1 : <?php
2 : /**
3 : * Licensed to the Apache Software Foundation (ASF) under one or more
4 : * contributor license agreements. See the NOTICE file distributed with
5 : * this work for additional information regarding copyright ownership.
6 : * The ASF licenses this file to You under the Apache License, Version 2.0
7 : * (the "License"); you may not use this file except in compliance with
8 : * the License. You may obtain a copy of the License at
9 : *
10 : * http://www.apache.org/licenses/LICENSE-2.0
11 : *
12 : * Unless required by applicable law or agreed to in writing, software
13 : * distributed under the License is distributed on an "AS IS" BASIS,
14 : * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 : * See the License for the specific language governing permissions and
16 : * limitations under the License.
17 : *
18 : * @package log4php
19 : */
20 :
21 : /**
22 : * Users should extend this class to implement customized logging
23 : * event filtering. Note that {@link LoggerCategory} and {@link LoggerAppender},
24 : * the parent class of all standard
25 : * appenders, have built-in filtering rules. It is suggested that you
26 : * first use and understand the built-in rules before rushing to write
27 : * your own custom filters.
28 : *
29 : * <p>This abstract class assumes and also imposes that filters be
30 : * organized in a linear chain. The {@link #decide
31 : * decide(LoggerLoggingEvent)} method of each filter is called sequentially,
32 : * in the order of their addition to the chain.
33 : *
34 : * <p>The {@link decide()} method must return one
35 : * of the integer constants {@link LoggerFilter::DENY},
36 : * {@link LoggerFilter::NEUTRAL} or {@link LoggerFilter::ACCEPT}.
37 : *
38 : * <p>If the value {@link LoggerFilter::DENY} is returned, then the log event is
39 : * dropped immediately without consulting with the remaining
40 : * filters.
41 : *
42 : * <p>If the value {@link LoggerFilter::NEUTRAL} is returned, then the next filter
43 : * in the chain is consulted. If there are no more filters in the
44 : * chain, then the log event is logged. Thus, in the presence of no
45 : * filters, the default behaviour is to log all logging events.
46 : *
47 : * <p>If the value {@link LoggerFilter::ACCEPT} is returned, then the log
48 : * event is logged without consulting the remaining filters.
49 : *
50 : * <p>The philosophy of log4php filters is largely inspired from the
51 : * Linux ipchains.
52 : *
53 : * @version $Revision: 1213283 $
54 : * @package log4php
55 : */
56 : abstract class LoggerFilter extends LoggerConfigurable {
57 :
58 : /**
59 : * The log event must be logged immediately without consulting with
60 : * the remaining filters, if any, in the chain.
61 : */
62 : const ACCEPT = 1;
63 :
64 : /**
65 : * This filter is neutral with respect to the log event. The
66 : * remaining filters, if any, should be consulted for a final decision.
67 : */
68 : const NEUTRAL = 0;
69 :
70 : /**
71 : * The log event must be dropped immediately without consulting
72 : * with the remaining filters, if any, in the chain.
73 : */
74 : const DENY = -1;
75 :
76 : /**
77 : * @var LoggerFilter Points to the next {@link LoggerFilter} in the filter chain.
78 : */
79 : protected $next;
80 :
81 : /**
82 : * Usually filters options become active when set. We provide a
83 : * default do-nothing implementation for convenience.
84 : */
85 : public function activateOptions() {
86 5 : }
87 :
88 : /**
89 : * Decide what to do.
90 : * <p>If the decision is {@link LoggerFilter::DENY}, then the event will be
91 : * dropped. If the decision is {@link LoggerFilter::NEUTRAL}, then the next
92 : * filter, if any, will be invoked. If the decision is {@link LoggerFilter::ACCEPT} then
93 : * the event will be logged without consulting with other filters in
94 : * the chain.
95 : *
96 : * @param LoggerLoggingEvent $event The {@link LoggerLoggingEvent} to decide upon.
97 : * @return integer {@link LoggerFilter::NEUTRAL} or {@link LoggerFilter::DENY}|{@link LoggerFilter::ACCEPT}
98 : */
99 : public function decide(LoggerLoggingEvent $event) {
100 1 : return self::NEUTRAL;
101 : }
102 :
103 : /**
104 : * Adds a new filter to the filter chain this filter is a part of.
105 : * If this filter has already and follow up filter, the param filter
106 : * is passed on until it is the last filter in chain.
107 : *
108 : * @param $filter - the filter to add to this chain
109 : */
110 : public function addNext($filter) {
111 2 : if($this->next !== null) {
112 0 : $this->next->addNext($filter);
113 0 : } else {
114 2 : $this->next = $filter;
115 : }
116 2 : }
117 :
118 : /**
119 : * Returns the next filter in this chain
120 : * @return the next filter
121 : */
122 : public function getNext() {
123 4 : return $this->next;
124 : }
125 :
126 : }
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