/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.jxpath;
import java.util.HashMap;
/**
* A basic implementation of the Variables interface that uses a HashMap.
*
* @author Dmitri Plotnikov
* @version $Revision: 652925 $ $Date: 2008-05-02 17:05:41 -0500 (Fri, 02 May 2008) $
*/
public class BasicVariables implements Variables {
private static final long serialVersionUID = 2708263960832062725L;
/**
* Contains the values of declared variables
*/
private HashMap vars = new HashMap();
/**
* Returns true if the variable has been defined, even if the
* value of the variable is null.
*
* @param varName is a variable name without the "$" sign
*
* @return true if the variable is declared
*/
public boolean isDeclaredVariable(String varName) {
return vars.containsKey(varName);
}
/**
* Returns the value of the variable if it is defined,
* otherwise, throws IllegalArgumentException
*
* @param varName is a variable name without the "$" sign
*
* @return the value of the variable
*/
public Object getVariable(String varName) {
// Note that a variable may be defined with a null value
if (vars.containsKey(varName)) {
return vars.get(varName);
}
throw new IllegalArgumentException(
"No such variable: '" + varName + "'");
}
/**
* Defines a new variable with the specified value or modifies
* the value of an existing variable.
*
* @param varName is a variable name without the "$" sign
* @param value is the new value for the variable, which can be null
*/
public void declareVariable(String varName, Object value) {
vars.put(varName, value);
}
/**
* Removes an existing variable. May throw UnsupportedOperationException.
*
* @param varName is a variable name without the "$" sign
*/
public void undeclareVariable(String varName) {
vars.remove(varName);
}
public String toString() {
return vars.toString();
}
}
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