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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package javax.swing.text.html;

import java.net.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;

Component decorator that implements the view interface
for form elements, <input>, <textarea>,
and <select>.  The model for the component is stored
as an attribute of the element (using StyleConstants.ModelAttribute),
and is used to build the component of the view.  The type
of the model is assumed to of the type that would be set by
HTMLDocument.HTMLReader.FormAction.  If there are
multiple views mapped over the document, they will share the
embedded component models.

The following table shows what components get built
by this view.

Shows what components get built by this view

  

    
Element Type
    
Component built


  

    
input, type button
    
JButton
  

    
input, type checkbox
    
JCheckBox
  

    
input, type image
    
JButton
  

    
input, type password
    
JPasswordField
  

    
input, type radio
    
JRadioButton
  

    
input, type reset
    
JButton
  

    
input, type submit
    
JButton
  

    
input, type text
    
JTextField
  

    
select, size > 1 or multiple attribute defined
    
JList in a JScrollPane
  

    
select, size unspecified or 1
    
JComboBox
  

    
textarea
    
JTextArea in a JScrollPane
  

    
input, type file
    
JTextField


Author:
Timothy Prinzing, Sunita Mani/**
 * Component decorator that implements the view interface
 * for form elements, &lt;input&gt;, &lt;textarea&gt;,
 * and &lt;select&gt;.  The model for the component is stored
 * as an attribute of the element (using StyleConstants.ModelAttribute),
 * and is used to build the component of the view.  The type
 * of the model is assumed to of the type that would be set by
 * <code>HTMLDocument.HTMLReader.FormAction</code>.  If there are
 * multiple views mapped over the document, they will share the
 * embedded component models.
 * <p>
 * The following table shows what components get built
 * by this view.
 *
 * <table class="striped">
 * <caption>Shows what components get built by this view</caption>
 * <thead>
 *   <tr>
 *     <th scope="col">Element Type
 *     <th scope="col">Component built
 * </thead>
 * <tbody>
 *   <tr>
 *     <th scope="row">input, type button
 *     <td>JButton
 *   <tr>
 *     <th scope="row">input, type checkbox
 *     <td>JCheckBox
 *   <tr>
 *     <th scope="row">input, type image
 *     <td>JButton
 *   <tr>
 *     <th scope="row">input, type password
 *     <td>JPasswordField
 *   <tr>
 *     <th scope="row">input, type radio
 *     <td>JRadioButton
 *   <tr>
 *     <th scope="row">input, type reset
 *     <td>JButton
 *   <tr>
 *     <th scope="row">input, type submit
 *     <td>JButton
 *   <tr>
 *     <th scope="row">input, type text
 *     <td>JTextField
 *   <tr>
 *     <th scope="row">select, size &gt; 1 or multiple attribute defined
 *     <td>JList in a JScrollPane
 *   <tr>
 *     <th scope="row">select, size unspecified or 1
 *     <td>JComboBox
 *   <tr>
 *     <th scope="row">textarea
 *     <td>JTextArea in a JScrollPane
 *   <tr>
 *     <th scope="row">input, type file
 *     <td>JTextField
 * </tbody>
 * </table>
 *
 * @author Timothy Prinzing
 * @author Sunita Mani
 */
public class FormView extends ComponentView implements ActionListener {

    
If a value attribute is not specified for a FORM input element
of type "submit", then this default string is used.
Deprecated:
As of 1.3, value now comes from UIManager property
            FormView.submitButtonText/**
     * If a value attribute is not specified for a FORM input element
     * of type "submit", then this default string is used.
     *
     * @deprecated As of 1.3, value now comes from UIManager property
     *             FormView.submitButtonText
     */
    @Deprecated
    public static final String SUBMIT = new String("Submit Query");
    
If a value attribute is not specified for a FORM input element
of type "reset", then this default string is used.
Deprecated:
As of 1.3, value comes from UIManager UIManager property
            FormView.resetButtonText/**
     * If a value attribute is not specified for a FORM input element
     * of type "reset", then this default string is used.
     *
     * @deprecated As of 1.3, value comes from UIManager UIManager property
     *             FormView.resetButtonText
     */
    @Deprecated
    public static final String RESET = new String("Reset");

