RegexLink


1   /*
2    * Copyright (c) 2002, Inversoft Corporation, All Rights Reserved
3    */
4   package com.inversoft.verge.mvc.controller.actionflow.config;
5   
6   
7   import java.util.regex.Matcher  ;
8   import java.util.regex.Pattern  ;
9   
10  import com.inversoft.util.StringTools;
11  
12  
13  /**
14   * This class describes a link between two Nodes that is
15   * are connected by a regular expression. This regex is used
16   * to match action names. The Node objects are responsible
17   * for implementing how these Links are stored and searched,
18   * but the matching logic is contained in this class. Currently,
19   * this class uses only Java 1.4 regex package for simplicity
20   * and future support, because we all know what happens to OS
21   * projects when Sun adds something new to the API :)
22   *
23   * @author  Brian Pontarelli
24   * @since   2.0
25   * @version 2.0
26   */
27  public class RegexLink extends BaseLink {
28  
29      private Pattern   regex;
30  
31  
32      /**
33       * Constructs a new RegexLink with the given regex, origin Node
34       * and destination Node.
35       */
36      public RegexLink(String   regex, Node origin, Node destination) {
37  
38          super(origin, destination);
39          if (StringTools.isEmpty(regex)) {
40              throw new IllegalArgumentException  ("The regex is empty or null");
41          }
42  
43          this.regex = Pattern.compile(regex);
44      }
45  
46  
47      /**
48       * Gets the regular expression pattern of this link
49       *
50       * @return Returns the pattern of this link
51       */
52      public Pattern   getRegex() {
53          return regex;
54      }
55      
56      /**
57       * Returns the value of the link which is the regex pattern.
58       * 
59       * @return  The value of the link
60       */
61      public String   getValue() {
62          return regex.pattern();
63      }
64      
65      /**
66       * Returns whether this Link accepts the given action. This returns true if
67       * the given action is equal to the action of this Link using the equals
68       * method of the String class.
69       *
70       * @param   action The action to check for acceptance
71       * @return  True if the given action equals the action of this Link
72       */
73      public boolean acceptAction(Object   action) {
74          assert (action instanceof String  ) : "action must be a String";
75          assert (!StringTools.isEmpty((String  ) action)) : "action can not be null or empty";
76  
77          Matcher   matcher = regex.matcher((String  ) action);
78          return matcher.matches();
79      }
80      
81      /**
82       * Returns a String representation of this link suitable for debugging
83       */
84      public String   toString() {
85          StringBuffer   buf = new StringBuffer  ();
86          buf.append(getOrigin().getName()).append(" --(").append(regex);
87          buf.append(")--> ").append(getDestination().getName());
88          return buf.toString();
89      }
90  }
91  
92
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