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Java > Open Source Codes > org > enhydra > apache > xerces > validators > common > CMBinOp


1 /*
2  * The Apache Software License, Version 1.1
3  *
4  *
5  * Copyright (c) 1999 The Apache Software Foundation. All rights
6  * reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  * notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  * notice, this list of conditions and the following disclaimer in
17  * the documentation and/or other materials provided with the
18  * distribution.
19  *
20  * 3. The end-user documentation included with the redistribution,
21  * if any, must include the following acknowledgment:
22  * "This product includes software developed by the
23  * Apache Software Foundation (http://www.apache.org/)."
24  * Alternately, this acknowledgment may appear in the software itself,
25  * if and wherever such third-party acknowledgments normally appear.
26  *
27  * 4. The names "Xerces" and "Apache Software Foundation" must
28  * not be used to endorse or promote products derived from this
29  * software without prior written permission. For written
30  * permission, please contact apache@apache.org.
31  *
32  * 5. Products derived from this software may not be called "Apache",
33  * nor may "Apache" appear in their name, without prior written
34  * permission of the Apache Software Foundation.
35  *
36  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
37  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
38  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
39  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
42  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
43  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
44  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
45  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
46  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
47  * SUCH DAMAGE.
48  * ====================================================================
49  *
50  * This software consists of voluntary contributions made by many
51  * individuals on behalf of the Apache Software Foundation and was
52  * originally based on software copyright (c) 1999, International
53  * Business Machines, Inc., http://www.apache.org. For more
54  * information on the Apache Software Foundation, please see
55  * <http://www.apache.org/>.
56  */
57
58 package org.enhydra.apache.xerces.validators.common;
59
60 import org.enhydra.apache.xerces.framework.XMLContentSpec;
61 import org.enhydra.apache.xerces.utils.ImplementationMessages;
62
63 /**
64  *
65  * @version
66  */
67 public class CMBinOp extends CMNode
68 {
69     // -------------------------------------------------------------------
70 // Constructors
71 // -------------------------------------------------------------------
72 public CMBinOp(int type, CMNode leftNode, CMNode rightNode) throws CMException
73     {
74         super(type);
75
76         // Insure that its one of the types we require
77 if ((type() != XMLContentSpec.CONTENTSPECNODE_CHOICE)
78         && (type() != XMLContentSpec.CONTENTSPECNODE_SEQ))
79         {
80             throw new CMException(ImplementationMessages.VAL_BST);
81         }
82
83         // Store the nodes and init any data that needs it
84 fLeftChild = leftNode;
85         fRightChild = rightNode;
86     }
87
88
89     // -------------------------------------------------------------------
90 // Package, final methods
91 // -------------------------------------------------------------------
92 final CMNode getLeft()
93     {
94         return fLeftChild;
95     }
96
97     final CMNode getRight()
98     {
99         return fRightChild;
100     }
101
102
103     // -------------------------------------------------------------------
104 // Package, inherited methods
105 // -------------------------------------------------------------------
106 boolean isNullable() throws CMException
107     {
108         //
109 // If its an alternation, then if either child is nullable then
110 // this node is nullable. If its a concatenation, then both of
111 // them have to be nullable.
112 //
113 if (type() == XMLContentSpec.CONTENTSPECNODE_CHOICE)
114             return (fLeftChild.isNullable() || fRightChild.isNullable());
115         else if (type() == XMLContentSpec.CONTENTSPECNODE_SEQ)
116             return (fLeftChild.isNullable() && fRightChild.isNullable());
117         else
118             throw new CMException(ImplementationMessages.VAL_BST);
119     }
120
121
122     // -------------------------------------------------------------------
123 // Protected, inherited methods
124 // -------------------------------------------------------------------
125 protected void calcFirstPos(CMStateSet toSet) throws CMException
126     {
127         if (type() == XMLContentSpec.CONTENTSPECNODE_CHOICE)
128         {
129             // Its the the union of the first positions of our children.
130 toSet.setTo(fLeftChild.firstPos());
131             toSet.union(fRightChild.firstPos());
132         }
133          else if (type() == XMLContentSpec.CONTENTSPECNODE_SEQ)
134         {
135             //
136 // If our left child is nullable, then its the union of our
137 // children's first positions. Else is our left child's first
138 // positions.
139 //
140 toSet.setTo(fLeftChild.firstPos());
141             if (fLeftChild.isNullable())
142                 toSet.union(fRightChild.firstPos());
143         }
144          else
145         {
146             throw new CMException(ImplementationMessages.VAL_BST);
147         }
148     }
149
150     protected void calcLastPos(CMStateSet toSet) throws CMException
151     {
152         if (type() == XMLContentSpec.CONTENTSPECNODE_CHOICE)
153         {
154             // Its the the union of the first positions of our children.
155 toSet.setTo(fLeftChild.lastPos());
156             toSet.union(fRightChild.lastPos());
157         }
158          else if (type() == XMLContentSpec.CONTENTSPECNODE_SEQ)
159         {
160             //
161 // If our right child is nullable, then its the union of our
162 // children's last positions. Else is our right child's last
163 // positions.
164 //
165 toSet.setTo(fRightChild.lastPos());
166             if (fRightChild.isNullable())
167                 toSet.union(fLeftChild.lastPos());
168         }
169          else
170         {
171             throw new CMException(ImplementationMessages.VAL_BST);
172         }
173     }
174
175
176     // -------------------------------------------------------------------
177 // Private data members
178 //
179 // fLeftChild
180 // fRightChild
181 // These are the references to the two nodes that are on either
182 // side of this binary operation.
183 // -------------------------------------------------------------------
184 private CMNode fLeftChild;
185     private CMNode fRightChild;
186 };
187
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