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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.log4j.rule;
19  
20  import org.apache.log4j.spi.LoggingEvent;
21  
22  import java.util.HashMap;
23  import java.util.HashSet;
24  import java.util.Iterator;
25  import java.util.Map;
26  import java.util.Set;
27  import java.util.Stack;
28  
29  /***
30   * A Rule class implementing logical not.
31   *
32   * @author Scott Deboy (sdeboy@apache.org)
33   */
34  public class NotRule extends AbstractRule {
35      /***
36       * Serialization ID.
37       */
38    static final long serialVersionUID = -6827159473117969306L;
39      /***
40       * Enclosed rule.
41       */
42    private final Rule rule;
43  
44      /***
45       * Create new instance.
46       * @param rule enclosed rule.
47       */
48    private NotRule(final Rule rule) {
49      super();
50      this.rule = rule;
51    }
52  
53      /***
54       * Create new instance.
55       * @param rule enclosed rule.
56       * @return new rule.
57       */
58    public static Rule getRule(final Rule rule) {
59        return new NotRule(rule);
60    }
61  
62      /***
63       * Create new instance from top element of stack.
64       * @param stack stack
65       * @return new rule.
66       */
67    public static Rule getRule(final Stack stack) {
68        if (stack.size() < 1) {
69            throw new IllegalArgumentException(
70                    "Invalid NOT rule - expected one rule but received "
71                            + stack.size());
72        }
73        Object o1 = stack.pop();
74        if (o1 instanceof Rule) {
75          Rule p1 = (Rule) o1;
76          return new NotRule(p1);
77        }
78        throw new IllegalArgumentException(
79                "Invalid NOT rule: - expected rule but received " + o1);
80    }
81  
82      /*** {@inheritDoc} */
83    public boolean evaluate(final LoggingEvent event, Map matches) {
84      if (matches == null) {
85        return !(rule.evaluate(event, null));
86      }
87      Map tempMatches = new HashMap();
88      boolean result = !(rule.evaluate(event, tempMatches));
89      if (result) {
90          for (Iterator iter = tempMatches.entrySet().iterator();iter.hasNext();) {
91              Map.Entry entry = (Map.Entry)iter.next();
92              Object key = entry.getKey();
93              Set value = (Set)entry.getValue();
94              Set mainSet = (Set) matches.get(key);
95              if (mainSet == null) {
96                  mainSet = new HashSet();
97                  matches.put(key, mainSet);
98              }
99              mainSet.addAll(value);
100         }
101     }
102     return result;
103   }
104 }