001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.scxml.env;
018    
019    import java.io.Serializable;
020    import java.net.MalformedURLException;
021    import java.net.URL;
022    
023    import org.apache.commons.logging.Log;
024    import org.apache.commons.logging.LogFactory;
025    import org.apache.commons.scxml.PathResolver;
026    
027    /**
028     * A PathResolver implementation that resolves against a base URL.
029     *
030     * @see org.apache.commons.scxml.PathResolver
031     */
032    public class URLResolver implements PathResolver, Serializable {
033    
034        /** Serial version UID. */
035        private static final long serialVersionUID = 1L;
036    
037        /** Implementation independent log category. */
038        private Log log = LogFactory.getLog(PathResolver.class);
039    
040        /** The base URL to resolve against. */
041        private URL baseURL = null;
042    
043        /**
044         * Constructor.
045         *
046         * @param baseURL The base URL to resolve against
047         */
048        public URLResolver(final URL baseURL) {
049            this.baseURL = baseURL;
050        }
051    
052        /**
053         * Uses URL(URL, String) constructor to combine URL's.
054         * @see org.apache.commons.scxml.PathResolver#resolvePath(java.lang.String)
055         */
056        public String resolvePath(final String ctxPath) {
057            URL combined;
058            try {
059                combined = new URL(baseURL, ctxPath);
060                return combined.toString();
061            } catch (MalformedURLException e) {
062                log.error("Malformed URL", e);
063            }
064            return null;
065        }
066    
067        /**
068         * @see org.apache.commons.scxml.PathResolver#getResolver(java.lang.String)
069         */
070        public PathResolver getResolver(final String ctxPath) {
071            URL combined;
072            try {
073                combined = new URL(baseURL, ctxPath);
074                return new URLResolver(combined);
075            } catch (MalformedURLException e) {
076                log.error("Malformed URL", e);
077            }
078            return null;
079        }
080    
081    }
082