    
Document attribute name for storing POST data. JEditorPane.getPostData()
uses the same name, should be kept in sync.
/**
     * Document attribute name for storing POST data. JEditorPane.getPostData()
     * uses the same name, should be kept in sync.
     */
    static final String PostDataProperty = "javax.swing.JEditorPane.postdata";

    
Used to indicate if the maximum span should be the same as the
preferred span. This is used so that the Component's size doesn't
change if there is extra room on a line. The first bit is used for
the X direction, and the second for the y direction.
/**
     * Used to indicate if the maximum span should be the same as the
     * preferred span. This is used so that the Component's size doesn't
     * change if there is extra room on a line. The first bit is used for
     * the X direction, and the second for the y direction.
     */
    private short maxIsPreferred;

    
Creates a new FormView object.
Params:
elem – the element to decorate/**
     * Creates a new FormView object.
     *
     * @param elem the element to decorate
     */
    public FormView(Element elem) {
        super(elem);
    }

    
Create the component.  This is basically a
big switch statement based upon the tag type
and html attributes of the associated element.
/**
     * Create the component.  This is basically a
     * big switch statement based upon the tag type
     * and html attributes of the associated element.
     */
    protected Component createComponent() {
        AttributeSet attr = getElement().getAttributes();
        HTML.Tag t = (HTML.Tag)
            attr.getAttribute(StyleConstants.NameAttribute);
        JComponent c = null;
        Object model = attr.getAttribute(StyleConstants.ModelAttribute);

        // Remove listeners previously registered in shared model
        // when a new UI component is replaced.  See bug 7189299.
        removeStaleListenerForModel(model);
        if (t == HTML.Tag.INPUT) {
            c = createInputComponent(attr, model);
        } else if (t == HTML.Tag.SELECT) {

            if (model instanceof OptionListModel) {
                @SuppressWarnings("unchecked")
                JList<?> list = new JList<>((ListModel) model);
                int size = HTML.getIntegerAttributeValue(attr,
                                                         HTML.Attribute.SIZE,
                                                         1);
                list.setVisibleRowCount(size);
                list.setSelectionModel((ListSelectionModel)model);
                c = new JScrollPane(list);
            } else {
                @SuppressWarnings("unchecked")
                JComboBox<?> tmp = new JComboBox<>((ComboBoxModel) model);
                c = tmp;
                maxIsPreferred = 3;
            }
        } else if (t == HTML.Tag.TEXTAREA) {
            JTextArea area = new JTextArea((Document) model);
            int rows = HTML.getIntegerAttributeValue(attr,
                                                     HTML.Attribute.ROWS,
                                                     1);
            area.setRows(rows);
            int cols = HTML.getIntegerAttributeValue(attr,
                                                     HTML.Attribute.COLS,
                                                     20);
            maxIsPreferred = 3;
            area.setColumns(cols);
            c = new JScrollPane(area,
                                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                                JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        }

        if (c != null) {
            c.setAlignmentY(1.0f);
        }
        return c;
    }


    
Creates a component for an <INPUT> element based on the
value of the "type" attribute.
Params:
attr – set of attributes associated with the <INPUT> element.
model – the value of the StyleConstants.ModelAttribute
Returns:
the component./**
     * Creates a component for an &lt;INPUT&gt; element based on the
     * value of the "type" attribute.
     *
     * @param attr set of attributes associated with the &lt;INPUT&gt; element.
     * @param model the value of the StyleConstants.ModelAttribute
     * @return the component.
     */
    private JComponent createInputComponent(AttributeSet attr, Object model) {
        JComponent c = null;
        String type = (String) attr.getAttribute(HTML.Attribute.TYPE);

