View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.jxpath.ri.compiler;
18  
19  import org.apache.commons.jxpath.ri.QName;
20  import org.apache.commons.jxpath.ri.EvalContext;
21  
22  /**
23   * An element of the compile tree holding a variable reference.
24   *
25   * @author Dmitri Plotnikov
26   * @version $Revision: 652845 $ $Date: 2008-05-02 13:46:46 -0400 (Fri, 02 May 2008) $
27   */
28  public class VariableReference extends Expression {
29  
30      private QName varName;
31  
32      /**
33       * Create a new VariableReference.
34       * @param varName variable name
35       */
36      public VariableReference(QName varName) {
37          this.varName = varName;
38      }
39  
40      /**
41       * Get the variable name.
42       * @return QName
43       */
44      public QName getVariableName() {
45          return varName;
46      }
47  
48      public String toString() {
49          return "$" + varName;
50      }
51  
52      public boolean isContextDependent() {
53          return false;
54      }
55  
56      public boolean computeContextDependent() {
57          return false;
58      }
59  
60      public Object compute(EvalContext context) {
61          return computeValue(context);
62      }
63  
64      /**
65       * Returns the value of the variable.
66       * @param context EvalContext against which to compute the variable's value.
67       * @return Object
68       */
69      public Object computeValue(EvalContext context) {
70          return context.getRootContext().getVariableContext(varName);
71      }
72  }