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
36 import org.apache.hc.core5.annotation.Contract;
37 import org.apache.hc.core5.annotation.ThreadingBehavior;
38 import org.apache.hc.core5.util.Args;
39
40 /**
41 * Maintains a map of objects keyed by a request URI pattern.
42 * <p>
43 * Patterns may have three formats:
44 * </p>
45 * <ul>
46 * <li>{@code *}</li>
47 * <li>{@code *<uri>}</li>
48 * <li>{@code <uri>*}</li>
49 * </ul>
50 * <p>
51 * This class can be used to resolve an object matching a particular request
52 * URI.
53 * </p>
54 *
55 * @param <T> The type of registered objects.
56 * @since 4.0
57 */
58 @Contract(threading = ThreadingBehavior.SAFE)
59 public class UriPatternMatcher<T> implements LookupRegistry<T> {
60
61 private final Map<String, T> map;
62
63 public UriPatternMatcher() {
64 super();
65 this.map = new LinkedHashMap<>();
66 }
67
68 /**
69 * Returns a {@link Set} view of the mappings contained in this matcher.
70 *
71 * @return a set view of the mappings contained in this matcher.
72 *
73 * @see Map#entrySet()
74 * @since 4.4.9
75 */
76 public synchronized Set<Entry<String, T>> entrySet() {
77 return new HashSet<>(map.entrySet());
78 }
79
80 /**
81 * Registers the given object for URIs matching the given pattern.
82 *
83 * @param pattern
84 * the pattern to register the handler for.
85 * @param obj
86 * the object.
87 */
88 @Override
89 public synchronized void register(final String pattern, final T obj) {
90 Args.notNull(pattern, "URI request pattern");
91 this.map.put(pattern, obj);
92 }
93
94 /**
95 * Removes registered object, if exists, for the given pattern.
96 *
97 * @param pattern
98 * the pattern to unregister.
99 */
100 @Override
101 public synchronized void unregister(final String pattern) {
102 if (pattern == null) {
103 return;
104 }
105 this.map.remove(pattern);
106 }
107
108 /**
109 * Looks up an object matching the given request path.
110 *
111 * @param path
112 * the request path
113 * @return object or {@code null} if no match is found.
114 */
115 @Override
116 public synchronized T lookup(final String path) {
117 Args.notNull(path, "Request path");
118 // direct match?
119 T obj = this.map.get(path);
120 if (obj == null) {
121 // pattern match?
122 String bestMatch = null;
123 for (final String pattern : this.map.keySet()) {
124 if (matchUriRequestPattern(pattern, path)) {
125 // we have a match. is it any better?
126 if (bestMatch == null || (bestMatch.length() < pattern.length())
127 || (bestMatch.length() == pattern.length() && pattern.endsWith("*"))) {
128 obj = this.map.get(pattern);
129 bestMatch = pattern;
130 }
131 }
132 }
133 }
134 return obj;
135 }
136
137 /**
138 * Tests if the given request path matches the given pattern.
139 *
140 * @param pattern
141 * the pattern
142 * @param path
143 * the request path
144 * @return {@code true} if the request URI matches the pattern, {@code false} otherwise.
145 */
146 protected boolean matchUriRequestPattern(final String pattern, final String path) {
147 if (pattern.equals("*")) {
148 return true;
149 }
150 return (pattern.endsWith("*") && path.startsWith(pattern.substring(0, pattern.length() - 1)))
151 || (pattern.startsWith("*") && path.endsWith(pattern.substring(1)));
152 }
153
154 @Override
155 public String toString() {
156 return this.map.toString();
157 }
158
159 }