        if (type.equals("submit") || type.equals("reset")) {
            String value = (String)
                attr.getAttribute(HTML.Attribute.VALUE);
            if (value == null) {
                if (type.equals("submit")) {
                    value = UIManager.getString("FormView.submitButtonText");
                } else {
                    value = UIManager.getString("FormView.resetButtonText");
                }
            }
            JButton button = new JButton(value);
            if (model != null) {
                button.setModel((ButtonModel)model);
                button.addActionListener(this);
            }
            c = button;
            maxIsPreferred = 3;
        } else if (type.equals("image")) {
            String srcAtt = (String) attr.getAttribute(HTML.Attribute.SRC);
            JButton button;
            try {
                URL base = ((HTMLDocument)getElement().getDocument()).getBase();
                URL srcURL = new URL(base, srcAtt);
                Icon icon = new ImageIcon(srcURL);
                button  = new JButton(icon);
            } catch (MalformedURLException e) {
                button = new JButton(srcAtt);
            }
            if (model != null) {
                button.setModel((ButtonModel)model);
                button.addMouseListener(new MouseEventListener());
            }
            c = button;
            maxIsPreferred = 3;
        } else if (type.equals("checkbox")) {
            c = new JCheckBox();
            if (model != null) {
                ((JCheckBox)c).setModel((JToggleButton.ToggleButtonModel) model);
            }
            maxIsPreferred = 3;
        } else if (type.equals("radio")) {
            c = new JRadioButton();
            if (model != null) {
                ((JRadioButton)c).setModel((JToggleButton.ToggleButtonModel)model);
            }
            maxIsPreferred = 3;
        } else if (type.equals("text")) {
            int size = HTML.getIntegerAttributeValue(attr,
                                                     HTML.Attribute.SIZE,
                                                     -1);
            JTextField field;
            if (size > 0) {
                field = new JTextField();
                field.setColumns(size);
            }
            else {
                field = new JTextField();
                field.setColumns(20);
            }
            c = field;
            if (model != null) {
                field.setDocument((Document) model);
            }
            field.addActionListener(this);
            maxIsPreferred = 3;
        } else if (type.equals("password")) {
            JPasswordField field = new JPasswordField();
            c = field;
            if (model != null) {
                field.setDocument((Document) model);
            }
            int size = HTML.getIntegerAttributeValue(attr,
                                                     HTML.Attribute.SIZE,
                                                     -1);
            field.setColumns((size > 0) ? size : 20);
            field.addActionListener(this);
            maxIsPreferred = 3;
        } else if (type.equals("file")) {
            JTextField field = new JTextField();
            if (model != null) {
                field.setDocument((Document)model);
            }
            int size = HTML.getIntegerAttributeValue(attr, HTML.Attribute.SIZE,
                                                     -1);
            field.setColumns((size > 0) ? size : 20);
            JButton browseButton = new JButton(UIManager.getString
                                           ("FormView.browseFileButtonText"));
            Box box = Box.createHorizontalBox();
            box.add(field);
            box.add(Box.createHorizontalStrut(5));
            box.add(browseButton);
            browseButton.addActionListener(new BrowseFileAction(
                                           attr, (Document)model));
            c = box;
            maxIsPreferred = 3;
        }
        return c;
    }

    private void removeStaleListenerForModel(Object model) {
        if (model instanceof DefaultButtonModel) {
            // case of JButton whose model is DefaultButtonModel
            // Need to remove stale ActionListener, ChangeListener and
            // ItemListener that are instance of AbstractButton$Handler.
            DefaultButtonModel buttonModel = (DefaultButtonModel) model;
            String listenerClass = "javax.swing.AbstractButton$Handler";
            for (ActionListener listener : buttonModel.getActionListeners()) {
                if (listenerClass.equals(listener.getClass().getName())) {
                    buttonModel.removeActionListener(listener);
                }
            }
            for (ChangeListener listener : buttonModel.getChangeListeners()) {
                if (listenerClass.equals(listener.getClass().getName())) {
                    buttonModel.removeChangeListener(listener);
                }
            }
            for (ItemListener listener : buttonModel.getItemListeners()) {
                if (listenerClass.equals(listener.getClass().getName())) {
                    buttonModel.removeItemListener(listener);
                }
            }
        } else if (model instanceof AbstractListModel) {
            // case of JComboBox and JList
            // For JList, the stale ListDataListener is instance
            // BasicListUI$Handler.
            // For JComboBox, there are 2 stale ListDataListeners, which are
            // BasicListUI$Handler and BasicComboBoxUI$Handler.
            @SuppressWarnings("unchecked")
            AbstractListModel<?> listModel = (AbstractListModel) model;
            String listenerClass1 =
                    "javax.swing.plaf.basic.BasicListUI$Handler";
            String listenerClass2 =
                    "javax.swing.plaf.basic.BasicComboBoxUI$Handler";
            for (ListDataListener listener : listModel.getListDataListeners()) {
                if (listenerClass1.equals(listener.getClass().getName())
                        || listenerClass2.equals(listener.getClass().getName()))
                {
                    listModel.removeListDataListener(listener);
                }
            }
        } else if (model instanceof AbstractDocument) {
            // case of JPasswordField, JTextField and JTextArea
            // All have 2 stale DocumentListeners.
            String listenerClass1 =
                    "javax.swing.plaf.basic.BasicTextUI$UpdateHandler";
            String listenerClass2 =
                    "javax.swing.text.DefaultCaret$Handler";
            AbstractDocument docModel = (AbstractDocument) model;
            for (DocumentListener listener : docModel.getDocumentListeners()) {
                if (listenerClass1.equals(listener.getClass().getName())
                        || listenerClass2.equals(listener.getClass().getName()))
                {
                    docModel.removeDocumentListener(listener);
                }
            }
        }
    }

