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 * https://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 * <p>
28 * Public access is through {@link StringLookupFactory}.
29 * </p>
30 *
31 * @see StringLookupFactory
32 * @see URLEncoder
33 * @since 1.5
34 */
35 final class UrlDecoderStringLookup extends AbstractStringLookup {
36
37 /**
38 * Defines the singleton for this class.
39 */
40 static final UrlDecoderStringLookup INSTANCE = new UrlDecoderStringLookup();
41
42 /**
43 * Constructs a new instance.
44 */
45 private UrlDecoderStringLookup() {
46 // empty
47 }
48
49 String decode(final String key, final String enc) throws UnsupportedEncodingException {
50 return URLDecoder.decode(key, enc);
51 }
52
53 @Override
54 public String lookup(final String key) {
55 if (key == null) {
56 return null;
57 }
58 final String enc = StandardCharsets.UTF_8.name();
59 try {
60 return decode(key, enc);
61 } catch (final UnsupportedEncodingException e) {
62 // Can't happen since UTF-8 is required by the Java specification.
63 throw IllegalArgumentExceptions.format(e, "%s: source=%s, encoding=%s", e, key, enc);
64 }
65 }
66
67 }