1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 * @LastModified: Oct 2017
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.xpath.internal.operations;
23
24 import com.sun.org.apache.xml.internal.utils.QName;
25 import com.sun.org.apache.xpath.internal.Expression;
26 import com.sun.org.apache.xpath.internal.ExpressionOwner;
27 import com.sun.org.apache.xpath.internal.XPathContext;
28 import com.sun.org.apache.xpath.internal.XPathVisitor;
29 import com.sun.org.apache.xpath.internal.objects.XObject;
30 import java.util.List;
31
32 /**
33 * The baseclass for a binary operation.
34 */
35 public class Operation extends Expression implements ExpressionOwner
36 {
37 static final long serialVersionUID = -3037139537171050430L;
38
39 /** The left operand expression.
40 * @serial */
41 protected Expression m_left;
42
43 /** The right operand expression.
44 * @serial */
45 protected Expression m_right;
46
47 /**
48 * This function is used to fixup variables from QNames to stack frame
49 * indexes at stylesheet build time.
50 * @param vars List of QNames that correspond to variables. This list
51 * should be searched backwards for the first qualified name that
52 * corresponds to the variable reference qname. The position of the
53 * QName in the vector from the start of the vector will be its position
54 * in the stack frame (but variables above the globalsTop value will need
55 * to be offset to the current stack frame).
56 */
57 public void fixupVariables(List<QName> vars, int globalsSize)
58 {
59 m_left.fixupVariables(vars, globalsSize);
60 m_right.fixupVariables(vars, globalsSize);
61 }
62
63
64 /**
65 * Tell if this expression or it's subexpressions can traverse outside
66 * the current subtree.
67 *
68 * @return true if traversal outside the context node's subtree can occur.
69 */
70 public boolean canTraverseOutsideSubtree()
71 {
72
73 if (null != m_left && m_left.canTraverseOutsideSubtree())
74 return true;
75
76 if (null != m_right && m_right.canTraverseOutsideSubtree())
77 return true;
78
79 return false;
80 }
81
82 /**
83 * Set the left and right operand expressions for this operation.
84 *
85 *
86 * @param l The left expression operand.
87 * @param r The right expression operand.
88 */
89 public void setLeftRight(Expression l, Expression r)
90 {
91 m_left = l;
92 m_right = r;
93 l.exprSetParent(this);
94 r.exprSetParent(this);
95 }
96
97 /**
98 * Execute a binary operation by calling execute on each of the operands,
99 * and then calling the operate method on the derived class.
100 *
101 *
102 * @param xctxt The runtime execution context.
103 *
104 * @return The XObject result of the operation.
105 *
106 * @throws javax.xml.transform.TransformerException
107 */
108 public XObject execute(XPathContext xctxt)
109 throws javax.xml.transform.TransformerException
110 {
111
112 XObject left = m_left.execute(xctxt, true);
113 XObject right = m_right.execute(xctxt, true);
114
115 XObject result = operate(left, right);
116 left.detach();
117 right.detach();
118 return result;
119 }
120
121 /**
122 * Apply the operation to two operands, and return the result.
123 *
124 *
125 * @param left non-null reference to the evaluated left operand.
126 * @param right non-null reference to the evaluated right operand.
127 *
128 * @return non-null reference to the XObject that represents the result of the operation.
129 *
130 * @throws javax.xml.transform.TransformerException
131 */
132 public XObject operate(XObject left, XObject right)
133 throws javax.xml.transform.TransformerException
134 {
135 return null; // no-op
136 }
137
138 /** @return the left operand of binary operation, as an Expression.
139 */
140 public Expression getLeftOperand(){
141 return m_left;
142 }
143
144 /** @return the right operand of binary operation, as an Expression.
145 */
146 public Expression getRightOperand(){
147 return m_right;
148 }
149
150 class LeftExprOwner implements ExpressionOwner
151 {
152 /**
153 * @see ExpressionOwner#getExpression()
154 */
155 public Expression getExpression()
156 {
157 return m_left;
158 }
159
160 /**
161 * @see ExpressionOwner#setExpression(Expression)
162 */
163 public void setExpression(Expression exp)
164 {
165 exp.exprSetParent(Operation.this);
166 m_left = exp;
167 }
168 }
169
170 /**
171 * @see com.sun.org.apache.xpath.internal.XPathVisitable#callVisitors(ExpressionOwner, XPathVisitor)
172 */
173 public void callVisitors(ExpressionOwner owner, XPathVisitor visitor)
174 {
175 if(visitor.visitBinaryOperation(owner, this))
176 {
177 m_left.callVisitors(new LeftExprOwner(), visitor);
178 m_right.callVisitors(this, visitor);
179 }
180 }
181
182 /**
183 * @see ExpressionOwner#getExpression()
184 */
185 public Expression getExpression()
186 {
187 return m_right;
188 }
189
190 /**
191 * @see ExpressionOwner#setExpression(Expression)
192 */
193 public void setExpression(Expression exp)
194 {
195 exp.exprSetParent(this);
196 m_right = exp;
197 }
198
199 /**
200 * @see Expression#deepEquals(Expression)
201 */
202 public boolean deepEquals(Expression expr)
203 {
204 if(!isSameClass(expr))
205 return false;
206
207 if(!m_left.deepEquals(((Operation)expr).m_left))
208 return false;
209
210 if(!m_right.deepEquals(((Operation)expr).m_right))
211 return false;
212
213 return true;
214 }
215 }