    
Determines the maximum span for this view along an
axis. For certain components, the maximum and preferred span are the
same. For others this will return the value
returned by Component.getMaximumSize along the
axis of interest.
Params:
axis – may be either View.X_AXIS or View.Y_AXIS
Throws:
IllegalArgumentException – for an invalid axis
Returns:
  the span the view would like to be rendered into >= 0.
          Typically the view is told to render into the span
          that is returned, although there is no guarantee.
          The parent may choose to resize or break the view./**
     * Determines the maximum span for this view along an
     * axis. For certain components, the maximum and preferred span are the
     * same. For others this will return the value
     * returned by Component.getMaximumSize along the
     * axis of interest.
     *
     * @param axis may be either View.X_AXIS or View.Y_AXIS
     * @return   the span the view would like to be rendered into &gt;= 0.
     *           Typically the view is told to render into the span
     *           that is returned, although there is no guarantee.
     *           The parent may choose to resize or break the view.
     * @exception IllegalArgumentException for an invalid axis
     */
    public float getMaximumSpan(int axis) {
        switch (axis) {
        case View.X_AXIS:
            if ((maxIsPreferred & 1) == 1) {
                super.getMaximumSpan(axis);
                return getPreferredSpan(axis);
            }
            return super.getMaximumSpan(axis);
        case View.Y_AXIS:
            if ((maxIsPreferred & 2) == 2) {
                super.getMaximumSpan(axis);
                return getPreferredSpan(axis);
            }
            return super.getMaximumSpan(axis);
        default:
            break;
        }
        return super.getMaximumSpan(axis);
    }


    
Responsible for processing 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.
Params:
evt – the ActionEvent./**
     * Responsible for processing 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();
        StringBuilder dataBuffer = new StringBuilder();
        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.
Params:
data – data to submit/**
     * This method is responsible for submitting the form data.
     * A thread is forked to undertake the submission.
     *
     * @param data data to submit
     */
    protected void submitData(String data) {
        Element form = getFormElement();
        AttributeSet attrs = form.getAttributes();
        HTMLDocument doc = (HTMLDocument) form.getDocument();
        URL base = doc.getBase();

        String target = (String) attrs.getAttribute(HTML.Attribute.TARGET);
        if (target == null) {
            target = "_self";
        }

        String method = (String) attrs.getAttribute(HTML.Attribute.METHOD);
        if (method == null) {
            method = "GET";
        }
        method = method.toLowerCase();
        boolean isPostMethod = method.equals("post");
        if (isPostMethod) {
            storePostData(doc, target, data);
        }

        String action = (String) attrs.getAttribute(HTML.Attribute.ACTION);
        URL actionURL;
        try {
            actionURL = (action == null)
                ? new URL(base.getProtocol(), base.getHost(),
                                        base.getPort(), base.getFile())
                : new URL(base, action);
            if (!isPostMethod) {
                String query = data.toString();
                actionURL = new URL(actionURL + "?" + query);
            }
        } catch (MalformedURLException e) {
            actionURL = null;
        }
        final JEditorPane c = (JEditorPane) getContainer();
        HTMLEditorKit kit = (HTMLEditorKit) c.getEditorKit();

        FormSubmitEvent formEvent = null;
        if (!kit.isAutoFormSubmission() || doc.isFrameDocument()) {
            FormSubmitEvent.MethodType methodType = isPostMethod
                    ? FormSubmitEvent.MethodType.POST
                    : FormSubmitEvent.MethodType.GET;
            formEvent = new FormSubmitEvent(
                    FormView.this, HyperlinkEvent.EventType.ACTIVATED,
                    actionURL, form, target, methodType, data);

