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.beanutils2.converters;
18
19 /**
20 * {@link org.apache.commons.beanutils2.Converter} implementation that handles conversion to and from <strong>java.lang.Enum</strong> objects.
21 * <p>
22 * Can be configured to either return a <em>default value</em> or throw a {@code ConversionException} if a conversion error occurs.
23 * </p>
24 *
25 * @param <E> The enum type subclass
26 * @since 2.0
27 * @see Enum
28 */
29 public final class EnumConverter<E extends Enum<E>> extends AbstractConverter<Enum<E>> {
30
31 /**
32 * Constructs a <strong>java.lang.Enum</strong> <em>Converter</em> that throws a {@code ConversionException} if an error occurs.
33 */
34 public EnumConverter() {
35 }
36
37 /**
38 * Constructs a <strong>java.lang.Enum</strong> <em>Converter</em> that returns a default value if an error occurs.
39 *
40 * @param defaultValue The default value to be returned if the value to be converted is missing or an error occurs converting the value.
41 */
42 public EnumConverter(final Enum<E> defaultValue) {
43 super(defaultValue);
44 }
45
46 /**
47 * <p>
48 * Converts a java.lang.Enum or object into a String.
49 * </p>
50 *
51 * @param <R> Target type of the conversion.
52 * @param type Data type to which this value should be converted.
53 * @param value The input value to be converted.
54 * @return The converted value.
55 * @throws Throwable if an error occurs converting to the specified type
56 * @since 2.0
57 */
58 @SuppressWarnings({ "rawtypes" })
59 @Override
60 protected <R> R convertToType(final Class<R> type, final Object value) throws Throwable {
61 if (Enum.class.isAssignableFrom(type)) {
62 final String enumValue = String.valueOf(value);
63 final R[] constants = type.getEnumConstants();
64 if (constants == null) {
65 throw conversionException(type, value);
66 }
67 for (final R candidate : constants) {
68 if (((Enum) candidate).name().equalsIgnoreCase(enumValue)) {
69 return candidate;
70 }
71 }
72 }
73
74 throw conversionException(type, value);
75 }
76
77 /**
78 * Gets the default type this {@code Converter} handles.
79 *
80 * @return The default type this {@code Converter} handles.
81 * @since 2.0
82 */
83 @SuppressWarnings({ "unchecked", "rawtypes" })
84 @Override
85 protected Class<Enum<E>> getDefaultType() {
86 return (Class) Enum.class;
87 }
88
89 }