package org.apache.commons.digester3.substitution;

/*
 * 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.
 */

/**
 * <p>
 * An Interface describing a class capable of expanding strings which may contain variable references. The exact syntax
 * of the "reference", and the mechanism for determining the corresponding value to be used is up to the concrete
 * implementation.
 * </p>
 * 
 * @since 1.6
 */
public interface VariableExpander
{

    /**
     * Return the input string with any variables replaced by their corresponding value. If there are no variables in
     * the string, then the input parameter is returned unaltered.
     *
     * @param param the string containing variables to be replaced.
     * @return the input string with any variables replaced by their corresponding value.
     */
    String expand( String param );

}