        }
        // setPage() may take significant time so schedule it to run later.
        final FormSubmitEvent fse = formEvent;
        final URL url = actionURL;
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                if (fse != null) {
                    c.fireHyperlinkUpdate(fse);
                } else {
                    try {
                        c.setPage(url);
                    } catch (IOException e) {
                        UIManager.getLookAndFeel().provideErrorFeedback(c);
                    }
                }
            }
        });
    }

    private void storePostData(HTMLDocument doc, String target, String data) {

        /* POST data is stored into the document property named by constant
         * PostDataProperty from where it is later retrieved by method
         * JEditorPane.getPostData().  If the current document is in a frame,
         * the data is initially put into the toplevel (frameset) document
         * property (named <PostDataProperty>.<Target frame name>).  It is the
         * responsibility of FrameView which updates the target frame
         * to move data from the frameset document property into the frame
         * document property.
         */

        Document propDoc = doc;
        String propName = PostDataProperty;

        if (doc.isFrameDocument()) {
            // find the top-most JEditorPane holding the frameset view.
            FrameView.FrameEditorPane p =
                    (FrameView.FrameEditorPane) getContainer();
            FrameView v = p.getFrameView();
            JEditorPane c = v.getOutermostJEditorPane();
            if (c != null) {
                propDoc = c.getDocument();
                propName += ("." + target);
            }
        }

        propDoc.putProperty(propName, data);
    }

    
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.
/**
     * 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 <INPUT> form
element of type "image".
Params:
imageData – the mouse click coordinates./**
     * 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) {

        StringBuilder dataBuffer = new StringBuilder();
        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
Params:
point – associated with the mouse click.
Returns:
the image data./**
     * 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.
     */
    @SuppressWarnings("deprecation")
    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.isEmpty()) {
            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 FORM.
/**
     * 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.
Params:
buffer –        the buffer that contains that data to submit/**
     * 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
     */
    private void getFormData(StringBuilder 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") &&
                        next != getElement()) {
                        // do nothing - this submit is not the trigger
                    } else if (type == null || !type.equals("image")) {
                        // images only result in data if they triggered
                        // the submit and they require that the mouse click
                        // coords be appended to the data.  Hence its
                        // processing is handled by the view.
                        loadElementDataIntoBuffer(next, buffer);
                    }
                }
            }
        }
    }

    
Loads the data
associated with the element into the buffer.
The format in which data is appended depends
on the type of the form element.  Essentially
data is loaded in name/value pairs.
/**
     * Loads the data
     * associated with the element into the buffer.
     * The format in which data is appended depends
     * on the type of the form element.  Essentially
     * data is loaded in name/value pairs.
     *
     */
    private void loadElementDataIntoBuffer(Element elem, StringBuilder buffer) {

        AttributeSet attr = elem.getAttributes();
        String name = (String)attr.getAttribute(HTML.Attribute.NAME);
        if (name == null) {
            return;
        }
        String value = null;
        HTML.Tag tag = (HTML.Tag)elem.getAttributes().getAttribute
                                  (StyleConstants.NameAttribute);

        if (tag == HTML.Tag.INPUT) {
            value = getInputElementData(attr);
        } else if (tag ==  HTML.Tag.TEXTAREA) {
            value = getTextAreaData(attr);
        } else if (tag == HTML.Tag.SELECT) {
            loadSelectData(attr, buffer);
        }

        if (name != null && value != null) {
            appendBuffer(buffer, name, value);
        }
    }


    
Returns the data associated with an <INPUT> form
element.  The value of "type" attributes is
used to determine the type of the model associated
with the element and then the relevant data is
extracted.
/**
     * Returns the data associated with an &lt;INPUT&gt; form
     * element.  The value of "type" attributes is
     * used to determine the type of the model associated
     * with the element and then the relevant data is
     * extracted.
     */
    private String getInputElementData(AttributeSet attr) {

