/*
* 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.io.Serializable;
/**
* Variables provide access to a global set of values accessible via XPath.
* XPath can reference variables using the <code>"$varname"</code> syntax.
* To use a custom implementation of this interface, pass it to
* {@link JXPathContext#setVariables JXPathContext.setVariables()}
*
* @author Dmitri Plotnikov
* @version $Revision: 652925 $ $Date: 2008-05-02 17:05:41 -0500 (Fri, 02 May 2008) $
*/
public interface Variables extends Serializable {
/**
* Returns true if the specified variable is declared.
* @param varName variable name
* @return boolean
*/
boolean isDeclaredVariable(String varName);
/**
* Returns the value of the specified variable.
* @param varName variable name
* @return Object value
* @throws IllegalArgumentException if there is no such variable.
*/
Object getVariable(String varName);
/**
* Defines a new variable with the specified value or modifies
* the value of an existing variable.
* May throw UnsupportedOperationException.
* @param varName variable name
* @param value to declare
*/
void declareVariable(String varName, Object value);
/**
* Removes an existing variable. May throw UnsupportedOperationException.
*
* @param varName is a variable name without the "$" sign
*/
void undeclareVariable(String varName);
}
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