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Posted to commits@logging.apache.org by ma...@apache.org on 2018/12/27 16:23:36 UTC
svn commit: r1038174 [17/17] - in
/websites/production/logging/content/log4j: ./ log4j-kotlin-1.0.0/
log4j-kotlin-1.0.0/css/ log4j-kotlin-1.0.0/images/ log4j-kotlin-1.0.0/img/
log4j-kotlin-1.0.0/js/ log4j-kotlin-1.0.0/log4j-api-kotlin-sample/
log4j-kot...
Added: websites/production/logging/content/log4j/log4j-kotlin-1.0.0/usage.html
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--- websites/production/logging/content/log4j/log4j-kotlin-1.0.0/usage.html (added)
+++ websites/production/logging/content/log4j/log4j-kotlin-1.0.0/usage.html Thu Dec 27 16:23:34 2018
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+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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+
+ http://www.apache.org/licenses/LICENSE-2.0
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+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+ <title>Log4j_Kotlin – - Apache Log4j Kotlin API Parent</title>
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+<a href="http://www.apache.org/events/current-event.html">
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+<a href="https://logging.apache.org/">
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+ <a class="brand" href="https://logging.apache.org/log4j/kotlin/">Apache Log4j Kotlin API Parent ™</a>
+ <ul class="nav">
+ <li>
+
+
+ <a href="https://cwiki.apache.org/confluence/display/LOGGING/Home" class="external" target="_blank" title="Logging Wiki">Logging Wiki</a>
+ </li>
+ <li>
+
+
+ <a href="https://www.apache.org/" class="external" target="_blank" title="Apache">Apache</a>
+ </li>
+ <li>
+ <a href="../../" title="Logging Services">Logging Services</a>
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+ <a href="https://github.com/apache/logging-log4j-kotlin" class="external" target="_blank" title="GitHub">GitHub</a>
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+ <table class="layout-table">
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+ <td class="sidebar">
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+ <li class="nav-header"><i class="icon-home"></i>Apache Log4j Kotlin</li>
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+ <a href="index.html" title="About">About</a>
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+ <a href="download.html" title="Download">Download</a>
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+ <a href="usage.html" title="Usage">Usage</a>
+ </li>
+ </ul>
+ <ul class="nav nav-list">
+ <li class="nav-header"><i class="icon-pencil"></i>For Contributors</li>
+ <li class="none">
+ <a href="build.html" title="Building Log4j Kotlin from Source">Building Log4j Kotlin from Source</a>
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+ </ul>
+ <ul class="nav nav-list">
+ <li class="nav-header"><i class="icon-cog"></i>Component Reports</li>
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+ <a href="log4j-api-kotlin/index.html" title="Log4j Kotlin API">Log4j Kotlin API</a>
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+ <a href="log4j-api-kotlin-sample/index.html" title="Log4j Kotlin Samples">Log4j Kotlin Samples</a>
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+ </td>
+ <td class="content">
+ <div class="sect1">
+<h2 id="usage">Usage</h2>
+<div class="sectionbody">
+<div class="paragraph">
+<p>Using the Kotlin API is as simple as mixing in the <a href="https://github.com/apache/logging-log4j-kotlin/blob/master/log4j-api-kotlin/src/main/kotlin/org/apache/logging/log4j/kotlin/Logging.kt"><code>Logging</code></a> interface to your class. Example:</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">import org.apache.logging.log4j.kotlin.Logging
+
+class MyClass: BaseClass, Logging {
+ fun doStuff() {
+ logger.info("Doing stuff")
+ }
+ fun doStuffWithUser(user: User) {
+ logger.info { "Doing stuff with ${user.name}." }
+ }
+}</code></pre>
+</div>
+</div>
+<div class="paragraph">
+<p>The <code>Logging</code> interface can also be mixed into <code>object</code> declarations, including companions. This is generally preferable over the previous approach as there is a single logger created for every instance of the class.</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">import org.apache.logging.log4j.kotlin.Logging
+
+class MyClass: BaseClass {
+ companion object : Logging
+
+ ...
