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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.scxml.env.servlet;
18  
19  import javax.servlet.ServletContext;
20  
21  import org.apache.commons.scxml.PathResolver;
22  
23  /***
24   * A wrapper around ServletContext that implements PathResolver.
25   *
26   * @see org.apache.commons.scxml.PathResolver
27   */
28  public class ServletContextResolver implements PathResolver {
29  
30      /*** Cannot accept a null ServletContext, it will just throw
31       *  NullPointerException down the road. */
32      private static final String ERR_SERVLET_CTX_NULL =
33          "ServletContextResolver cannot be instantiated with a null"
34          + " ServletContext";
35  
36      /*** The SevletContext we will use to resolve paths. */
37      private ServletContext ctx = null;
38  
39      /***
40       * Constructor.
41       *
42       * @param ctx The ServletContext instance for this web application.
43       */
44      public ServletContextResolver(final ServletContext ctx) {
45          if (ctx == null) {
46              throw new IllegalArgumentException(ERR_SERVLET_CTX_NULL);
47          }
48          this.ctx = ctx;
49      }
50  
51      /***
52       * Delegates to the underlying ServletContext's getRealPath(String).
53       *
54       * @param ctxPath context sensitive path, can be a relative URL
55       * @return resolved path (an absolute URL) or <code>null</code>
56       * @see org.apache.commons.scxml.PathResolver#resolvePath(java.lang.String)
57       */
58      public String resolvePath(final String ctxPath) {
59          return ctx.getRealPath(ctxPath);
60      }
61  
62      /***
63       * Retrieve the PathResolver rooted at the given path.
64       *
65       * @param ctxPath context sensitive path, can be a relative URL
66       * @return returns a new resolver rooted at ctxPath
67       * @see org.apache.commons.scxml.PathResolver#getResolver(java.lang.String)
68       */
69      public PathResolver getResolver(final String ctxPath) {
70          return this;
71      }
72  
73  }
74