/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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.jbpm.jpdl.el;
/**
* <p>This class is used to customize the way an ExpressionEvaluator resolves
* variable references at evaluation time. For example, instances of this class can
* implement their own variable lookup mechanisms, or introduce the
* notion of "implicit variables" which override any other variables.
* An instance of this class should be passed when evaluating
* an expression.</p>
*
* <p>An instance of this class includes the context against which resolution
* will happen</p>
*
* @since 2.0
*/
public interface VariableResolver
{
//-------------------------------------
/**
* Resolves the specified variable.
* Returns null if the variable is not found.
*
* @param pName the name of the variable to resolve
* @return the result of the variable resolution
*
* @throws ELException if a failure occurred while trying to resolve
* the given variable
**/
public Object resolveVariable (String pName)
throws ELException;
//-------------------------------------
}