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1   /*
2    * Copyright 1999-2004 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.jxpath.ri.compiler;
17  
18  import org.apache.commons.jxpath.ri.QName;
19  import org.apache.commons.jxpath.ri.EvalContext;
20  
21  /***
22   * An element of the compile tree holding a variable reference.
23   *
24   * @author Dmitri Plotnikov
25   * @version $Revision: 1.9 $ $Date: 2004/02/29 14:17:38 $
26   */
27  public class VariableReference extends Expression {
28  
29      private QName varName;
30  
31      public VariableReference(QName varName) {
32          this.varName = varName;
33      }
34  
35      public QName getVariableName() {
36          return varName;
37      }
38  
39      public String toString() {
40          return "$" + varName;
41      }
42  
43      public boolean isContextDependent() {
44          return false;
45      }
46  
47      public boolean computeContextDependent() {
48          return false;
49      }
50  
51      public Object compute(EvalContext context) {
52          return computeValue(context);
53      }
54  
55      /***
56       * Returns the value of the variable.
57       */
58      public Object computeValue(EvalContext context) {
59          return context.getRootContext().getVariableContext(varName);
60      }
61  }