-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.log4j;
-
-import org.apache.log4j.spi.LoggingEvent;
-import org.apache.log4j.helpers.PatternParser;
-import org.apache.log4j.helpers.PatternConverter;
-
-
-// Contributors: Nelson Minar <nelson@monkey.org>
-// Anders Kristensen <akristensen@dynamicsoft.com>
-
-/**
-
- A flexible layout configurable with pattern string.
-
- This code is known to have synchronization and other issues
- which are not present in org.apache.log4j.EnhancedPatternLayout.
- EnhancedPatternLayout should be used in preference to PatternLayout.
- EnhancedPatternLayout is distributed in the log4j extras companion.
-
- <p>The goal of this class is to {@link #format format} a {@link
- LoggingEvent} and return the results as a String. The results
- depend on the <em>conversion pattern</em>.
-
- <p>The conversion pattern is closely related to the conversion
- pattern of the printf function in C. A conversion pattern is
- composed of literal text and format control expressions called
- <em>conversion specifiers</em>.
-
- <p><i>You are free to insert any literal text within the conversion
- pattern.</i>
-
- <p>Each conversion specifier starts with a percent sign (%) and is
- followed by optional <em>format modifiers</em> and a <em>conversion
- character</em>. The conversion character specifies the type of
- data, e.g. category, priority, date, thread name. The format
- modifiers control such things as field width, padding, left and
- right justification. The following is a simple example.
-
- <p>Let the conversion pattern be <b>"%-5p [%t]: %m%n"</b> and assume
- that the log4j environment was set to use a PatternLayout. Then the
- statements
- <pre>
- Category root = Category.getRoot();
- root.debug("Message 1");
- root.warn("Message 2");
- </pre>
- would yield the output
- <pre>
- DEBUG [main]: Message 1
- WARN [main]: Message 2
- </pre>
-
- <p>Note that there is no explicit separator between text and
- conversion specifiers. The pattern parser knows when it has reached
- the end of a conversion specifier when it reads a conversion
- character. In the example above the conversion specifier
- <b>%-5p</b> means the priority of the logging event should be left
- justified to a width of five characters.
-
- The recognized conversion characters are
-
- <p>
- <table border="1" CELLPADDING="8">
- <th>Conversion Character</th>
- <th>Effect</th>
-
- <tr>
- <td align=center><b>c</b></td>
-
- <td>Used to output the category of the logging event. The
- category conversion specifier can be optionally followed by
- <em>precision specifier</em>, that is a decimal constant in
- brackets.
-
- <p>If a precision specifier is given, then only the corresponding
- number of right most components of the category name will be
- printed. By default the category name is printed in full.
-
- <p>For example, for the category name "a.b.c" the pattern
- <b>%c{2}</b> will output "b.c".
-
- </td>
- </tr>
-
- <tr>
- <td align=center><b>C</b></td>
-
- <td>Used to output the fully qualified class name of the caller
- issuing the logging request. This conversion specifier
- can be optionally followed by <em>precision specifier</em>, that
- is a decimal constant in brackets.
-
- <p>If a precision specifier is given, then only the corresponding
- number of right most components of the class name will be
- printed. By default the class name is output in fully qualified form.
-
- <p>For example, for the class name "org.apache.xyz.SomeClass", the
- pattern <b>%C{1}</b> will output "SomeClass".
-
- <p><b>WARNING</b> Generating the caller class information is
- slow. Thus, use should be avoided unless execution speed is
- not an issue.
-
- </td>
- </tr>
-
- <tr> <td align=center><b>d</b></td> <td>Used to output the date of
- the logging event. The date conversion specifier may be
- followed by a <em>date format specifier</em> enclosed between
- braces. For example, <b>%d{HH:mm:ss,SSS}</b> or
- <b>%d{dd MMM yyyy HH:mm:ss,SSS}</b>. If no
- date format specifier is given then ISO8601 format is
- assumed.
-
- <p>The date format specifier admits the same syntax as the
- time pattern string of the {@link
- java.text.SimpleDateFormat}. Although part of the standard
- JDK, the performance of <code>SimpleDateFormat</code> is
- quite poor.
-
- <p>For better results it is recommended to use the log4j date
- formatters. These can be specified using one of the strings
- "ABSOLUTE", "DATE" and "ISO8601" for specifying {@link
- org.apache.log4j.helpers.AbsoluteTimeDateFormat
- AbsoluteTimeDateFormat}, {@link
- org.apache.log4j.helpers.DateTimeDateFormat DateTimeDateFormat}
- and respectively {@link
- org.apache.log4j.helpers.ISO8601DateFormat
- ISO8601DateFormat}. For example, <b>%d{ISO8601}</b> or
- <b>%d{ABSOLUTE}</b>.
-
- <p>These dedicated date formatters perform significantly
- better than {@link java.text.SimpleDateFormat}.
