defaultmutabletreenode.java

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/* DefaultMutableTreeNode.java --
   Copyright (C) 2002, 2004, 2005, 2006,  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
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */


package javax.swing.tree;

import gnu.java.util.EmptyEnumeration;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.NoSuchElementException;
import java.util.Stack;
import java.util.Vector;


/**
 * A default implementation of the {@link MutableTreeNode} interface.
 *
 * @author Andrew Selkirk
 * @author Robert Schuster ([e-mail])
 */
public class DefaultMutableTreeNode
  implements Cloneable, MutableTreeNode, Serializable
{
  private static final long serialVersionUID = -4298474751201349152L;

  /**
   * An empty enumeration, returned by {@link #children()} if a node has no
   * children.
   */
  public static final Enumeration EMPTY_ENUMERATION =
    EmptyEnumeration.getInstance();

  /**
   * The parent of this node (possibly <code>null</code>).
   */
  protected MutableTreeNode parent;

  /**
   * The child nodes for this node (may be empty).
   */
  protected Vector children = new Vector();

  /**
   * userObject
   */
  protected transient Object userObject;

  /**
   * allowsChildren
   */
  protected boolean allowsChildren;

  /**
   * Creates a <code>DefaultMutableTreeNode</code> object.
   * This is equivalent to <code>DefaultMutableTreeNode(null, true)</code>.
   */
  public DefaultMutableTreeNode()
  {
    this(null, true);
  }

  /**
   * Creates a <code>DefaultMutableTreeNode</code> object with the given
   * user object attached to it. This is equivalent to 
   * <code>DefaultMutableTreeNode(userObject, true)</code>.
   *
   * @param userObject the user object (<code>null</code> permitted).
   */
  public DefaultMutableTreeNode(Object userObject)
  {
    this(userObject, true);
  }

  /**
   * Creates a <code>DefaultMutableTreeNode</code> object with the given
   * user object attached to it.
   *
   * @param userObject the user object (<code>null</code> permitted).
   * @param allowsChildren <code>true</code> if the code allows to add child
   * nodes, <code>false</code> otherwise
   */
  public DefaultMutableTreeNode(Object userObject, boolean allowsChildren)
  {
    this.userObject = userObject;
    this.allowsChildren = allowsChildren;
  }

  /**
   * Returns a clone of the node.  The clone contains a shallow copy of the 
   * user object, and does not copy the parent node or the child nodes.
   *
   * @return A clone of the node.
   */
  public Object clone()
  {
    return new DefaultMutableTreeNode(this.userObject, this.allowsChildren);
  }

  /**
   * Returns a string representation of the node.  This implementation returns
   * <code>getUserObject().toString()</code>, or <code>null</code> if there
   * is no user object.
   *
   * @return A string representation of the node (possibly <code>null</code>).
   */
  public String toString()
  {
    if (userObject == null)
      return null;

    return userObject.toString();
  }

  /**
   * Adds a new child node to this node and sets this node as the parent of
   * the child node.  The child node must not be an ancestor of this node.
   *
   * @param child the child node (<code>null</code> not permitted).
   *
   * @throws IllegalStateException if {@link #getAllowsChildren()} returns 
   *     <code>false</code>.
   * @throws IllegalArgumentException if {@link #isNodeAncestor} returns
   *     <code>true</code>. 
   * @throws IllegalArgumentException if <code>child</code> is 
   *     <code>null</code>.
   */
  public void add(MutableTreeNode child)
  {
    if (! allowsChildren)
      throw new IllegalStateException();
    
    if (child == null)
      throw new IllegalArgumentException();

    if (isNodeAncestor(child))
      throw new IllegalArgumentException("Cannot add ancestor node.");
    
    children.add(child);
    child.setParent(this);
  }

  /**
   * Returns the parent node of this node.
   *
   * @return The parent node (possibly <code>null</code>).
   */
  public TreeNode getParent()
  {
    return parent;
  }

  /**
   * Removes the child with the given index from this node.
   *
   * @param index the index (in the range <code>0</code> to 
   *     <code>getChildCount() - 1</code>).
   *     
   * @throws ArrayIndexOutOfBoundsException if <code>index</code> is outside 
   *         the valid range.
   */
  public void remove(int index)
  {
    MutableTreeNode child = (MutableTreeNode) children.remove(index);
    child.setParent(null);
  }

