HardURLConverterChainUtil


1   /*
2    * Coefficient - facilitates project based collaboration
3    * Copyright (C) 2003, Dylan Etkin, CSIR icomtek
4    * PO Box 395
5    * Pretoria 0001, RSA
6    * This library is free software; you can redistribute it and/or
7    * modify it under the terms of the GNU Lesser General Public
8    * License as published by the Free Software Foundation; either
9    * version 2.1 of the License, or (at your option) any later version.
10   * This library is distributed in the hope that it will be useful,
11   * but WITHOUT ANY WARRANTY; without even the implied warranty of
12   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   * Lesser General Public License for more details.
14   *
15   * You should have received a copy of the GNU Lesser General Public
16   * License along with this library; if not, write to the Free Software
17   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18   */
19  
20  package za.org.coefficient.util.common;
21  
22  import za.org.coefficient.core.HardURLConverter;
23  
24  /**
25   *
26   * @author <a HREF="mailto:detkin@csir.co.za">Dylan Etkin</a>
27   */
28  public class HardURLConverterChainUtil {
29  
30      //~ Instance fields ========================================================
31  
32      private static HardURLConverter converter;
33  
34      //~ Methods ================================================================
35  
36      /**
37       * This method is used to register a new URL converter into the chain.
38       *
39       * @param val is the implementation of HardURLConverter to add to the 
40       * chain.
41       */
42      public static void addConverter(HardURLConverter val) {
43          if (val == null) {
44              throw new IllegalArgumentException  ("Cannot add a null URL converter");
45          }
46          if (converter == null) {
47              converter = val;
48          } else {
49              converter.append(val);
50          }
51      }
52  
53      /**
54       * Will pass the url throught the registered URL converters returing a
55       * new converted URL if one of the converters could handle the url.
56       *
57       * @param url is the URL that came in the request
58       * @return is the URL that should be redirected to, null if none of the
59       * registered converters could handle the URL.
60       */
61      public static String   execute(String   url) {
62          String   newURL = null;
63          try {
64              if (converter != null) {
65                  newURL = converter.invoke(url);
66              }
67          } catch (Exception   e) {
68              e.printStackTrace();
69          }
70          return newURL;
71      }
72  }
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