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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.discovery.resource.names;
18  
19  import org.apache.commons.discovery.ResourceNameDiscover;
20  import org.apache.commons.discovery.ResourceNameIterator;
21  import org.apache.commons.discovery.log.DiscoveryLogFactory;
22  import org.apache.commons.logging.Log;
23  
24  
25  /***
26   * Recover resource name from System Properties.
27   * 
28   * @author Richard A. Sitze
29   */
30  public class DiscoverNamesInSystemProperties
31      extends ResourceNameDiscoverImpl
32      implements ResourceNameDiscover
33  {
34      private static Log log = DiscoveryLogFactory.newLog(DiscoverNamesInSystemProperties.class);
35      public static void setLog(Log _log) {
36          log = _log;
37      }
38      
39      /*** Construct a new resource discoverer
40       */
41      public DiscoverNamesInSystemProperties() {
42      }
43  
44      /***
45       * @return Enumeration of ResourceInfo
46       */
47      public ResourceNameIterator findResourceNames(final String resourceName) {
48          if (log.isDebugEnabled())
49              log.debug("find: resourceName='" + resourceName + "'");
50  
51          return new ResourceNameIterator() {
52              private String resource = System.getProperty(resourceName);
53              
54              public boolean hasNext() {
55                  return resource != null;
56              }
57              
58              public String nextResourceName() {
59                  String element = resource;
60                  resource = null;
61                  return element;
62              }
63          };
64      }
65  }