StyledEditorKit.java

/* StyledEditorKit.java --
   Copyright (C) 2002, 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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02110-1301 USA.

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permission to link this library with independent modules to produce an
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package javax.swing.text;

import java.awt.Color;
import java.awt.event.ActionEvent;

import javax.swing.Action;
import javax.swing.JEditorPane;
import javax.swing.event.CaretEvent;
import javax.swing.event.CaretListener;

/**
 * An {@link EditorKit} that supports editing styled text.
 *
 * @author Andrew Selkirk
 * @author Roman Kennke (roman@kennke.org)
 */
public class StyledEditorKit extends DefaultEditorKit
{
  /** The serialVersionUID. */
  private static final long serialVersionUID = 7002391892985555948L;

  /**
   * Toggles the underline attribute for the selected text.
   */
  public static class UnderlineAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * Creates an instance of <code>UnderlineAction</code>.
     */
    public UnderlineAction()
    {
      super("font-underline");
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      JEditorPane editor = getEditor(event);
      StyledDocument doc = getStyledDocument(editor);
      Element el = doc.getCharacterElement(editor.getSelectionStart());
      boolean isUnderline = StyleConstants.isUnderline(el.getAttributes());
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setUnderline(atts, ! isUnderline);
      setCharacterAttributes(editor, atts, false);
    }
  }

  /**
   * Toggles the italic attribute for the selected text.
   */
  public static class ItalicAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * Creates an instance of <code>ItalicAction</code>.
     */
    public ItalicAction()
    {
      super("font-italic");
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      JEditorPane editor = getEditor(event);
      StyledDocument doc = getStyledDocument(editor);
      Element el = doc.getCharacterElement(editor.getSelectionStart());
      boolean isItalic = StyleConstants.isItalic(el.getAttributes());
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setItalic(atts, ! isItalic);
      setCharacterAttributes(editor, atts, false);
    }
  }

  /**
   * Toggles the bold attribute for the selected text.
   */
  public static class BoldAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * Creates an instance of <code>BoldAction</code>.
     */
    public BoldAction()
    {
      super("font-bold");
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      JEditorPane editor = getEditor(event);
      StyledDocument doc = getStyledDocument(editor);
      Element el = doc.getCharacterElement(editor.getSelectionStart());
      boolean isBold = StyleConstants.isBold(el.getAttributes());
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setBold(atts, ! isBold);
      setCharacterAttributes(editor, atts, false);
    }
  }

  /**
   * Sets the alignment attribute on the selected text.
   */
  public static class AlignmentAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * The aligment to set.
     */
    private int a;

    /**
     * Creates a new instance of <code>AlignmentAction</code> to set the
     * alignment to <code>a</code>.
     *
     * @param nm the name of the Action
     * @param a the alignment to set
     */
    public AlignmentAction(String nm, int a)
    {
      super(nm);
      this.a = a;
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setAlignment(atts, a);
      setParagraphAttributes(getEditor(event), atts, false);
    }
  }

  /**
   * Sets the foreground color attribute on the selected text.
   */
  public static class ForegroundAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * The foreground color to set.
     */
    private Color fg;

    /**
     * Creates a new instance of <code>ForegroundAction</code> to set the
     * foreground color to <code>fg</code>.
     *
     * @param nm the name of the Action
     * @param fg the foreground color to set
     */
    public ForegroundAction(String nm, Color fg)
    {
      super(nm);
      this.fg = fg;
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setForeground(atts, fg);
      setCharacterAttributes(getEditor(event), atts, false);
    }
  }

  /**
   * Sets the font size attribute on the selected text.
   */
  public static class FontSizeAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * The font size to set.
     */
    private int size;

    /**
     * Creates a new instance of <code>FontSizeAction</code> to set the
     * font size to <code>size</code>.
     *
     * @param nm the name of the Action
     * @param size the font size to set
     */
    public FontSizeAction(String nm, int size)
    {
      super(nm);
      this.size = size;
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setFontSize(atts, size);
      setCharacterAttributes(getEditor(event), atts, false);
    }
  }

  /**
   * Sets the font family attribute on the selected text.
   */
  public static class FontFamilyAction extends StyledEditorKit.StyledTextAction
  {
    /**
     * The font family to set.
     */
    private String family;

    /**
     * Creates a new instance of <code>FontFamilyAction</code> to set the
     * font family to <code>family</code>.
     *
     * @param nm the name of the Action
     * @param family the font family to set
     */
    public FontFamilyAction(String nm, String family)
    {
      super(nm);
      this.family = family;
    }