  /**
   * Removes the given child from this node and sets its parent to 
   * <code>null</code>.
   *
   * @param node the child node (<code>null</code> not permitted).
   * 
   * @throws IllegalArgumentException if <code>node</code> is not a child of 
   *     this node.
   * @throws IllegalArgumentException if <code>node</code> is null.
   */
  public void remove(MutableTreeNode node)
  {
    if (node == null)
      throw new IllegalArgumentException("Null 'node' argument.");
    if (node.getParent() != this)
      throw new IllegalArgumentException(
          "The given 'node' is not a child of this node.");
    children.remove(node);
    node.setParent(null);
  }

  /**
   * writeObject
   *
   * @param stream the output stream
   *
   * @exception IOException If an error occurs
   */
  private void writeObject(ObjectOutputStream stream)
    throws IOException
  {
    // TODO: Implement me.
  }

  /**
   * readObject
   *
   * @param stream the input stream
   *
   * @exception IOException If an error occurs
   * @exception ClassNotFoundException TODO
   */
  private void readObject(ObjectInputStream stream)
    throws IOException, ClassNotFoundException
  {
    // TODO: Implement me.
  }

  /**
   * Inserts given child node at the given index.
   *
   * @param node the child node (<code>null</code> not permitted).
   * @param index the index.
   * 
   * @throws IllegalArgumentException if <code>node</code> is 
   *     </code>null</code>.
   */
  public void insert(MutableTreeNode node, int index)
  {
    if (! allowsChildren)
      throw new IllegalStateException();

    if (node == null)
      throw new IllegalArgumentException("Null 'node' argument.");
    
    if (isNodeAncestor(node))
      throw new IllegalArgumentException("Cannot insert ancestor node.");

    children.insertElementAt(node, index);
  }

  /**
   * Returns a path to this node from the root.
   *
   * @return an array of tree nodes
   */
  public TreeNode[] getPath()
  {
    return getPathToRoot(this, 0);
  }

  /**
   * Returns an enumeration containing all children of this node.
   * <code>EMPTY_ENUMERATION</code> is returned if this node has no children.
   *
   * @return an enumeration of tree nodes
   */
  public Enumeration children()
  {
    if (children.size() == 0)
      return EMPTY_ENUMERATION;
    
    return children.elements();
  }

  /**
   * Set the parent node for this node.
   *
   * @param node the parent node
   */
  public void setParent(MutableTreeNode node)
  {
    parent = node;
  }

  /**
   * Returns the child node at a given index.
   *
   * @param index the index
   *
   * @return the child node
   */
  public TreeNode getChildAt(int index)
  {
    return (TreeNode) children.elementAt(index);
  }

  /**
   * Returns the number of children of this node.
   *
   * @return the number of children
   */
  public int getChildCount()
  {
    return children.size();
  }

  /**
   * Returns the index of the specified child node, or -1 if the node is not
   * in fact a child of this node.
   * 
   * @param node  the node (<code>null</code> not permitted).
   * 
   * @return The index of the specified child node, or -1.
   * 
   * @throws IllegalArgumentException if <code>node</code> is <code>null</code>.
   */
  public int getIndex(TreeNode node)
  {
    if (node == null)
      throw new IllegalArgumentException("Null 'node' argument.");
    return children.indexOf(node);
  }

  /**
   * Sets the flag that controls whether or not this node allows the addition / 
   * insertion of child nodes.  If the flag is set to <code>false</code>, any
   * existing children are removed.
   *
   * @param allowsChildren  the flag.
   */
  public void setAllowsChildren(boolean allowsChildren)
  {
    if (!allowsChildren)
      removeAllChildren();
    this.allowsChildren = allowsChildren;
  }

  /**
   * getAllowsChildren
   *
   * @return boolean
   */
  public boolean getAllowsChildren()
  {
    return allowsChildren;
  }

  /**
   * Sets the user object for this node
   *
   * @param userObject the user object
   */
  public void setUserObject(Object userObject)
  {
    this.userObject = userObject;
  }

