1 /*
2 * Copyright 2000-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26
27 package java.util.logging;
28
29 /**
30 * A Formatter provides support for formatting LogRecords.
31 * <p>
32 * Typically each logging Handler will have a Formatter associated
33 * with it. The Formatter takes a LogRecord and converts it to
34 * a string.
35 * <p>
36 * Some formatters (such as the XMLFormatter) need to wrap head
37 * and tail strings around a set of formatted records. The getHeader
38 * and getTail methods can be used to obtain these strings.
39 *
40 * @since 1.4
41 */
42
43 public abstract class Formatter {
44
45 /**
46 * Construct a new formatter.
47 */
48 protected Formatter() {
49 }
50
51 /**
52 * Format the given log record and return the formatted string.
53 * <p>
54 * The resulting formatted String will normally include a
55 * localized and formated version of the LogRecord's message field.
56 * It is recommended to use the {@link Formatter#formatMessage}
57 * convenience method to localize and format the message field.
58 *
59 * @param record the log record to be formatted.
60 * @return the formatted log record
61 */
62 public abstract String format(LogRecord record);
63
64
65 /**
66 * Return the header string for a set of formatted records.
67 * <p>
68 * This base class returns an empty string, but this may be
69 * overriden by subclasses.
70 *
71 * @param h The target handler (can be null)
72 * @return header string
73 */
74 public String getHead(Handler h) {
75 return "";
76 }
77
78 /**
79 * Return the tail string for a set of formatted records.
80 * <p>
81 * This base class returns an empty string, but this may be
82 * overriden by subclasses.
83 *
84 * @param h The target handler (can be null)
85 * @return tail string
86 */
87 public String getTail(Handler h) {
88 return "";
89 }
90
91
92 /**
93 * Localize and format the message string from a log record. This
94 * method is provided as a convenience for Formatter subclasses to
95 * use when they are performing formatting.
96 * <p>
97 * The message string is first localized to a format string using
98 * the record's ResourceBundle. (If there is no ResourceBundle,
99 * or if the message key is not found, then the key is used as the
100 * format string.) The format String uses java.text style
101 * formatting.
102 * <ul>
103 * <li>If there are no parameters, no formatter is used.
104 * <li>Otherwise, if the string contains "{0" then
105 * java.text.MessageFormat is used to format the string.
106 * <li>Otherwise no formatting is performed.
107 * </ul>
108 * <p>
109 *
110 * @param record the log record containing the raw message
111 * @return a localized and formatted message
112 */
113 public synchronized String formatMessage(LogRecord record) {
114 String format = record.getMessage();
115 java.util.ResourceBundle catalog = record.getResourceBundle();
116 if (catalog != null) {
117 try {
118 format = catalog.getString(record.getMessage());
119 } catch (java.util.MissingResourceException ex) {
120 // Drop through. Use record message as format
121 format = record.getMessage();
122 }
123 }
124 // Do the formatting.
125 try {
126 Object parameters[] = record.getParameters();
127 if (parameters == null || parameters.length == 0) {
128 // No parameters. Just return format string.
129 return format;
130 }
131 // Is it a java.text style format?
132 // Ideally we could match with
133 // Pattern.compile("\\{\\d").matcher(format).find())
134 // However the cost is 14% higher, so we cheaply check for
135 // 1 of the first 4 parameters
136 if (format.indexOf("{0") >= 0 || format.indexOf("{1") >=0 ||
137 format.indexOf("{2") >=0|| format.indexOf("{3") >=0) {
138 return java.text.MessageFormat.format(format, parameters);
139 }
140 return format;
141
142 } catch (Exception ex) {
143 // Formatting failed: use localized format string.
144 return format;
145 }
146 }
147 }
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