    /**
     * Performs the action.
     *
     * @param event the <code>ActionEvent</code> that describes the action
     */
    public void actionPerformed(ActionEvent event)
    {
      SimpleAttributeSet atts = new SimpleAttributeSet();
      StyleConstants.setFontFamily(atts, family);
      setCharacterAttributes(getEditor(event), atts, false);
    }
  }

  /**
   * The abstract superclass of all styled TextActions. This class
   * provides some useful methods to manipulate the text attributes.
   */
  public abstract static class StyledTextAction extends TextAction
  {
    /**
     * Creates a new instance of <code>StyledTextAction</code>.
     *
     * @param nm the name of the <code>StyledTextAction</code>
     */
    public StyledTextAction(String nm)
    {
      super(nm);
    }

    /**
     * Returns the <code>JEditorPane</code> component from which the
     * <code>ActionEvent</code> originated.
     *
     * @param event the <code>ActionEvent</code>
     * @return the <code>JEditorPane</code> component from which the
     *         <code>ActionEvent</code> originated
     */
    protected final JEditorPane getEditor(ActionEvent event)
    {
      return (JEditorPane) getTextComponent(event);
    }

    /**
     * Sets the specified character attributes on the currently selected
     * text of <code>editor</code>. If <code>editor</code> does not have
     * a selection, then the attributes are used as input attributes
     * for newly inserted content.
     *
     * @param editor the <code>JEditorPane</code> component
     * @param atts the text attributes to set
     * @param replace if <code>true</code> the current attributes of the
     *        selection are replaces, otherwise they are merged
     */
    protected final void setCharacterAttributes(JEditorPane editor,
                                                AttributeSet atts,
                                                boolean replace)
    {
      int p0 = editor.getSelectionStart();
      int p1 = editor.getSelectionEnd();
      if (p0 != p1)
        {
          StyledDocument doc = getStyledDocument(editor);
          doc.setCharacterAttributes(p0, p1 - p0, atts, replace);
        }
      // Update input attributes.
      StyledEditorKit kit = getStyledEditorKit(editor);
      MutableAttributeSet inputAtts = kit.getInputAttributes();
      if (replace)
        {
          inputAtts.removeAttributes(inputAtts);
        }
      inputAtts.addAttributes(atts);
    }

    /**
     * Returns the {@link StyledDocument} that is used by <code>editor</code>.
     *
     * @param editor the <code>JEditorPane</code> from which to get the
     *        <code>StyledDocument</code>
     *
     * @return the {@link StyledDocument} that is used by <code>editor</code>
     */
    protected final StyledDocument getStyledDocument(JEditorPane editor)
    {
      Document doc = editor.getDocument();
      if (!(doc instanceof StyledDocument))
	throw new AssertionError("The Document for StyledEditorKits is "
				 + "expected to be a StyledDocument.");

      return (StyledDocument) doc;
    }

    /**
     * Returns the {@link StyledEditorKit} that is used by <code>editor</code>.
     *
     * @param editor the <code>JEditorPane</code> from which to get the
     *        <code>StyledEditorKit</code>
     *
     * @return the {@link StyledEditorKit} that is used by <code>editor</code>
     */
    protected final StyledEditorKit getStyledEditorKit(JEditorPane editor)
    {
      EditorKit kit = editor.getEditorKit();
      if (!(kit instanceof StyledEditorKit))
	throw new AssertionError("The EditorKit for StyledDocuments is "
				 + "expected to be a StyledEditorKit.");

      return (StyledEditorKit) kit;
    }

    /**
     * Sets the specified character attributes on the paragraph that
     * contains the currently selected
     * text of <code>editor</code>. If <code>editor</code> does not have
     * a selection, then the attributes are set on the paragraph that
     * contains the current caret position.
     *
     * @param editor the <code>JEditorPane</code> component
     * @param atts the text attributes to set
     * @param replace if <code>true</code> the current attributes of the
     *        selection are replaces, otherwise they are merged
     */
    protected final void setParagraphAttributes(JEditorPane editor,
                                                AttributeSet atts,
                                                boolean replace)
    {
      Document doc = editor.getDocument();
      if (doc instanceof StyledDocument)
	{
	  StyledDocument styleDoc = (StyledDocument) editor.getDocument();
	  EditorKit kit = editor.getEditorKit();
	  if (!(kit instanceof StyledEditorKit))
	    {
	      StyledEditorKit styleKit = (StyledEditorKit) kit;
	      int start = editor.getSelectionStart();
	      int end = editor.getSelectionEnd();
	      int dot = editor.getCaret().getDot();
	      if (start == dot && end == dot)
		{
		  // If there is no selection, then we only update the
		  // input attributes.
		  MutableAttributeSet inputAttributes =
		    styleKit.getInputAttributes();
		  inputAttributes.addAttributes(atts);
		}
	      else
		styleDoc.setParagraphAttributes(start, end, atts, replace);
	    }
	  else
	    throw new AssertionError("The EditorKit for StyledTextActions "
				     + "is expected to be a StyledEditorKit");
	}
      else
	throw new AssertionError("The Document for StyledTextActions is "
				 + "expected to be a StyledDocument.");
    }
  }