  /**
   * Returns the user object attached to this node. <code>null</code> is
   * returned when no user object is set.
   *
   * @return the user object
   */
  public Object getUserObject()
  {
    return userObject;
  }

  /**
   * Removes this node from its parent.
   */
  public void removeFromParent()
  {
    parent.remove(this);
    parent = null;
  }

  /**
   * Removes all child nodes from this node.
   */
  public void removeAllChildren()
  {
    for (int i = getChildCount() - 1; i >= 0; i--)
      remove(i);
  }

  /**
   * Returns <code>true</code> if <code>node</code> is an ancestor of this
   * tree node, and <code>false</code> otherwise.  An ancestor node is any of:
   * <ul>
   * <li>this tree node;</li>
   * <li>the parent node (if there is one);</li>
   * <li>any ancestor of the parent node;</li>
   * </ul>
   * If <code>node</code> is <code>null</code>, this method returns 
   * <code>false</code>.
   * 
   * @param node  the node (<code>null</code> permitted).
   *
   * @return A boolean.
   */
  public boolean isNodeAncestor(TreeNode node)
  {
    if (node == null)
      return false;

    TreeNode current = this;

    while (current != null && current != node)
      current = current.getParent();

    return current == node;
  }

  /**
   * Returns <code>true</code> if <code>node</code> is a descendant of this
   * tree node, and <code>false</code> otherwise.  A descendant node is any of:
   * <ul>
   * <li>this tree node;</li>
   * <li>the child nodes belonging to this tree node, if there are any;</li>
   * <li>any descendants of the child nodes;</li>
   * </ul>
   * If <code>node</code> is <code>null</code>, this method returns 
   * <code>false</code>.
   * 
   * @param node  the node (<code>null</code> permitted).
   *
   * @return A boolean.
   */
  public boolean isNodeDescendant(DefaultMutableTreeNode node)
  {
    if (node == null)
      return false;

    TreeNode current = node;
    
    while (current != null
           && current != this)
      current = current.getParent();

    return current == this;
  }

  /**
   * getSharedAncestor
   *
   * @param node TODO
   *
   * @return TreeNode
   */
  public TreeNode getSharedAncestor(DefaultMutableTreeNode node)
  {
    TreeNode current = this;
    ArrayList list = new ArrayList();

    while (current != null)
      {
        list.add(current);
        current = current.getParent();
      }

    current = node;

    while (current != null)
      {
        if (list.contains(current))
          return current;

        current = current.getParent();
      }

    return null;
  }

  /**
   * isNodeRelated
   *
   * @param node TODO
   *
   * @return boolean
   */
  public boolean isNodeRelated(DefaultMutableTreeNode node)
  {
    if (node == null)
      return false;

    return node.getRoot() == getRoot();
  }

  /**
   * getDepth
   *
   * @return int
   */
  public int getDepth()
  {
    if ((! allowsChildren)
        || children.size() == 0)
      return 0;

    Stack stack = new Stack();
    stack.push(new Integer(0));
    TreeNode node = getChildAt(0);
    int depth = 0;
    int current = 1;
    
    while (! stack.empty())
      {
        if (node.getChildCount() != 0)
          {
            node = node.getChildAt(0);
            stack.push(new Integer(0));
            current++;
          }
        else
          {
            if (current > depth)
              depth = current;

            int size;
            int index;
            
            do
              {
                node = node.getParent();
                size = node.getChildCount();
                index = ((Integer) stack.pop()).intValue() + 1;
                current--;
              }
            while (index >= size
                   && node != this);

            if (index < size)
              {
                node = node.getChildAt(index);
                stack.push(new Integer(index));
                current++;
              }
          }
      }

    return depth;
  }

  /**
   * getLevel
   *
   * @return int
   */
  public int getLevel()
  {
    int count = -1;
    TreeNode current = this;

    do
      {
        current = current.getParent();
        count++;
      }
    while (current != null);

    return count;
  }

  /**
   * getPathToRoot
   *
   * @param node TODO
   * @param depth TODO
   *
   * @return TreeNode[]
   */
  protected TreeNode[] getPathToRoot(TreeNode node, int depth)
  {