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<?xml version="1.0" encoding="utf-8"?>
<!-- Reviewed: no -->
<sect1 id="zend.loader.spl-autoloader">
<title>The SplAutoloader Interface</title>
<sect2 id="zend.loader.spl-autoloader.intro">
<title>Overview</title>
<para>
While any valid PHP callback may be registered with
<function>spl_autoload_register()</function>, Zend Framework autoloaders often provide
more flexibility by being stateful and allowing configuration. To provide a common
interface, Zend Framework provides the <interfacename>SplAutoloader</interfacename>
interface.
</para>
<para>
Objects implementing this interface provide a standard mechanism for configuration, a
method that may be invoked to attempt to load a class, and a method for registering with
the SPL autoloading mechanism.
</para>
</sect2>
<sect2 id="zend.loader.spl-autoloader.quick-start">
<title>Quick Start</title>
<para>
To create your own autoloading mechanism, simply create a class implementing the
<interfacename>SplAutoloader</interfacename> interface (you may review the methods
defined in the <link linkend="zend.loader.spl-autoloader.methods">Methods
section</link>). As a simple example, consider the following autoloader, which will look
for a class file named after the class within a list of registered directories.
</para>
<programlisting language="php"><![CDATA[
require_once 'Zend/Loader/SplAutoloader.php';
class Custom_ModifiedIncludePathAutoloader implements Zend_Loader_SplAutoloader
{
protected $paths = array();
public function __construct($options = null)
{
if (null !== $options) {
$this->setOptions($options);
}
}
public function setOptions($options)
{
if (!is_array($options) && !($options instanceof Traversable)) {
throw new InvalidArgumentException();
}
foreach ($options as $path) {
if (!in_array($path, $this->paths)) {
$this->paths[] = $path;
}
}
return $this;
}
public function autoload($classname)
{
$filename = $classname . '.php';
foreach ($this->paths as $path) {
$test = $path . DIRECTORY_SEPARATOR . $filename;
if (file_exists($test)) {
return include($test);
}
}
return false;
}
public function register()
{
spl_autoload_register(array($this, 'autoload'));
}
}
]]></programlisting>
</sect2>
<sect2 id="zend.loader.spl-autoloader.options">
<title>Configuration Options</title>
<para>
This component defines no configuration options, as it is an interface.
</para>
</sect2>
<sect2 id="zend.loader.spl-autoloader.methods">
<title>Available Methods</title>
<variablelist>
<varlistentry id="zend.loader.spl-autoloader.methods.constructor">
<term>
<methodsynopsis>
<methodname>__construct</methodname>
<methodparam>
<funcparams>$options = null</funcparams>
</methodparam>
</methodsynopsis>
</term>
<listitem>
<para>
Initialize and configure an autoloader
</para>
<para>
Autoloader constructors should optionally receive configuration options.
Typically, if received, these will be passed to the
<methodname>setOptions()</methodname> method to process.
</para>
</listitem>
</varlistentry>
<varlistentry id="zend.loader.spl-autoloader.methods.set-options">
<term>
<methodsynopsis>
<methodname>setOptions</methodname>
<methodparam>
<funcparams>$options</funcparams>
</methodparam>
</methodsynopsis>
</term>
<listitem>
<para>
Configure the autoloader state
</para>
<para>
Used to configure the autoloader. Typically, it should expect either an array or
a <interfacename>Traversable</interfacename> object, though validation of the
options is left to implementation. Additionally, it is recommended that the
method return the autoloader instance in order to implement a fluent interface.
</para>
</listitem>
</varlistentry>
<varlistentry id="zend.loader.spl-autoloader.methods.autoload">
<term>
<methodsynopsis>
<methodname>autoload</methodname>
<methodparam>
<funcparams>$classname</funcparams>
</methodparam>
</methodsynopsis>
</term>
<listitem>
<para>
Attempt to resolve a class name to the file defining it
</para>
<para>
This method should be used to resolve a class name to the file defining it. When
a positive match is found, return the class name; otherwise, return a boolean
false.
</para>
</listitem>
</varlistentry>
<varlistentry id="zend.loader.spl-autoloader.methods.register">
<term>
<methodsynopsis>
<methodname>register</methodname>
</methodsynopsis>
</term>
<listitem>
<para>
Register the autoloader with the SPL autoloader
</para>
<para>
Should be used to register the autoloader instance with
<function>spl_autoload_register()</function>. Invariably, the method
should look like the following:
</para>
<programlisting language="php"><![CDATA[
public function register()
{
spl_autoload_register(array($this, 'autoload'));
}
]]></programlisting>
</listitem>
</varlistentry>
</variablelist>
</sect2>
<sect2 id="zend.loader.spl-autoloader.examples">
<title>Examples</title>
<para>
Please see the <link linkend="zend.loader.spl-autoloader.quick-start">Quick Start</link>
for a complete example.
</para>
</sect2>
</sect1>
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