMLDocument)getDocument();
	AttributeSet attr = element.getAttributes();
	
	String type = (String) attr.getAttribute(HTML.Attribute.TYPE);

	if (type.equals("submit")) { 
	    getFormData(dataBuffer);
	    submitData(dataBuffer.toString());
	} else if (type.equals("reset")) {
	    resetForm();
	} else if (type.equals("text") || type.equals("password")) {
	    if (isLastTextOrPasswordField()) {
		getFormData(dataBuffer);
		submitData(dataBuffer.toString());
	    } else {
		getComponent().transferFocus();
	    }
	}
    }


    /**
     * This method is responsible for submitting the form data.
     * A thread is forked to undertake the submission.
     */
    protected void submitData(String data) {
	//System.err.println("data ->"+data+"<-");
	SubmitThread dataThread = new SubmitThread(getElement(), data);
	dataThread.start();
    }


    /**
     * The SubmitThread is responsible for submitting the form.
     * It performs a POST or GET based on the value of method
     * attribute associated with  HTML.Tag.FORM.  In addition to
     * submitting, it is also responsible for display the 
     * results of the form submission.
     */
    class SubmitThread extends Thread {

	String data;
	HTMLDocument hdoc;
	HTMLDocument newDoc;
	AttributeSet formAttr;
	InputStream in;
	
	public SubmitThread(Element elem, String data) {
	    this.data = data;
	    hdoc = (HTMLDocument)elem.getDocument();
            Element formE = getFormElement();
            if (formE != null) {
                formAttr = formE.getAttributes();
            }
	}


	/**
	 * This method is responsible for extracting the
	 * method and action attributes associated with the
	 * &lt;FORM&gt; and using those to determine how (POST or GET)
	 * and where (URL) to submit the form.  If action is
	 * not specified, the base url of the existing document is
	 * used.  Also, if method is not specified, the default is
	 * GET.  Once form submission is done, run uses the
	 * SwingUtilities.invokeLater() method, to load the results
	 * of the form submission into the current JEditorPane.
	 */
	public void run() {

	    if (data.length() > 0) {

		String method = getMethod();
		String action = getAction();
		
		URL url;
		try {
		    URL actionURL;

		    /* if action is null use the base url and ensure that
		       the file name excludes any parameters that may be attached */
		    URL baseURL = hdoc.getBase();
		    if (action == null) {
			
			String file = baseURL.getFile();
			actionURL = new URL(baseURL.getProtocol(), 
					    baseURL.getHost(), 
					    baseURL.getPort(), 
					    file);
		    } else {
			actionURL = new URL(baseURL, action);
		    }

		    URLConnection connection;


		    if ("post".equals(method)) {
			url = actionURL;
			connection = url.openConnection();
			postData(connection, data);
		    } else {
			/* the default, GET */
			url = new URL(actionURL+"?"+data);
			connection = url.openConnection();
		    }
		    in = connection.getInputStream();

		    // safe assumption since we are in an html document
		    JEditorPane c = (JEditorPane)getContainer();
		    HTMLEditorKit kit = (HTMLEditorKit)c.getEditorKit();
		    newDoc = (HTMLDocument)kit.createDefaultDocument();
		    newDoc.putProperty(Document.StreamDescriptionProperty, url);

		    
		    Runnable callLoadDocument = new Runnable() {
			public void run() {
			    loadDocument();
			}
		    };
		    SwingUtilities.invokeLater(callLoadDocument);
		} catch (MalformedURLException m) {
		    // REMIND how do we deal with exceptions ??
		} catch (IOException e) {
		    // REMIND how do we deal with exceptions ??
		}
	    }
	}


	/**
	 * This method is responsible for loading the
	 * document into the FormView's container,
	 * which is a JEditorPane.
	 */
	public void loadDocument() {
	    JEditorPane c = (JEditorPane)getContainer();
	    try {
		c.read(in, newDoc);
	    } catch (IOException e) {
		// REMIND failed to load document
	    }
	}

	/**
	 * Get the value of the action attribute.
	 */
	public String getAction() {
	    if (formAttr == null) { 
		return null;
	    }
	    return (String)formAttr.getAttribute(HTML.Attribute.ACTION);
	}
	
