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September 2007

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svn commit: r1584 - logback/trunk/logback-site/src/site/pages/manual
by noreply.ceki＠qos.ch 06 Sep '07

06 Sep '07

Author: ceki Date: Thu Sep 6 15:47:18 2007 New Revision: 1584 Modified: logback/trunk/logback-site/src/site/pages/manual/appenders.html Log: ongoing work on documentation Modified: logback/trunk/logback-site/src/site/pages/manual/appenders.html ============================================================================== --- logback/trunk/logback-site/src/site/pages/manual/appenders.html (original) +++ logback/trunk/logback-site/src/site/pages/manual/appenders.html Thu Sep 6 15:47:18 2007 @@ -43,11 +43,11 @@ <h2>What is an Appender?</h2> - <p> - Logback delegates the task of writing a logging event to appenders. - Appenders must implement the - <a href="../xref/ch/qos/logback/core/Appender.html"><code>ch.qos.logback.core.Appender</code></a> interface. - The salient methods of this interface are summarized below: + <p>Logback delegates the task of writing a logging event to + components called appenders. Appenders must implement the <a + href="../xref/ch/qos/logback/core/Appender.html"><code>ch.qos.logback.core.Appender</code></a> + interface. The salient methods of this interface are summarized + below: </p> <div class="source"><pre>package ch.qos.logback.core; @@ -67,28 +67,35 @@ }</pre></div> <p> - Most of the methods in the <code>Appender</code> interface are made of setter - and getter methods. A notable exception is the <code>doAppend()</code> - method taking an Object instance as its only parameter. - This method is perhaps the most important in the logback framework. - It is responsible for outputting the logging events in a suitable format - to the appropriate output device. Appenders are named entities. - This ensures that they can be referenced by name, a quality confirmed - to be especially significant in configuration scripts. - An appender can contain multiple filters, thus the <code>Appender</code> - interface extending the <code>FilterAttachable</code> interface. - Filters are discussed in detail in a subsequent chapter. + Most of the methods in the <code>Appender</code> interface are + made of setter and getter methods. A notable exception is the + <code>doAppend()</code> method taking an object instance of type + <em>E</em> as its only parameter. The actual type of <em>E</em> + would vary depending on the logback module. Within the + logback-classic module <em>E</em> would be of type <a + href="../apidocs/ch/qos/logback/classic/spi/LoggingEvent.html">LoggingEvent</a> + and within the logback-access module it would be of type <a + href="../apidocs/ch/qos/logback/access/spi/AccessEvent.html">AccessEvent</a>. + The <code>doAppend()</code> method is perhaps the most important + in the logback framework. It is responsible for outputting the + logging events in a suitable format to the appropriate output + device. Appenders are named entities. This ensures that they can + be referenced by name, a quality confirmed to be especially + significant in configuration scripts. An appender can contain + multiple filters, thus the <code>Appender</code> interface + extending the <code>FilterAttachable</code> interface. Filters + are discussed in detail in a subsequent chapter. </p> <p> - Appenders are ultimately responsible for outputting logging events. - However, they may delegate the actual formatting of the event to a - <code>Layout</code> object. - Each layout is associated with one and only one appender, referred to - as the containing appender. Some appenders have a built-in or fixed - event format, such that they do not require a layout. For example, the - <code>SocketAppender</code> simply serialize logging events before - transmitting them over the wire. + Appenders are ultimately responsible for outputting logging + events. However, they may delegate the actual formatting of the + event to a <code>Layout</code> object. Each layout is associated + with one and only one appender, referred to as the owning + appender. Some appenders have a built-in or fixed event format, + such that they do not require a layout. For example, the + <code>SocketAppender</code> simply serializes logging events + before transmitting them over the wire. </p> <a name="AppenderBase"></a> @@ -96,16 +103,17 @@ <p> The <a href="../xref/ch/qos/logback/core/AppenderBase.html"> - <code>ch.qos.logback.core.AppenderBase</code></a> class is an abstract - class implementing the <code>Appender</code> interface. - It provides basic functionality shared by all appenders, - such as methods for getting or setting their name, their started status, - their layout and their filters. - It is the super-class of all appenders shipped with logback. - Although an abstract class, <code>AppenderBase</code> actually implements the - <code>doAppend()</code> method in the <code>Append</code> interface. - Perhaps the clearest way to discuss <code>AppenderBase</code> class is by - presenting a bit of its actual source code. + <code>ch.qos.logback.core.AppenderBase</code></a> class is an + abstract class implementing the <code>Appender</code> interface. + It provides basic functionality shared by all appenders, such as + methods for getting or setting their name, their activation + status, their layout and their filters. It is the super-class of + all appenders shipped with logback. Although an abstract class, + <code>AppenderBase</code> actually implements the + <code>doAppend()</code> method in the <code>Append</code> + interface. Perhaps the clearest way to discuss + <code>AppenderBase</code> class is by presenting an excerpt of + actual source code. </p> <div class="source"><pre>public synchronized void doAppend(E eventObject) { @@ -157,21 +165,24 @@ </p> <p> - The first statement of the <code>doAppend()</code> method, once the <code>try</code> block - is reached, is to check whether the <code>started</code> field is true. - If it is not, <code>doAppend()</code> will send a warning message and return. - In other words, once stopped, it is impossible to write to a closed appender. - <code>Appender</code> objects implement the <code>LifeCycle</code> interface, - which implies that they implement <code>start()</code>, <code>stop()</code> - and <code>isStarted()</code> methods. After setting all the options of an appender, - Joran, logback's configuration framework, calls the <code>start()</code> - method to signal the appender to bind or activate its options. - Indeed, depending on the appender, certain options cannot be activated because - of interferences with other options, or appenders can even not start at all if - some options are missing. - For example, since file creation depends on truncation mode, - <code>FileAppender</code> cannot act on the value of its <code>File</code> option - until the value of the Append option is also known for certain. + The first statement of the <code>doAppend()</code> method, once + the <code>try</code> block is reached, is to check whether the + <code>started</code> field is true. If it is not, + <code>doAppend()</code> will send a warning message and return. + In other words, once stopped, it is impossible to write to a + closed appender. <code>Appender</code> objects implement the + <code>LifeCycle</code> interface, which implies that they + implement <code>start()</code>, <code>stop()</code> and + <code>isStarted()</code> methods. After setting all the options of + an appender, Joran, logback's configuration framework, calls the + <code>start()</code> method to signal the appender to bind or + activate its options. Indeed, depending on the appender, certain + options cannot be activated because of interferences with other + options, or appenders can even not start at all if some options + are missing. For example, since file creation depends on + truncation mode, <code>FileAppender</code> cannot act on the value + of its <code>File</code> option until the value of the Append + option is also known for certain. </p> <p>

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