+}</code></pre>
+</div>
+</div>
+<div class="paragraph">
+<p>Alternatively, a more traditional style can be used to instantiate a logger instance:</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">import org.apache.logging.log4j.kotlin
+
+class MyClass: BaseClass {
+ val logger = logger()
+
+ ...
+}</code></pre>
+</div>
+</div>
+<div class="paragraph">
+<p>The function <code>logger()</code> is an extension function on the <code>Any</code> type (or more specifically, any type <code>T</code> that extends <code>Any</code>).</p>
+</div>
+<div class="sect2">
+<h3 id="api_documentation">API Documentation</h3>
+<div class="paragraph">
+<p>See <a href="https://logging.apache.org/TODO">KDocs</a>.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="configuration">Configuration</h3>
+<div class="paragraph">
+<p>Log4j Kotlin API uses <a href="https://logging.apache.org/log4j/2.x/manual/configuration.html">Log4j configuration</a> by default.</p>
+</div>
+<div class="paragraph">
+<p>This supports XML, properties files, and Java-based builders, as well as JSON and YAML with additional dependencies.</p>
+</div>
+</div>
+<div class="sect2">
+<h3 id="substituting_parameters">Substituting Parameters</h3>
+<div class="paragraph">
+<p>Unlike Java, Kotlin provides native functionality for <a href="https://kotlinlang.org/docs/reference/basic-syntax.html#using-string-templates">string templates</a>.</p>
+</div>
+<div class="paragraph">
+<p>However, using a string template still incurs the message construction cost if the logger level is not enabled. To avoid this, prefer passing a lambda which won’t be evaluated until necessary.</p>
+</div>
+<div class="paragraph">
+<p>For example:</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">logger.debug { "Logging in user ${user.name} with birthday ${user.calcBirthday()}" }</code></pre>
+</div>
+</div>
+</div>
+<div class="sect2">
+<h3 id="logger_names">Logger Names</h3>
+<div class="paragraph">
+<p>Most logging implementations use a hierarchical scheme for matching logger names with logging configuration.</p>
+</div>
+<div class="paragraph">
+<p>In this scheme the logger name hierarchy is represented by '.' characters in the logger name, in a fashion very similar to the hierarchy used for Java/Kotlin package names.</p>
+</div>
+<div class="paragraph">
+<p>The <code>Logger</code> property added by the <code>Logging</code> interface follows this convention: the interface ensures the <code>Logger</code> is automatically named according to the class it is being used in.</p>
+</div>
+<div class="paragraph">
+<p>The value returned when calling the <code>logger()</code> extension method depends on the receiver of the extension. When called within an Object as shown above, the receiver is <code>this</code> and therefore the logger will again be named according to the class it is being used in. However, a logger named via another class can be obtained as well:</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">import org.apache.logging.log4j.kotlin
+
+class MyClass: BaseClass {
+ val logger = SomeOtherClass.logger()
+
+ ...
+}</code></pre>
+</div>
+</div>
+<div class="sect3">
+<h4 id="explicitly_named_loggers">Explicitly Named Loggers</h4>
+<div class="paragraph">
+<p>An explicitly-named logger may be obtained via the <code>logger</code> function that takes a <code>name</code> parameter:</p>
+</div>
+<div class="listingblock">
+<div class="content">
+<pre class="highlight"><code class="language-kotlin" data-lang="kotlin">import org.apache.logging.log4j.kotlin
+
+class MyClass: BaseClass {
+ val logger = logger("MyCustomLoggerName")
+
+ ...
+}</code></pre>
+</div>
+</div>
+<div class="paragraph">
+<p>This is also needed in scopes that do not have a <code>this</code> Object, such as top-level functions.</p>
+</div>
+</div>
+</div>
+</div>
+</div>
+ </td>
+ </tr>
+ </table>
+</div>
+
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