	/**
	 * Get the form's method parameter.
	 */
	String getMethod() {
	    if (formAttr != null) {
		String method = (String)formAttr.getAttribute(HTML.Attribute.METHOD);
		if (method != null) {
		    return method.toLowerCase();
		}
	    }
	    return null;
	} 


	/**
	 * This method is responsible for writing out the form submission
	 * data when the method is POST.
	 * 
	 * @param connection to use.
	 * @param data to write.
	 */
	public void postData(URLConnection connection, String data) {
	    connection.setDoOutput(true);
 	    PrintWriter out = null;
	    try {
		out = new PrintWriter(new OutputStreamWriter(connection.getOutputStream()));
		out.print(data);
		out.flush();
	    } catch (IOException e) {
		// REMIND: should do something reasonable!
	    } finally {
		if (out != null) {
		    out.close();
		}
	    }
	}
    }

    /**
     * MouseEventListener class to handle form submissions when
     * an input with type equal to image is clicked on.
     * A MouseListener is necessary since along with the image
     * data the coordinates associated with the mouse click
     * need to be submitted.
     */
    protected class MouseEventListener extends MouseAdapter {

	public void mouseReleased(MouseEvent evt) {
	    String imageData = getImageData(evt.getPoint());
	    imageSubmit(imageData);
	}
    }

    /**
     * This method is called to submit a form in response
     * to a click on an image -- an &lt;INPUT&gt; form
     * element of type "image".
     *
     * @param imageData the mouse click coordinates.
     */
    protected void imageSubmit(String imageData) {

	StringBuffer dataBuffer = new StringBuffer();
	Element elem = getElement();
	HTMLDocument hdoc = (HTMLDocument)elem.getDocument();
	getFormData(dataBuffer);
	if (dataBuffer.length() > 0) {
	    dataBuffer.append('&');
	}
	dataBuffer.append(imageData);
	submitData(dataBuffer.toString());
	return;
    }

    /**
     * Extracts the value of the name attribute
     * associated with the input element of type
     * image.  If name is defined it is encoded using
     * the URLEncoder.encode() method and the 
     * image data is returned in the following format:
     *	    name + ".x" +"="+ x +"&"+ name +".y"+"="+ y
     * otherwise,
     * 	    "x="+ x +"&y="+ y
     * 
     * @param point associated with the mouse click.
     * @return the image data.
     */
    private String getImageData(Point point) {
	    
	String mouseCoords = point.x + ":" + point.y;
	int sep = mouseCoords.indexOf(':');
	String x = mouseCoords.substring(0, sep);
	String y = mouseCoords.substring(++sep);
	String name = (String) getElement().getAttributes().getAttribute(HTML.Attribute.NAME);
	
	String data;
	if (name == null || name.equals("")) {
	    data = "x="+ x +"&y="+ y;
	} else {
	    name = URLEncoder.encode(name);
	    data = name + ".x" +"="+ x +"&"+ name +".y"+"="+ y;
	}
	return data;
    }


    /**
     * The following methods provide functionality required to
     * iterate over a the elements of the form and in the case
     * of a form submission, extract the data from each model
     * that is associated with each form element, and in the
     * case of reset, reinitialize the each model to its
     * initial state.
     */


    /**
     * Returns the Element representing the <code>FORM</code>.
     */
    private Element getFormElement() {
        Element elem = getElement();
        while (elem != null) {
            if (elem.getAttributes().getAttribute
                (StyleConstants.NameAttribute) == HTML.Tag.FORM) {
                return elem;
            }
            elem = elem.getParentElement();
        }
        return null;
    }

    /**
     * Iterates over the 
     * element hierarchy, extracting data from the 
     * models associated with the relevant form elements.
     * "Relevant" means the form elements that are part
     * of the same form whose element triggered the submit
     * action.
     *
     * @param buffer        the buffer that contains that data to submit
     * @param targetElement the element that triggered the 
     *                      form submission
     */
    void getFormData(StringBuffer buffer) {
        Element formE = getFormElement();
        if (formE != null) {
            ElementIterator it = new ElementIterator(formE);
            Element next;

            while ((next = it.next()) != null) {
                if (isControl(next)) {
                    String type = (String)next.getAttributes().getAttribute
                                       (HTML.Attribute.TYPE);

                    if (type != null && type.equals("submit") &&