- </td>
- </tr>
-
- <tr>
- <td align=center><b>F</b></td>
-
- <td>Used to output the file name where the logging request was
- issued.
-
- <p><b>WARNING</b> Generating caller location information is
- extremely slow and should be avoided unless execution speed
- is not an issue.
-
- </tr>
-
- <tr>
- <td align=center><b>l</b></td>
-
- <td>Used to output location information of the caller which generated
- the logging event.
-
- <p>The location information depends on the JVM implementation but
- usually consists of the fully qualified name of the calling
- method followed by the callers source the file name and line
- number between parentheses.
-
- <p>The location information can be very useful. However, its
- generation is <em>extremely</em> slow and should be avoided
- unless execution speed is not an issue.
-
- </td>
- </tr>
-
- <tr>
- <td align=center><b>L</b></td>
-
- <td>Used to output the line number from where the logging request
- was issued.
-
- <p><b>WARNING</b> Generating caller location information is
- extremely slow and should be avoided unless execution speed
- is not an issue.
-
- </tr>
-
-
- <tr>
- <td align=center><b>m</b></td>
- <td>Used to output the application supplied message associated with
- the logging event.</td>
- </tr>
-
- <tr>
- <td align=center><b>M</b></td>
-
- <td>Used to output the method name where the logging request was
- issued.
-
- <p><b>WARNING</b> Generating caller location information is
- extremely slow and should be avoided unless execution speed
- is not an issue.
-
- </tr>
-
- <tr>
- <td align=center><b>n</b></td>
-
- <td>Outputs the platform dependent line separator character or
- characters.
-
- <p>This conversion character offers practically the same
- performance as using non-portable line separator strings such as
- "\n", or "\r\n". Thus, it is the preferred way of specifying a
- line separator.
-
-
- </tr>
-
- <tr>
- <td align=center><b>p</b></td>
- <td>Used to output the priority of the logging event.</td>
- </tr>
-
- <tr>
-
- <td align=center><b>r</b></td>
-
- <td>Used to output the number of milliseconds elapsed from the construction
- of the layout until the creation of the logging event.</td>
- </tr>
-
-
- <tr>
- <td align=center><b>t</b></td>
-
- <td>Used to output the name of the thread that generated the
- logging event.</td>
-
- </tr>
-
- <tr>
-
- <td align=center><b>x</b></td>
-
- <td>Used to output the NDC (nested diagnostic context) associated
- with the thread that generated the logging event.
- </td>
- </tr>
-
-
- <tr>
- <td align=center><b>X</b></td>
-
- <td>
-
- <p>Used to output the MDC (mapped diagnostic context) associated
- with the thread that generated the logging event. The <b>X</b>
- conversion character <em>must</em> be followed by the key for the
- map placed between braces, as in <b>%X{clientNumber}</b> where
- <code>clientNumber</code> is the key. The value in the MDC
- corresponding to the key will be output.</p>
-
- <p>See {@link MDC} class for more details.
- </p>
-
- </td>
- </tr>
-
- <tr>
-
- <td align=center><b>%</b></td>
-
- <td>The sequence %% outputs a single percent sign.
- </td>
- </tr>
-
- </table>
-
- <p>By default the relevant information is output as is. However,
- with the aid of format modifiers it is possible to change the
- minimum field width, the maximum field width and justification.
-
- <p>The optional format modifier is placed between the percent sign
- and the conversion character.
-
- <p>The first optional format modifier is the <em>left justification
- flag</em> which is just the minus (-) character. Then comes the
- optional <em>minimum field width</em> modifier. This is a decimal
- constant that represents the minimum number of characters to
- output. If the data item requires fewer characters, it is padded on
- either the left or the right until the minimum width is
- reached. The default is to pad on the left (right justify) but you
- can specify right padding with the left justification flag. The
- padding character is space. If the data item is larger than the
- minimum field width, the field is expanded to accommodate the
- data. The value is never truncated.
-
- <p>This behavior can be changed using the <em>maximum field
- width</em> modifier which is designated by a period followed by a
- decimal constant. If the data item is longer than the maximum
- field, then the extra characters are removed from the
- <em>beginning</em> of the data item and not from the end. For
- example, it the maximum field width is eight and the data item is
- ten characters long, then the first two characters of the data item
- are dropped. This behavior deviates from the printf function in C
- where truncation is done from the end.
-
- <p>Below are various format modifier examples for the category
- conversion specifier.
-
- <p>
- <TABLE BORDER=1 CELLPADDING=8>
- <th>Format modifier
- <th>left justify
- <th>minimum width
- <th>maximum width
- <th>comment
-
- <tr>
- <td align=center>%20c</td>
- <td align=center>false</td>
- <td align=center>20</td>
- <td align=center>none</td>
-
- <td>Left pad with spaces if the category name is less than 20
- characters long.