        Object model = attr.getAttribute(StyleConstants.ModelAttribute);
        String type = (String) attr.getAttribute(HTML.Attribute.TYPE);
        String value = null;

        if (type.equals("text") || type.equals("password")) {
            Document doc = (Document)model;
            try {
                value = doc.getText(0, doc.getLength());
            } catch (BadLocationException e) {
                value = null;
            }
        } else if (type.equals("submit") || type.equals("hidden")) {
            value = (String) attr.getAttribute(HTML.Attribute.VALUE);
            if (value == null) {
                value = "";
            }
        } else if (type.equals("radio") || type.equals("checkbox")) {
            ButtonModel m = (ButtonModel)model;
            if (m.isSelected()) {
                value = (String) attr.getAttribute(HTML.Attribute.VALUE);
                if (value == null) {
                    value = "on";
                }
            }
        } else if (type.equals("file")) {
            Document doc = (Document)model;
            String path;

            try {
                path = doc.getText(0, doc.getLength());
            } catch (BadLocationException e) {
                path = null;
            }
            if (path != null && path.length() > 0) {
                value = path;
            }
        }
        return value;
    }

    
Returns the data associated with the <TEXTAREA> form
element.  This is done by getting the text stored in the
Document model.
/**
     * Returns the data associated with the &lt;TEXTAREA&gt; form
     * element.  This is done by getting the text stored in the
     * Document model.
     */
    private String getTextAreaData(AttributeSet attr) {
        Document doc = (Document)attr.getAttribute(StyleConstants.ModelAttribute);
        try {
            return doc.getText(0, doc.getLength());
        } catch (BadLocationException e) {
            return null;
        }
    }


    
Loads the buffer with the data associated with the Select
form element.  Basically, only items that are selected
and have their name attribute set are added to the buffer.
/**
     * Loads the buffer with the data associated with the Select
     * form element.  Basically, only items that are selected
     * and have their name attribute set are added to the buffer.
     */
    private void loadSelectData(AttributeSet attr, StringBuilder buffer) {

        String name = (String)attr.getAttribute(HTML.Attribute.NAME);
        if (name == null) {
            return;
        }
        Object m = attr.getAttribute(StyleConstants.ModelAttribute);
        if (m instanceof OptionListModel) {
            @SuppressWarnings("unchecked")
            OptionListModel<Option> model = (OptionListModel<Option>) m;

            for (int i = 0; i < model.getSize(); i++) {
                if (model.isSelectedIndex(i)) {
                    Option option = model.getElementAt(i);
                    if (option != null) {
                        String value = option.getValue();
                        if (value != null) {
                            appendBuffer(buffer, name, value);
                        }
                    }
                }
            }
        } else if (m instanceof ComboBoxModel) {
            @SuppressWarnings("unchecked")
            ComboBoxModel<?> model = (ComboBoxModel)m;
            Option option = (Option)model.getSelectedItem();
            if (option != null) {
                String value = option.getValue();
                if (value != null) {
                    appendBuffer(buffer, name, value);
                }
            }
        }
    }

    
Appends name / value pairs into the
buffer.  Both names and values are encoded using the
URLEncoder.encode() method before being added to the
buffer.
/**
     * Appends name / value pairs into the
     * buffer.  Both names and values are encoded using the
     * URLEncoder.encode() method before being added to the
     * buffer.
     */
    @SuppressWarnings("deprecation")
    private void appendBuffer(StringBuilder buffer, String name, String value) {
        if (buffer.length() > 0) {
            buffer.append('&');
        }
        String encodedName = URLEncoder.encode(name);
        buffer.append(encodedName);
        buffer.append('=');
        String encodedValue = URLEncoder.encode(value);
        buffer.append(encodedValue);
    }

    
Returns true if the Element elem represents a control.
/**
     * Returns true if the Element <code>elem</code> represents a control.
     */
    private boolean isControl(Element elem) {
        return elem.isLeaf();
    }

    
Iterates over the element hierarchy to determine if
the element parameter, which is assumed to be an
<INPUT> element of type password or text, is the last
one of either kind, in the form to which it belongs.
/**
     * Iterates over the element hierarchy to determine if
     * the element parameter, which is assumed to be an
     * &lt;INPUT&gt; element of type password or text, is the last
     * one of either kind, in the form to which it belongs.
     */
    boolean isLastTextOrPasswordField() {
        Element parent = getFormElement();
        Element elem = getElement();

        if (parent != null) {
            ElementIterator it = new ElementIterator(parent);
            Element next;
            boolean found = false;

            while ((next = it.next()) != null) {
                if (next == elem) {
                    found = true;
                }
                else if (found && isControl(next)) {
                    AttributeSet elemAttr = next.getAttributes();

                    if (HTMLDocument.matchNameAttribute
                                     (elemAttr, HTML.Tag.INPUT)) {
                        String type = (String)elemAttr.getAttribute
                                                  (HTML.Attribute.TYPE);