  /**
   * A {@link ViewFactory} that is able to create {@link View}s for
   * the <code>Element</code>s that are supported by
   * <code>StyledEditorKit</code>, namely the following types of Elements:
   *
   * <ul>
   * <li>{@link AbstractDocument#ContentElementName}</li>
   * <li>{@link AbstractDocument#ParagraphElementName}</li>
   * <li>{@link AbstractDocument#SectionElementName}</li>
   * <li>{@link StyleConstants#ComponentElementName}</li>
   * <li>{@link StyleConstants#IconElementName}</li>
   * </ul>
   */
  static class StyledViewFactory
    implements ViewFactory
  {
    /**
     * Creates a {@link View} for the specified <code>Element</code>.
     *
     * @param element the <code>Element</code> to create a <code>View</code>
     *        for
     * @return the <code>View</code> for the specified <code>Element</code>
     *         or <code>null</code> if the type of <code>element</code> is
     *         not supported
     */
    public View create(Element element)
    {
      String name = element.getName();
      View view = null;
      if (name.equals(AbstractDocument.ContentElementName))
	view = new LabelView(element);
      else if (name.equals(AbstractDocument.ParagraphElementName))
	view = new ParagraphView(element);
      else if (name.equals(AbstractDocument.SectionElementName))
	view = new BoxView(element, View.Y_AXIS);
      else if (name.equals(StyleConstants.ComponentElementName))
	view = new ComponentView(element);
      else if (name.equals(StyleConstants.IconElementName))
	view = new IconView(element);
      else
        throw new AssertionError("Unknown Element type: "
                                 + element.getClass().getName() + " : "
                                 + name);
      return view;
    }
  }

  /**
   * Keeps track of the caret position and updates the currentRun
   * <code>Element</code> and the <code>inputAttributes</code>.
   */
  class CaretTracker
    implements CaretListener
  {
    /**
     * Notifies an update of the caret position.
     *
     * @param ev the event for the caret update
     */
    public void caretUpdate(CaretEvent ev)
    {
      Object source = ev.getSource();
      if (!(source instanceof JTextComponent))
	throw new AssertionError("CaretEvents are expected to come from a"
				 + "JTextComponent.");

      JTextComponent text = (JTextComponent) source;
      Document doc = text.getDocument();
      if (!(doc instanceof StyledDocument))
	throw new AssertionError("The Document used by StyledEditorKits is"
				 + "expected to be a StyledDocument");

      StyledDocument styleDoc = (StyledDocument) doc;
      currentRun = styleDoc.getCharacterElement(ev.getDot());
      createInputAttributes(currentRun, inputAttributes);
    }
  }

  /**
   * Stores the <code>Element</code> at the current caret position. This
   * is updated by {@link CaretTracker}.
   */
  Element currentRun;

  /**
   * The current input attributes. This is updated by {@link CaretTracker}.
   */
  MutableAttributeSet inputAttributes;

  /**
   * The CaretTracker that keeps track of the current input attributes, and
   * the current character run Element.
   */
  CaretTracker caretTracker;

  /**
   * The ViewFactory for StyledEditorKits.
   */
  StyledViewFactory viewFactory;

  /**
   * Creates a new instance of <code>StyledEditorKit</code>.
   */
  public StyledEditorKit()
  {
    inputAttributes = new SimpleAttributeSet();
  }

  /**
   * Creates an exact copy of this <code>StyledEditorKit</code>.
   *
   * @return an exact copy of this <code>StyledEditorKit</code>
   */
  public Object clone()
  {
    StyledEditorKit clone = (StyledEditorKit) super.clone();
    // FIXME: Investigate which fields must be copied.
    return clone;
  }

