    001    /* $Id: VariableExpander.java 471661 2006-11-06 08:09:25Z skitching $
    002     *
    003     * Licensed to the Apache Software Foundation (ASF) under one or more
    004     * contributor license agreements.  See the NOTICE file distributed with
    005     * this work for additional information regarding copyright ownership.
    006     * The ASF licenses this file to You under the Apache License, Version 2.0
    007     * (the "License"); you may not use this file except in compliance with
    008     * the License.  You may obtain a copy of the License at
    009     *
    010     *      http://www.apache.org/licenses/LICENSE-2.0
    011     *
    012     * Unless required by applicable law or agreed to in writing, software
    013     * distributed under the License is distributed on an "AS IS" BASIS,
    014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    015     * See the License for the specific language governing permissions and
    016     * limitations under the License.
    017     */
    018
    019
    020    package org.apache.commons.digester.substitution;
    021
    022    /**
    023     * <p>An Interface describing a class capable of expanding strings which
    024     * may contain variable references. The exact syntax of the "reference",
    025     * and the mechanism for determining the corresponding value to be used
    026     * is up to the concrete implementation.</p>
    027     *
    028     * @since 1.6
    029     */
    030    public interface VariableExpander {
    031        /**
    032         * Return the input string with any variables replaced by their
    033         * corresponding value. If there are no variables in the string,
    034         * then the input parameter is returned unaltered.
    035         */
    036        public String expand(String param);
    037    }
    038