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| <document xmlns="http://maven.apache.org/XDOC/2.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" | |
| xsi:schemaLocation="http://maven.apache.org/XDOC/2.0 http://maven.apache.org/xsd/xdoc-2.0.xsd"> | |
| <properties> | |
| <title>Introduction</title> | |
| </properties> | |
| <body> | |
| <section name="Introduction"> | |
| <p>There are three main concepts in Apache log4php: loggers, appenders and layouts. These three types of | |
| components work together to enable developers to log messages according to message type and level, and to | |
| control at runtime how these messages are formatted and where they are reported.</p> | |
| <subsection name="Loggers" id="Loggers"> | |
| <p>A logger is a component which will take your logging request and log it. Each class in a project | |
| can have an individual logger, or they can all use a common logger. Loggers are named entities; it is | |
| common to name them after the class which will use it for logging.</p> | |
| </subsection> | |
| <subsection name="Appenders" id="Appenders"> | |
| <p>Logging requests can be sent to multiple destinations and such destinations are called appenders. | |
| Appenders exist for console, files, syslog, database, sockets and other output destinations. One or | |
| more appenders can be attached to a logger. Each enabled logging request for a given logger will be | |
| forwarded to all the appenders in that logger.</p> | |
| </subsection> | |
| <subsection name="Layouts" id="Layouts"> | |
| <p>Layouts are components responsible for transforming a logging event into a string. Most appender | |
| classes require a layout class to convert the event to a string so that it can be logged.</p> | |
| </subsection> | |
| <subsection name="Levels" id ="Levels"> | |
| <p>A level describes the severity of a logging message. There are six levels, show here in descending order | |
| of severity.</p> | |
| <table> | |
| <thead> | |
| <tr> | |
| <th>Level</th> | |
| <th>Severity</th> | |
| <th>Description</th> | |
| </tr> | |
| </thead> | |
| <tbody> | |
| <tr> | |
| <td>FATAL</td> | |
| <td>Highest</td> | |
| <td>Very severe error events that will presumably lead the application to abort.</td> | |
| </tr> | |
| <tr> | |
| <td>ERROR</td> | |
| <td>...</td> | |
| <td>Error events that might still allow the application to continue running.</td> | |
| </tr> | |
| <tr> | |
| <td>WARN</td> | |
| <td>...</td> | |
| <td>Potentially harmful situations which still allow the application to continue running.</td> | |
| </tr> | |
| <tr> | |
| <td>INFO</td> | |
| <td>...</td> | |
| <td>Informational messages that highlight the progress of the application at coarse-grained level.</td> | |
| </tr> | |
| <tr> | |
| <td>DEBUG</td> | |
| <td>...</td> | |
| <td>Fine-grained informational events that are most useful to debug an application.</td> | |
| </tr> | |
| <tr> | |
| <td>TRACE</td> | |
| <td>Lowest</td> | |
| <td>Finest-grained informational events.</td> | |
| </tr> | |
| </tbody> | |
| </table> | |
| </subsection> | |
| </section> | |
| </body> | |
| </document> |