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1   /*
2    * Copyright (c) 2003, Henri Yandell
3    * All rights reserved.
4    * 
5    * Redistribution and use in source and binary forms, with or 
6    * without modification, are permitted provided that the 
7    * following conditions are met:
8    * 
9    * + Redistributions of source code must retain the above copyright notice, 
10   *   this list of conditions and the following disclaimer.
11   * 
12   * + Redistributions in binary form must reproduce the above copyright notice, 
13   *   this list of conditions and the following disclaimer in the documentation 
14   *   and/or other materials provided with the distribution.
15   * 
16   * + Neither the name of OSJava nor the names of its contributors 
17   *   may be used to endorse or promote products derived from this software 
18   *   without specific prior written permission.
19   * 
20   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
21   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
22   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
23   * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
24   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
25   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
26   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
27   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
28   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
29   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
30   * POSSIBILITY OF SUCH DAMAGE.
31   */
32  package org.osjava.norbert;
33  
34  import java.util.ArrayList;
35  import java.util.Iterator;
36  import java.util.List;
37  
38  /***
39   * Contains a series of Rules. It then runs a path against these 
40   * to decide if it is allowed or not. 
41   */
42   // TODO: Make this package private?
43  class RulesEngine {
44  
45      private List rules;
46  
47      public RulesEngine() {
48          this.rules = new ArrayList();
49      }
50  
51      public void allowPath(String path) {
52          add( new AllowedRule(path) );
53      }
54  
55      public void disallowPath(String path) {
56          add( new DisallowedRule(path) );
57      }
58  
59      public void add(Rule rule) {
60          this.rules.add(rule);
61      }
62  
63      /***
64       * Run each Rule in series on the path. 
65       * If a Rule returns a Boolean, return that.
66       * When no more rules are left, return null to indicate there were 
67       * no rules for this path.. 
68       */
69      public Boolean isAllowed(String path) {
70  
71          Iterator iterator = this.rules.iterator();
72          while(iterator.hasNext()) {
73              Rule rule = (Rule)iterator.next();
74              Boolean test = rule.isAllowed(path);
75              if(test != null) {
76                  return test;
77              }
78          }
79  
80          return null;
81      }
82  
83      public boolean isEmpty() {
84          return this.rules.isEmpty();
85      }
86  
87      public String toString() {
88          return "RulesEngine: " + this.rules;
89      }
90  
91  }