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.servlet;
018
019 import javax.servlet.ServletContext;
020
021 import org.apache.commons.scxml.PathResolver;
022
023 /**
024 * A wrapper around ServletContext that implements PathResolver.
025 *
026 * @see org.apache.commons.scxml.PathResolver
027 */
028 public class ServletContextResolver implements PathResolver {
029
030 /** Cannot accept a null ServletContext, it will just throw
031 * NullPointerException down the road. */
032 private static final String ERR_SERVLET_CTX_NULL =
033 "ServletContextResolver cannot be instantiated with a null"
034 + " ServletContext";
035
036 /** The SevletContext we will use to resolve paths. */
037 private ServletContext ctx = null;
038
039 /**
040 * Constructor.
041 *
042 * @param ctx The ServletContext instance for this web application.
043 */
044 public ServletContextResolver(final ServletContext ctx) {
045 if (ctx == null) {
046 throw new IllegalArgumentException(ERR_SERVLET_CTX_NULL);
047 }
048 this.ctx = ctx;
049 }
050
051 /**
052 * Delegates to the underlying ServletContext's getRealPath(String).
053 *
054 * @param ctxPath context sensitive path, can be a relative URL
055 * @return resolved path (an absolute URL) or <code>null</code>
056 * @see org.apache.commons.scxml.PathResolver#resolvePath(java.lang.String)
057 */
058 public String resolvePath(final String ctxPath) {
059 return ctx.getRealPath(ctxPath);
060 }
061
062 /**
063 * Retrieve the PathResolver rooted at the given path.
064 *
065 * @param ctxPath context sensitive path, can be a relative URL
066 * @return returns a new resolver rooted at ctxPath
067 * @see org.apache.commons.scxml.PathResolver#getResolver(java.lang.String)
068 */
069 public PathResolver getResolver(final String ctxPath) {
070 return this;
071 }
072
073 }
074