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1   /*
2    * Copyright (c) 2000, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.
8    *
9    * This code is distributed in the hope that it will be useful, but WITHOUT
10   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12   * version 2 for more details (a copy is included in the LICENSE file that
13   * accompanied this code).
14   *
15   * You should have received a copy of the GNU General Public License version
16   * 2 along with this work; if not, write to the Free Software Foundation,
17   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18   *
19   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20   * or visit www.oracle.com if you need additional information or have any
21   * questions.
22   *
23   */
24  
25  package sun.jvm.hotspot.utilities;
26  
27  /** This class implements a node in a red-black tree. It provides
28      accessors for the left and right children as well as the color of
29      the node. */
30  
31  public class RBNode {
32    private Object data;
33    private RBNode left;
34    private RBNode right;
35    private RBNode parent;
36    private RBColor color;
37  
38    /** Newly-created nodes are colored red */
39    public RBNode(Object data) {
40      this.data  = data;
41      color = RBColor.RED;
42    }
43  
44    public Object getData() {
45      return data;
46    }
47  
48    /** Must copy all user-defined fields from the given node. For
49        example, the base implementation copies the "data" field.
50        However, it does not (and must not) copy the link fields
51        (parent, left child, right child). It also does not need to copy
52        any computed information for the node, as the node will be
53        updated when necessary. Subclasses must be careful to call the
54        superclass implementation. */
55    public void copyFrom(RBNode arg) {
56      this.data  = arg.data;
57    }
58  
59    /** This is called by the base RBTree's insertion and deletion
60        methods when necessary. Subclasses can use this to update any
61        computed information based on the information in their left or
62        right children. For multi-node updates it is guaranteed that
63        this method will be called in the correct order. This should
64        return true if an update actually occurred, false if not. */
65    public boolean update() {
66      return false;
67    }
68  
69    public RBColor getColor()            { return color;         }
70    public void setColor(RBColor color)  { this.color = color;   }
71  
72    public RBNode getParent()            { return parent;        }
73    public void setParent(RBNode parent) { this.parent = parent; }
74  
75    /** Access to left child */
76    public RBNode getLeft()              { return left;          }
77    public void setLeft(RBNode left)     { this.left = left;     }
78  
79    /** Access to right child */
80    public RBNode getRight()             { return right;         }
81    public void setRight(RBNode right)   { this.right = right;   }
82  }