  /**
   * Returns the <code>Action</code>s supported by this {@link EditorKit}.
   * This includes the {@link BoldAction}, {@link ItalicAction} and
   * {@link UnderlineAction} as well as the <code>Action</code>s supported
   * by {@link DefaultEditorKit}.
   *
   * The other <code>Action</code>s of <code>StyledEditorKit</code> are not
   * returned here, since they require a parameter and thus custom
   * instantiation.
   *
   * @return the <code>Action</code>s supported by this {@link EditorKit}
   */
  public Action[] getActions()
  {
    Action[] actions1 = super.getActions();
    Action[] myActions = new Action[] { 
      new FontSizeAction("font-size-8", 8),
      new FontSizeAction("font-size-10", 10),
      new FontSizeAction("font-size-12", 12),
      new FontSizeAction("font-size-14", 14),
      new FontSizeAction("font-size-16", 16),
      new FontSizeAction("font-size-18", 18),
      new FontSizeAction("font-size-24", 24),
      new FontSizeAction("font-size-36", 36),
      new FontSizeAction("font-size-48", 48),
      new FontFamilyAction("font-family-Serif", "Serif"),
      new FontFamilyAction("font-family-Monospaced", "Monospaced"),
      new FontFamilyAction("font-family-SansSerif", "SansSerif"),
      new AlignmentAction("left-justify", StyleConstants.ALIGN_LEFT),
      new AlignmentAction("center-justify", StyleConstants.ALIGN_CENTER),
      new AlignmentAction("right-justify", StyleConstants.ALIGN_RIGHT),
      new BoldAction(),
      new ItalicAction(),
      new UnderlineAction()
    };
    return TextAction.augmentList(actions1, myActions);
  }

  /**
   * Returns the current input attributes. These are automatically set on
   * any newly inserted content, if not specified otherwise.
   *
   * @return the current input attributes
   */
  public MutableAttributeSet getInputAttributes()
  {
    return inputAttributes;
  }

  /**
   * Returns the {@link Element} that represents the character run at the
   * current caret position.
   *
   * @return the {@link Element} that represents the character run at the
   *         current caret position
   */
  public Element getCharacterAttributeRun()
  {
    return currentRun;
  }

  /**
   * Creates the default {@link Document} supported by this
   * <code>EditorKit</code>. This is an instance of
   * {@link DefaultStyledDocument} in this case but may be overridden by
   * subclasses.
   *
   * @return an instance of <code>DefaultStyledDocument</code>
   */
  public Document createDefaultDocument()
  {
    return new DefaultStyledDocument();
  }

  /**
   * Installs this <code>EditorKit</code> on the specified {@link JEditorPane}.
   * This basically involves setting up required listeners on the
   * <code>JEditorPane</code>.
   *
   * @param component the <code>JEditorPane</code> to install this
   *        <code>EditorKit</code> on
   */
  public void install(JEditorPane component)
  {
    CaretTracker tracker = new CaretTracker();
    component.addCaretListener(tracker);
  }

  /**
   * Deinstalls this <code>EditorKit</code> from the specified
   * {@link JEditorPane}. This basically involves removing all listeners from
   * <code>JEditorPane</code> that have been set up by this
   * <code>EditorKit</code>.
   *
   * @param component the <code>JEditorPane</code> from which to deinstall this
   *        <code>EditorKit</code>
   */
  public void deinstall(JEditorPane component)
  {
    CaretTracker t = caretTracker;
    if (t != null)
      component.removeCaretListener(t);
    caretTracker = null;
  }

  /**
   * Returns a {@link ViewFactory} that is able to create {@link View}s
   * for {@link Element}s that are supported by this <code>EditorKit</code>,
   * namely the following types of <code>Element</code>s:
   *
   * <ul>
   * <li>{@link AbstractDocument#ContentElementName}</li>
   * <li>{@link AbstractDocument#ParagraphElementName}</li>
   * <li>{@link AbstractDocument#SectionElementName}</li>
   * <li>{@link StyleConstants#ComponentElementName}</li>
   * <li>{@link StyleConstants#IconElementName}</li>
   * </ul>
   *
   * @return a {@link ViewFactory} that is able to create {@link View}s
   *          for {@link Element}s that are supported by this <code>EditorKit</code>
   */
  public ViewFactory getViewFactory()
  {
    if (viewFactory == null)
      viewFactory = new StyledViewFactory();
    return viewFactory;
  }

  /**
   * Copies the text attributes from <code>element</code> to <code>set</code>.
   * This is called everytime when the caret position changes to keep
   * track of the current input attributes. The attributes in <code>set</code>
   * are cleaned before adding the attributes of <code>element</code>.
   *
   * This method filters out attributes for element names, <code>Icon</code>s
   * and <code>Component</code>s.
   *
   * @param element the <code>Element</code> from which to copy the text
   *         attributes
   * @param set the inputAttributes to copy the attributes to
   */
  protected void createInputAttributes(Element element,
				       MutableAttributeSet set)
  {
    // FIXME: Filter out component, icon and element name attributes.
    set.removeAttributes(set);
    set.addAttributes(element.getAttributes());
  }
}