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      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 
     32 package org.apache.http.protocol;
     33 
     34 import java.util.HashMap;
     35 import java.util.Iterator;
     36 import 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  */
     52 public 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