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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.tools;
18  
19  import java.util.Properties;
20  
21  import org.apache.commons.discovery.resource.ClassLoaders;
22  
23  
24  /***
25   * Holder for a default class.
26   * 
27   * Class may be specified by name (String) or class (Class).
28   * Using the holder complicates the users job, but minimized # of API's.
29   * 
30   * @author Richard A. Sitze
31   */
32  public class PropertiesHolder {
33      private Properties   properties;
34      private final String propertiesFileName;
35      
36      public PropertiesHolder(Properties properties) {
37          this.properties = properties;
38          this.propertiesFileName = null;
39      }
40      
41      public PropertiesHolder(String propertiesFileName) {
42          this.properties = null;
43          this.propertiesFileName = propertiesFileName;
44      }
45  
46      /***
47       * @param spi Optional SPI (may be null).
48       *            If provided, an attempt is made to load the
49       *            property file as-per Class.getResource().
50       * 
51       * @param loaders Used only if properties need to be loaded.
52       * 
53       * @return Properties.  Load the properties if necessary.
54       */
55      public Properties getProperties(SPInterface spi, ClassLoaders loaders) {
56          if (properties == null) {
57              properties = ResourceUtils.loadProperties(spi.getSPClass(), getPropertiesFileName(), loaders);
58          }
59          return properties;
60      }
61  
62      public String getPropertiesFileName() {
63          return propertiesFileName;
64      }
65  }