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.helpers;
19
20 import org.apache.log4j.spi.LoggingEvent;
21
22 /**
23
24 <p>PatternConverter is an abtract class that provides the
25 formatting functionality that derived classes need.
26
27 <p>Conversion specifiers in a conversion patterns are parsed to
28 individual PatternConverters. Each of which is responsible for
29 converting a logging event in a converter specific manner.
30
31 @author <a href="mailto:cakalijp@Maritz.com">James P. Cakalic</a>
32 @author Ceki Gülcü
33
34 @since 0.8.2
35 */
36 public abstract class PatternConverter {
37 public PatternConverter next;
38 int min = -1;
39 int max = 0x7FFFFFFF;
40 boolean leftAlign = false;
41
42 protected
43 PatternConverter() { }
44
45 protected
46 PatternConverter(FormattingInfo fi) {
47 min = fi.min;
48 max = fi.max;
49 leftAlign = fi.leftAlign;
50 }
51
52 /**
53 Derived pattern converters must override this method in order to
54 convert conversion specifiers in the correct way.
55 */
56 abstract
57 protected
58 String convert(LoggingEvent event);
59
60 /**
61 A template method for formatting in a converter specific way.
62 */
63 public
64 void format(StringBuffer sbuf, LoggingEvent e) {
65 String s = convert(e);
66
67 if(s == null) {
68 if(0 < min)
69 spacePad(sbuf, min);
70 return;
71 }
72
73 int len = s.length();
74
75 if(len > max)
76 sbuf.append(s.substring(len-max));
77 else if(len < min) {
78 if(leftAlign) {
79 sbuf.append(s);
80 spacePad(sbuf, min-len);
81 }
82 else {
83 spacePad(sbuf, min-len);
84 sbuf.append(s);
85 }
86 }
87 else
88 sbuf.append(s);
89 }
90
91 static String[] SPACES = {" ", " ", " ", " ", //1,2,4,8 spaces
92 " ", // 16 spaces
93 " " }; // 32 spaces
94
95 /**
96 Fast space padding method.
97 */
98 public
99 void spacePad(StringBuffer sbuf, int length) {
100 while(length >= 32) {
101 sbuf.append(SPACES[5]);
102 length -= 32;
103 }
104
105 for(int i = 4; i >= 0; i--) {
106 if((length & (1<<i)) != 0) {
107 sbuf.append(SPACES[i]);
108 }
109 }
110 }
111 }
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