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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.beanutils.converters;
18  
19  /**
20   * {@link org.apache.commons.beanutils.Converter}
21   * implementation that converts an incoming
22   * object into a <code>java.lang.String</code> object.
23   * <p>
24   * Note that ConvertUtils really is designed to do string->object conversions,
25   * and offers very little support for object->string conversions. The
26   * ConvertUtils/ConvertUtilsBean methods only select a converter to apply
27   * based upon the target type being converted to, and generally assume that
28   * the input is a string (by calling its toString method if needed).
29   * <p>
30   * This class is therefore just a dummy converter that converts its input
31   * into a string by calling the input object's toString method and returning
32   * that value.
33   * <p>
34   * It is possible to replace this converter with something that has a big
35   * if/else statement that selects behaviour based on the real type of the
36   * object being converted (or possibly has a map of converters, and looks
37   * them up based on the class of the input object). However this is not part
38   * of the existing ConvertUtils framework.
39   *  
40   *
41   * @author Craig R. McClanahan
42   * @version $Revision: 690380 $ $Date: 2008-08-29 16:04:38 -0400 (Fri, 29 Aug 2008) $
43   * @since 1.3
44   */
45  public final class StringConverter extends AbstractConverter {
46  
47  
48      /**
49       * Construct a <b>java.lang.String</b> <i>Converter</i> that throws
50       * a <code>ConversionException</code> if an error occurs.
51       */
52      public StringConverter() {
53          super();
54      }
55  
56      /**
57       * Construct a <b>java.lang.String</b> <i>Converter</i> that returns
58       * a default value if an error occurs.
59       *
60       * @param defaultValue The default value to be returned
61       * if the value to be converted is missing or an error
62       * occurs converting the value.
63       */
64      public StringConverter(Object defaultValue) {
65          super(defaultValue);
66      }
67  
68      /**
69       * Return the default type this <code>Converter</code> handles.
70       *
71       * @return The default type this <code>Converter</code> handles.
72       * @since 1.8.0
73       */
74      protected Class getDefaultType() {
75          return String.class;
76      }
77  
78      /**
79       * Convert the specified input object into an output object of the
80       * specified type.
81       *
82       * @param type Data type to which this value should be converted.
83       * @param value The input value to be converted.
84       * @return The converted value.
85       * @throws Throwable if an error occurs converting to the specified type
86       * @since 1.8.0
87       */
88      protected Object convertToType(Class type, Object value) throws Throwable {
89          return value.toString();
90      }
91  
92  
93  }