001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.jxpath.ri.compiler;
018
019 import org.apache.commons.jxpath.ri.QName;
020 import org.apache.commons.jxpath.ri.EvalContext;
021
022 /**
023 * An element of the compile tree holding a variable reference.
024 *
025 * @author Dmitri Plotnikov
026 * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
027 */
028 public class VariableReference extends Expression {
029
030 private QName varName;
031
032 /**
033 * Create a new VariableReference.
034 * @param varName variable name
035 */
036 public VariableReference(QName varName) {
037 this.varName = varName;
038 }
039
040 /**
041 * Get the variable name.
042 * @return QName
043 */
044 public QName getVariableName() {
045 return varName;
046 }
047
048 public String toString() {
049 return "$" + varName;
050 }
051
052 public boolean isContextDependent() {
053 return false;
054 }
055
056 public boolean computeContextDependent() {
057 return false;
058 }
059
060 public Object compute(EvalContext context) {
061 return computeValue(context);
062 }
063
064 /**
065 * Returns the value of the variable.
066 * @param context EvalContext against which to compute the variable's value.
067 * @return Object
068 */
069 public Object computeValue(EvalContext context) {
070 return context.getRootContext().getVariableContext(varName);
071 }
072 }