package org.apache.archiva.redback.components.evaluator;

/*
 * 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.
 */

/**
 * ExpressionSource
 *
 * @author <a href="mailto:joakim@erdfelt.com">Joakim Erdfelt</a>
 *
 */
public interface ExpressionSource
{
    /**
     * Gets a value for a provided Expression.
     *
     * @param expression the expression to attempt to get a value for.
     * @return the value for the expression, or null if no value found.
     */
    String getExpressionValue( String expression );
}