001package org.apache.commons.digester3.substitution;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022/**
023 * <p>
024 * An Interface describing a class capable of expanding strings which may contain variable references. The exact syntax
025 * of the "reference", and the mechanism for determining the corresponding value to be used is up to the concrete
026 * implementation.
027 * </p>
028 * 
029 * @since 1.6
030 */
031public interface VariableExpander
032{
033
034    /**
035     * Return the input string with any variables replaced by their corresponding value. If there are no variables in
036     * the string, then the input parameter is returned unaltered.
037     *
038     * @param param the string containing variables to be replaced.
039     * @return the input string with any variables replaced by their corresponding value.
040     */
041    String expand( String param );
042
043}