1 /*
2 * ====================================================================
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing,
14 * software distributed under the License is distributed on an
15 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16 * KIND, either express or implied. See the License for the
17 * specific language governing permissions and limitations
18 * under the License.
19 * ====================================================================
20 *
21 * This software consists of voluntary contributions made by many
22 * individuals on behalf of the Apache Software Foundation. For more
23 * information on the Apache Software Foundation, please see
24 * <http://www.apache.org/>.
25 *
26 */
27
28 package org.apache.hc.core5.http.protocol;
29
30 import java.util.HashSet;
31 import java.util.LinkedHashMap;
32 import java.util.Map;
33 import java.util.Map.Entry;
34 import java.util.Set;
35 import java.util.concurrent.locks.ReentrantLock;
36
37 import org.apache.hc.core5.annotation.Contract;
38 import org.apache.hc.core5.annotation.ThreadingBehavior;
39 import org.apache.hc.core5.util.Args;
40
41 /**
42 * Maintains a map of objects keyed by a request URI pattern.
43 * <p>
44 * Patterns may have three formats:
45 * </p>
46 * <ul>
47 * <li>{@code *}</li>
48 * <li>{@code *<uri>}</li>
49 * <li>{@code <uri>*}</li>
50 * </ul>
51 * <p>
52 * This class can be used to resolve an object matching a particular request
53 * URI.
54 * </p>
55 *
56 * @param <T> The type of registered objects.
57 * @since 4.0
58 */
59 @Contract(threading = ThreadingBehavior.SAFE)
60 public class UriPatternMatcher<T> implements LookupRegistry<T> {
61
62 private final Map<String, T> map;
63
64 private final ReentrantLock lock;
65
66 public UriPatternMatcher() {
67 super();
68 this.map = new LinkedHashMap<>();
69 this.lock = new ReentrantLock();
70 }
71
72 /**
73 * Returns a {@link Set} view of the mappings contained in this matcher.
74 *
75 * @return a set view of the mappings contained in this matcher.
76 *
77 * @see Map#entrySet()
78 * @since 4.4.9
79 */
80 public Set<Entry<String, T>> entrySet() {
81 lock.lock();
82 try {
83 return new HashSet<>(map.entrySet());
84 } finally {
85 lock.unlock();
86 }
87 }
88
89 /**
90 * Registers the given object for URIs matching the given pattern.
91 *
92 * @param pattern
93 * the pattern to register the handler for.
94 * @param obj
95 * the object.
96 */
97 @Override
98 public void register(final String pattern, final T obj) {
99 lock.lock();
100 try {
101 Args.notNull(pattern, "URI request pattern");
102 this.map.put(pattern, obj);
103 } finally {
104 lock.unlock();
105 }
106 }
107
108 /**
109 * Removes registered object, if exists, for the given pattern.
110 *
111 * @param pattern
112 * the pattern to unregister.
113 */
114 @Override
115 public void unregister(final String pattern) {
116 lock.lock();
117 try {
118 if (pattern == null) {
119 return;
120 }
121 this.map.remove(pattern);
122 } finally {
123 lock.unlock();
124 }
125 }
126
127 /**
128 * Looks up an object matching the given request path.
129 *
130 * @param path
131 * the request path
132 * @return object or {@code null} if no match is found.
133 */
134 @Override
135 public T lookup(final String path) {
136 lock.lock();
137 try {
138 Args.notNull(path, "Request path");
139 // direct match?
140 T obj = this.map.get(path);
141 if (obj == null) {
142 // pattern match?
143 String bestMatch = null;
144 for (final String pattern : this.map.keySet()) {
145 if (matchUriRequestPattern(pattern, path)) {
146 // we have a match. is it any better?
147 if (bestMatch == null || (bestMatch.length() < pattern.length())
148 || (bestMatch.length() == pattern.length() && pattern.endsWith("*"))) {
149 obj = this.map.get(pattern);
150 bestMatch = pattern;
151 }
152 }
153 }
154 }
155 return obj;
156 } finally {
157 lock.unlock();
158 }
159 }
160
161 /**
162 * Tests if the given request path matches the given pattern.
163 *
164 * @param pattern
165 * the pattern
166 * @param path
167 * the request path
168 * @return {@code true} if the request URI matches the pattern, {@code false} otherwise.
169 */
170 protected boolean matchUriRequestPattern(final String pattern, final String path) {
171 if (pattern.equals("*")) {
172 return true;
173 }
174 return (pattern.endsWith("*") && path.startsWith(pattern.substring(0, pattern.length() - 1)))
175 || (pattern.startsWith("*") && path.endsWith(pattern.substring(1)));
176 }
177
178 @Override
179 public String toString() {
180 return this.map.toString();
181 }
182
183 }