elementtreepanel.java

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/*
 * @(#)ElementTreePanel.java	1.6 98/08/26
 *
 * Copyright 1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.tree.*;
import javax.swing.undo.*;
import java.awt.*;
import java.util.*;

/**
 * Displays a tree showing all the elements in a text Document. Selecting
 * a node will result in reseting the selection of the JTextComponent.
 * This also becomes a CaretListener to know when the selection has changed
 * in the text to update the selected item in the tree.
 *
 * @author Scott Violet
 * @version 1.6 08/26/98
 */
public class ElementTreePanel extends JPanel implements CaretListener, DocumentListener, TreeSelectionListener {
    /** Tree showing the documents element structure. */
    protected JTree             tree;
    /** Text component showing elemenst for. */
    protected JTextComponent    editor;
    /** Model for the tree. */
    protected ElementTreeModel  treeModel;
    /** Set to true when updatin the selection. */
    protected boolean           updatingSelection;

    public ElementTreePanel(JTextComponent editor) {
	this.editor = editor;

	Document document = editor.getDocument();

	// Create the tree.
	treeModel = new ElementTreeModel(document);
	tree = new JTree(treeModel) {
	    public String convertValueToText(Object value, boolean selected,
					     boolean expanded, boolean leaf,
					     int row, boolean hasFocus) {
		// Should only happen for the root
		if(!(value instanceof Element))
		    return value.toString();

		Element        e = (Element)value;
		AttributeSet   as = e.getAttributes().copyAttributes();
		String         asString;

		if(as != null) {
		    StringBuffer       retBuffer = new StringBuffer("[");
		    Enumeration        names = as.getAttributeNames();

		    while(names.hasMoreElements()) {
			Object        nextName = names.nextElement();

			if(nextName != StyleConstants.ResolveAttribute) {
			    retBuffer.append(" ");
			    retBuffer.append(nextName);
			    retBuffer.append("=");
			    retBuffer.append(as.getAttribute(nextName));
			}
		    }
		    retBuffer.append(" ]");
		    asString = retBuffer.toString();
		}
		else
		    asString = "[ ]";

		if(e.isLeaf())
		    return e.getName() + " [" + e.getStartOffset() +
			", " + e.getEndOffset() +"] Attributes: " + asString;
		return e.getName() + " [" + e.getStartOffset() +
		    ", " + e.getEndOffset() + "] Attributes: " +
 		        asString;
	    }
	};
	tree.addTreeSelectionListener(this);
	// Don't show the root, it is fake.
	tree.setRootVisible(false);
	// Since the display value of every node after the insertion point
	// changes every time the text changes and we don't generate a change
	// event for all those nodes the display value can become off.
	// This can be seen as '...' instead of the complete string value.
	// This is a temporary workaround, increase the needed size by 15,
	// hoping that will be enough.
	tree.setCellRenderer(new DefaultTreeCellRenderer() {
	    public Dimension getPreferredSize() {
		Dimension retValue = super.getPreferredSize();
		if(retValue != null)
		    retValue.width += 15;
		return retValue;
	    }
	});
	// become a listener on the document to update the tree.
	document.addDocumentListener(this);

	// Become a CaretListener
	editor.addCaretListener(this);

	// configure the panel and frame containing it.
	setLayout(new BorderLayout());
	add(new JScrollPane(tree), BorderLayout.CENTER);

	// Add a label above tree to describe what is being shown
	JLabel     label = new JLabel("Elements that make up the current document", SwingConstants.CENTER);

	label.setFont(new Font("Dialog", Font.BOLD, 14));
	add(label, BorderLayout.NORTH);

	setPreferredSize(new Dimension(250, 250));
    }


    // DocumentListener

    /**
     * Gives notification that there was an insert into the document.  The
     * given range bounds the freshly inserted region.
     *
     * @param e the document event
     */
    public void insertUpdate(DocumentEvent e) {
	updateTree(e);
    }

    /**
     * Gives notification that a portion of the document has been
     * removed.  The range is given in terms of what the view last
     * saw (that is, before updating sticky positions).
     *
     * @param e the document event
     */
    public void removeUpdate(DocumentEvent e) {
	updateTree(e);
    }

    /**
     * Gives notification that an attribute or set of attributes changed.
     *
     * @param e the document event
     */
    public void changedUpdate(DocumentEvent e) {
	updateTree(e);
    }

    // CaretListener

    /**
     * Messaged when the selection in the editor has changed. Will update
     * the selection in the tree.
     */
    public void caretUpdate(CaretEvent e) {
	if(!updatingSelection) {
	    JTextComponent     editor = getEditor();
	    int                selBegin = Math.min(e.getDot(), e.getMark());
	    int                end = Math.max(e.getDot(), e.getMark());
	    Vector             paths = new Vector();
	    TreeModel          model = getTreeModel();
	    Object             root = model.getRoot();
	    int                rootCount = model.getChildCount(root);

	    // Build an array of all the paths to all the character elements
	    // in the selection.
	    for(int counter = 0; counter < rootCount; counter++) {
		int            start = selBegin;

		while(start <= end) {
		    TreePath    path = getPathForIndex(start, root,
				       (Element)model.getChild(root, counter));
		    Element     charElement = (Element)path.
			                       getLastPathComponent();

		    paths.addElement(path);
		    if(start >= charElement.getEndOffset())
			start++;
		    else
			start = charElement.getEndOffset();
		}
	    }

	    // If a path was found, select it (them).
	    int               numPaths = paths.size();

	    if(numPaths > 0) {
		TreePath[]    pathArray = new TreePath[numPaths];

		paths.copyInto(pathArray);
		updatingSelection = true;
		try {
		    getTree().setSelectionPaths(pathArray);
		    getTree().scrollPathToVisible(pathArray[0]);
		}
		finally {
		    updatingSelection = false;
		}
	    }
	}
    }

    // TreeSelectionListener

    /**
      * Called whenever the value of the selection changes.
      * @param e the event that characterizes the change.
      */
    public void valueChanged(TreeSelectionEvent e) {
	JTree       tree = getTree();

	if(!updatingSelection && tree.getSelectionCount() == 1) {
	    TreePath      selPath = tree.getSelectionPath();
	    Object        lastPathComponent = selPath.getLastPathComponent();

	    if(!(lastPathComponent instanceof DefaultMutableTreeNode)) {
		Element       selElement = (Element)lastPathComponent;

		updatingSelection = true;
		try {
		    getEditor().select(selElement.getStartOffset(),
				       selElement.getEndOffset());
		}
		finally {
		    updatingSelection = false;
		}
	    }
	}
    }

    // Local methods

    /**
     * @return tree showing elements.
     */
    protected JTree getTree() {
	return tree;
    }

    /**
     * @return JTextComponent showing elements for.
     */
    protected JTextComponent getEditor() {
	return editor;
    }