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.text.lookup;
19
20 import java.io.UnsupportedEncodingException;
21 import java.net.URLDecoder;
22 import java.net.URLEncoder;
23 import java.nio.charset.StandardCharsets;
24
25 /**
26 * Decodes URL Strings using the UTF-8 encoding.
27 *
28 * @see URLEncoder
29 * @since 1.5
30 */
31 final class UrlDecoderStringLookup extends AbstractStringLookup {
32
33 /**
34 * Defines the singleton for this class.
35 */
36 static final UrlDecoderStringLookup INSTANCE = new UrlDecoderStringLookup();
37
38 /**
39 * Constructs a new instance.
40 */
41 private UrlDecoderStringLookup() {
42 // empty
43 }
44
45 String decode(final String key, final String enc) throws UnsupportedEncodingException {
46 return URLDecoder.decode(key, enc);
47 }
48
49 @Override
50 public String lookup(final String key) {
51 if (key == null) {
52 return null;
53 }
54 final String enc = StandardCharsets.UTF_8.name();
55 try {
56 return decode(key, enc);
57 } catch (final UnsupportedEncodingException e) {
58 // Can't happen since UTF-8 is required by the Java specification.
59 throw IllegalArgumentExceptions.format(e, "%s: source=%s, encoding=%s", e, key, enc);
60 }
61 }
62
63 }