1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/protocol/UriPatternMatcher.java $
3 * $Revision: 630662 $
4 * $Date: 2008-02-24 11:40:51 -0800 (Sun, 24 Feb 2008) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31
32package org.apache.http.protocol;
33
34import java.util.HashMap;
35import java.util.Iterator;
36import java.util.Map;
37
38/**
39 * Maintains a map of objects keyed by a request URI pattern.
40 * Instances can be looked up by request URI.<br/>
41 * Patterns may have three formats:
42 * <ul>
43 *   <li><code>*</code></li>
44 *   <li><code>*&lt;uri&gt;</code></li>
45 *   <li><code>&lt;uri&gt;*</code></li>
46 * </ul>
47 *
48 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
49 *
50 * @version $Revision: 630662 $
51 */
52public class UriPatternMatcher {
53
54    private final Map handlerMap;
55
56    public UriPatternMatcher() {
57        super();
58        this.handlerMap = new HashMap();
59    }
60
61    public void register(final String pattern, final Object handler) {
62        if (pattern == null) {
63            throw new IllegalArgumentException("URI request pattern may not be null");
64        }
65        if (handler == null) {
66            throw new IllegalArgumentException("HTTP request handelr may not be null");
67        }
68        this.handlerMap.put(pattern, handler);
69    }
70
71    public void unregister(final String pattern) {
72        if (pattern == null) {
73            return;
74        }
75        this.handlerMap.remove(pattern);
76    }
77
78    public void setHandlers(final Map map) {
79        if (map == null) {
80            throw new IllegalArgumentException("Map of handlers may not be null");
81        }
82        this.handlerMap.clear();
83        this.handlerMap.putAll(map);
84    }
85
86    public Object lookup(String requestURI) {
87        if (requestURI == null) {
88            throw new IllegalArgumentException("Request URI may not be null");
89        }
90        //Strip away the query part part if found
91        int index = requestURI.indexOf("?");
92        if (index != -1) {
93            requestURI = requestURI.substring(0, index);
94        }
95
96        // direct match?
97        Object handler = this.handlerMap.get(requestURI);
98        if (handler == null) {
99            // pattern match?
100            String bestMatch = null;
101            for (Iterator it = this.handlerMap.keySet().iterator(); it.hasNext();) {
102                String pattern = (String) it.next();
103                if (matchUriRequestPattern(pattern, requestURI)) {
104                    // we have a match. is it any better?
105                    if (bestMatch == null
106                            || (bestMatch.length() < pattern.length())
107                            || (bestMatch.length() == pattern.length() && pattern.endsWith("*"))) {
108                        handler = this.handlerMap.get(pattern);
109                        bestMatch = pattern;
110                    }
111                }
112            }
113        }
114        return handler;
115    }
116
117    protected boolean matchUriRequestPattern(final String pattern, final String requestUri) {
118        if (pattern.equals("*")) {
119            return true;
120        } else {
121            return
122            (pattern.endsWith("*") && requestUri.startsWith(pattern.substring(0, pattern.length() - 1))) ||
123            (pattern.startsWith("*") && requestUri.endsWith(pattern.substring(1, pattern.length())));
124        }
125    }
126
127}
128