-
- <tr> <td align=center>%-20c</td> <td align=center>true</td> <td
- align=center>20</td> <td align=center>none</td> <td>Right pad with
- spaces if the category name is less than 20 characters long.
-
- <tr>
- <td align=center>%.30c</td>
- <td align=center>NA</td>
- <td align=center>none</td>
- <td align=center>30</td>
-
- <td>Truncate from the beginning if the category name is longer than 30
- characters.
-
- <tr>
- <td align=center>%20.30c</td>
- <td align=center>false</td>
- <td align=center>20</td>
- <td align=center>30</td>
-
- <td>Left pad with spaces if the category name is shorter than 20
- characters. However, if category name is longer than 30 characters,
- then truncate from the beginning.
-
- <tr>
- <td align=center>%-20.30c</td>
- <td align=center>true</td>
- <td align=center>20</td>
- <td align=center>30</td>
-
- <td>Right pad with spaces if the category name is shorter than 20
- characters. However, if category name is longer than 30 characters,
- then truncate from the beginning.
-
- </table>
-
- <p>Below are some examples of conversion patterns.
-
- <dl>
-
- <p><dt><b>%r [%t] %-5p %c %x - %m%n</b>
- <p><dd>This is essentially the TTCC layout.
-
- <p><dt><b>%-6r [%15.15t] %-5p %30.30c %x - %m%n</b>
-
- <p><dd>Similar to the TTCC layout except that the relative time is
- right padded if less than 6 digits, thread name is right padded if
- less than 15 characters and truncated if longer and the category
- name is left padded if shorter than 30 characters and truncated if
- longer.
-
- </dl>
-
- <p>The above text is largely inspired from Peter A. Darnell and
- Philip E. Margolis' highly recommended book "C -- a Software
- Engineering Approach", ISBN 0-387-97389-3.
-
- @author <a href="mailto:cakalijp@Maritz.com">James P. Cakalic</a>
- @author Ceki Gülcü
-
-
- @since 0.8.2 */
-public class PatternLayout extends Layout {
-
-
- /** Default pattern string for log output. Currently set to the
- string <b>"%m%n"</b> which just prints the application supplied
- message. */
- public final static String DEFAULT_CONVERSION_PATTERN ="%m%n";
-
- /** A conversion pattern equivalent to the TTCCCLayout.
- Current value is <b>%r [%t] %p %c %x - %m%n</b>. */
- public final static String TTCC_CONVERSION_PATTERN
- = "%r [%t] %p %c %x - %m%n";
-
-
- protected final int BUF_SIZE = 256;
- protected final int MAX_CAPACITY = 1024;
-
-
- // output buffer appended to when format() is invoked
- private StringBuffer sbuf = new StringBuffer(BUF_SIZE);
-
- private String pattern;
-
- private PatternConverter head;
-
- /**
- Constructs a PatternLayout using the DEFAULT_LAYOUT_PATTERN.
-
- The default pattern just produces the application supplied message.
- */
- public PatternLayout() {
- this(DEFAULT_CONVERSION_PATTERN);
- }
-
- /**
- Constructs a PatternLayout using the supplied conversion pattern.
- */
- public PatternLayout(String pattern) {
- this.pattern = pattern;
- head = createPatternParser((pattern == null) ? DEFAULT_CONVERSION_PATTERN :
- pattern).parse();
- }
-
- /**
- Set the <b>ConversionPattern</b> option. This is the string which
- controls formatting and consists of a mix of literal content and
- conversion specifiers.
- */
- public
- void setConversionPattern(String conversionPattern) {
- pattern = conversionPattern;
- head = createPatternParser(conversionPattern).parse();
- }
-
- /**
- Returns the value of the <b>ConversionPattern</b> option.
- */
- public
- String getConversionPattern() {
- return pattern;
- }
-
- /**
- Does not do anything as options become effective
- */
- public
- void activateOptions() {
- // nothing to do.
- }
-
- /**
- The PatternLayout does not handle the throwable contained within
- {@link LoggingEvent LoggingEvents}. Thus, it returns
- <code>true</code>.
-
- @since 0.8.4 */
- public
- boolean ignoresThrowable() {
- return true;
- }
-
- /**
- Returns PatternParser used to parse the conversion string. Subclasses
- may override this to return a subclass of PatternParser which recognize
- custom conversion characters.
-
- @since 0.9.0
- */
- protected PatternParser createPatternParser(String pattern) {
- return new PatternParser(pattern);
- }
-
-
- /**
- Produces a formatted string as specified by the conversion pattern.
- */
- public String format(LoggingEvent event) {
- // Reset working stringbuffer
- if(sbuf.capacity() > MAX_CAPACITY) {
- sbuf = new StringBuffer(BUF_SIZE);
- } else {
- sbuf.setLength(0);
- }
-
- PatternConverter c = head;
-
- while(c != null) {
- c.format(sbuf, event);
- c = c.next;
- }
- return sbuf.toString();
- }
-}