001    /* TreeNode.java --
002       Copyright (C) 2002, 2006, Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing.tree;
040    
041    import java.util.Enumeration;
042    
043    /**
044     * A tree node.
045     *
046     * @author Andrew Selkirk
047     */
048    public interface TreeNode
049    {
050    
051      /**
052       * Returns the parent node for this tree node, or <code>null</code> if this
053       * node has no parent.
054       *
055       * @return The parent node (possibly <code>null</code>).
056       */
057      TreeNode getParent();
058    
059      /**
060       * Returns the index of the specified child node, or -1 if the node is not
061       * in fact a child of this node.
062       *
063       * @param node  the node (<code>null</code> not permitted).
064       *
065       * @return The index of the specified child node, or -1.
066       *
067       * @throws IllegalArgumentException if <code>node</code> is <code>null</code>.
068       */
069      int getIndex(TreeNode node);
070    
071      /**
072       * Returns the child node at the given index.
073       *
074       * @param index  the index (in the range <code>0</code> to
075       *     <code>getChildCount() - 1</code>).
076       *
077       * @return The child node at the given index.
078       */
079      TreeNode getChildAt(int index);
080    
081      /**
082       * Returns the number of children for this node.
083       *
084       * @return The number of children for this node.
085       */
086      int getChildCount();
087    
088      /**
089       * Returns <code>true</code> if this node allows children, and
090       * <code>false</code> otherwise.
091       *
092       * @return A boolean.
093       */
094      boolean getAllowsChildren();
095    
096      /**
097       * Returns <code>true</code> if this node is a leaf node, and
098       * <code>false</code> otherwise.
099       *
100       * @return A boolean.
101       */
102      boolean isLeaf();
103    
104      /**
105       * Returns an enumeration of the children of this node, or an empty
106       * enumeration if this node has no children.
107       *
108       * @return An enumeration of the children of this node.
109       */
110      @SuppressWarnings("unchecked") // Required for API compatibility
111      Enumeration children();
112    
113    }