                        if ("text".equals(type) || "password".equals(type)) {
                            return false;
                        }
                    }
                }
            }
        }
        return true;
    }

    
Resets the form
to its initial state by reinitializing the models
associated with each form element to their initial
values.
param elem the element that triggered the reset
/**
     * Resets the form
     * to its initial state by reinitializing the models
     * associated with each form element to their initial
     * values.
     *
     * param elem the element that triggered the reset
     */
    void resetForm() {
        Element parent = getFormElement();

        if (parent != null) {
            ElementIterator it = new ElementIterator(parent);
            Element next;

            while((next = it.next()) != null) {
                if (isControl(next)) {
                    AttributeSet elemAttr = next.getAttributes();
                    Object m = elemAttr.getAttribute(StyleConstants.
                                                     ModelAttribute);
                    if (m instanceof TextAreaDocument) {
                        TextAreaDocument doc = (TextAreaDocument)m;
                        doc.reset();
                    } else if (m instanceof PlainDocument) {
                        try {
                            PlainDocument doc =  (PlainDocument)m;
                            doc.remove(0, doc.getLength());
                            if (HTMLDocument.matchNameAttribute
                                             (elemAttr, HTML.Tag.INPUT)) {
                                String value = (String)elemAttr.
                                           getAttribute(HTML.Attribute.VALUE);
                                if (value != null) {
                                    doc.insertString(0, value, null);
                                }
                            }
                        } catch (BadLocationException e) {
                        }
                    } else if (m instanceof OptionListModel) {
                        @SuppressWarnings("unchecked")
                        OptionListModel<?> model = (OptionListModel) m;
                        int size = model.getSize();
                        for (int i = 0; i < size; i++) {
                            model.removeIndexInterval(i, i);
                        }
                        BitSet selectionRange = model.getInitialSelection();
                        for (int i = 0; i < selectionRange.size(); i++) {
                            if (selectionRange.get(i)) {
                                model.addSelectionInterval(i, i);
                            }
                        }
                    } else if (m instanceof OptionComboBoxModel) {
                        @SuppressWarnings("unchecked")
                        OptionComboBoxModel<?> model = (OptionComboBoxModel) m;
                        Option option = model.getInitialSelection();
                        if (option != null) {
                            model.setSelectedItem(option);
                        }
                    } else if (m instanceof JToggleButton.ToggleButtonModel) {
                        boolean checked = ((String)elemAttr.getAttribute
                                           (HTML.Attribute.CHECKED) != null);
                        JToggleButton.ToggleButtonModel model =
                                        (JToggleButton.ToggleButtonModel)m;
                        model.setSelected(checked);
                    }
                }
            }
        }
    }


    
BrowseFileAction is used for input type == file. When the user
clicks the button a JFileChooser is brought up allowing the user
to select a file in the file system. The resulting path to the selected
file is set in the text field (actually an instance of Document).
/**
     * BrowseFileAction is used for input type == file. When the user
     * clicks the button a JFileChooser is brought up allowing the user
     * to select a file in the file system. The resulting path to the selected
     * file is set in the text field (actually an instance of Document).
     */
    private class BrowseFileAction implements ActionListener {
        private AttributeSet attrs;
        private Document model;

        BrowseFileAction(AttributeSet attrs, Document model) {
            this.attrs = attrs;
            this.model = model;
        }

        public void actionPerformed(ActionEvent ae) {
            // PENDING: When mime support is added to JFileChooser use the
            // accept value of attrs.
            JFileChooser fc = new JFileChooser();
            fc.setMultiSelectionEnabled(false);
            if (fc.showOpenDialog(getContainer()) ==
                  JFileChooser.APPROVE_OPTION) {
                File selected = fc.getSelectedFile();

                if (selected != null) {
                    try {
                        if (model.getLength() > 0) {
                            model.remove(0, model.getLength());
                        }
                        model.insertString(0, selected.getPath(), null);
                    } catch (BadLocationException ble) {}
                }
            }
        }
    }
}