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1   package org.apache.velocity.runtime.resource.loader;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.    
20   */
21  
22  import org.apache.velocity.runtime.RuntimeServices;
23  import org.apache.velocity.util.ClassUtils;
24  import org.apache.velocity.util.StringUtils;
25  
26  /**
27   * Factory to grab a template loader.
28   *
29   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
30   * @version $Id: ResourceLoaderFactory.java 463298 2006-10-12 16:10:32Z henning $
31   */
32  public class ResourceLoaderFactory
33  {
34      /**
35       * Gets the loader specified in the configuration file.
36       * @param rs
37       * @param loaderClassName
38       * @return TemplateLoader
39       * @throws Exception
40       */
41      public static ResourceLoader getLoader(RuntimeServices rs, String loaderClassName)
42       throws Exception
43      {
44          ResourceLoader loader = null;
45  
46          try
47          {
48              loader = (ResourceLoader) ClassUtils.getNewInstance( loaderClassName );
49  
50              rs.getLog().debug("ResourceLoader instantiated: "
51                                + loader.getClass().getName());
52  
53              return loader;
54          }
55          // The ugly three strike again: ClassNotFoundException,IllegalAccessException,InstantiationException
56          catch(Exception e)
57          {
58              rs.getLog().error("Problem instantiating the template loader.\n" +
59                            "Look at your properties file and make sure the\n" +
60                            "name of the template loader is correct. Here is the\n" +
61                            "error:", e);
62  
63              throw new Exception("Problem initializing template loader: " + loaderClassName +
64              "\nError is: " + StringUtils.stackTrace(e));
65          }
66      }
67  }