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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  
18  package org.apache.commons.configuration;
19  
20  import java.util.ArrayList;
21  import java.util.Iterator;
22  import java.util.List;
23  import java.util.Map;
24  import java.util.Properties;
25  
26  import org.apache.commons.collections.ExtendedProperties;
27  import org.apache.commons.lang.StringUtils;
28  
29  /**
30   * Configuration converter. Helper class to convert between Configuration,
31   * ExtendedProperties and standard Properties.
32   *
33   * @author <a href="mailto:mpoeschl@marmot.at">Martin Poeschl</a>
34   * @version $Id: ConfigurationConverter.java 1208788 2011-11-30 21:15:37Z oheger $
35   */
36  public final class ConfigurationConverter
37  {
38      /**
39       * Private constructor prevents instances from being created.
40       */
41      private ConfigurationConverter()
42      {
43          // to prevent instanciation...
44      }
45  
46      /**
47       * Convert a ExtendedProperties class into a Configuration class.
48       *
49       * @param eprops ExtendedProperties object to convert
50       * @return Configuration created from the ExtendedProperties
51       */
52      public static Configuration getConfiguration(ExtendedProperties eprops)
53      {
54          return new MapConfiguration(eprops);
55      }
56  
57      /**
58       * Convert a standard Properties class into a configuration class.
59       *
60       * @param props properties object to convert
61       * @return Configuration configuration created from the Properties
62       */
63      public static Configuration getConfiguration(Properties props)
64      {
65          return new MapConfiguration(props);
66      }
67  
68      /**
69       * Convert a Configuration class into a ExtendedProperties class.
70       *
71       * @param config Configuration object to convert
72       * @return ExtendedProperties created from the Configuration
73       */
74      public static ExtendedProperties getExtendedProperties(Configuration config)
75      {
76          ExtendedProperties props = new ExtendedProperties();
77  
78          for (Iterator<String> keys = config.getKeys(); keys.hasNext();)
79          {
80              String key = keys.next();
81              Object property = config.getProperty(key);
82  
83              // turn lists into vectors
84              if (property instanceof List)
85              {
86                  property = new ArrayList<Object>((List<?>) property);
87              }
88  
89              props.setProperty(key, property);
90          }
91  
92          return props;
93      }
94  
95      /**
96       * Convert a Configuration class into a Properties class. List properties
97       * are joined into a string using the delimiter of the configuration if it
98       * extends AbstractConfiguration, and a comma otherwise.
99       *
100      * @param config Configuration object to convert
101      * @return Properties created from the Configuration
102      */
103     public static Properties getProperties(Configuration config)
104     {
105         Properties props = new Properties();
106 
107         char delimiter = (config instanceof AbstractConfiguration)
108             ? ((AbstractConfiguration) config).getListDelimiter() : ',';
109 
110         for (Iterator<String> keys = config.getKeys(); keys.hasNext();)
111         {
112             String key = keys.next();
113             List<Object> list = config.getList(key);
114 
115             // turn the list into a string
116             props.setProperty(key, StringUtils.join(list.iterator(), delimiter));
117         }
118 
119         return props;
120     }
121 
122     /**
123      * Convert a Configuration class into a Map class.
124      *
125      * @param config Configuration object to convert
126      * @return Map created from the Configuration
127      */
128     public static Map<Object, Object> getMap(Configuration config)
129     {
130         return new ConfigurationMap(config);
131     }
132 
133 }