Jaxon

•    Version 4.x
•    Version 3.x
•    Version 2.x

Let's consider the following code, where 3 classes are registered with Jaxon.

$jaxon->register(Jaxon::CALLABLE_OBJECT, new JaxonClass1);
$jaxon->register(Jaxon::CALLABLE_OBJECT, new JaxonClass2);
$jaxon->register(Jaxon::CALLABLE_OBJECT, new JaxonClass3);
$jaxon->processRequest(); 

The 3 classes are instanciated each time a request is processed, even though only one will actually be used.

When classes are registered from a directory, autoloading allows when processing a request to instanciate only the class that was called.

$jaxon->addClassDir($dirA, $namespaceA);
$jaxon->addClassDir($dirB, $namespaceB);

if(!$jaxon->canProcessRequest())
{
    // When loading the page, all classes are loaded so the code can be generated.
    $jaxon->registerClasses();
}
else
{
    // When processing a request, the class that was called is autoloaded. 
    $jaxon->processRequest();
}

When the page loads, all Jaxon classes must be registered so the corresponding javascript code can be generated. But when processing a query, instanciating all classes is not necessary.
With autoloading, only the class requested by the query will be instanciated.

By default, Jaxon uses a simple implementation of the autoloading where class files are loaded with the require() PHP function. But it is also possible to make Jaxon use the Composer autoloader, or to use an autoloader from a third party.

Using Composer autoloader

A call to $jaxon->useComposerAutoloader() makes the Jaxon library use the Composer autoloader. From that moment, all the classes in a directory registered with a namespace will be loaded with the PSR-4 autoloader, while all classes in a directory registered without namespace will be loaded with the ClassMap autoloader.

// Use Composer autoloader
$jaxon->useComposerAutoloader();
$jaxon->addClassDir($dirA, $namespaceA);
$jaxon->addClassDir($dirB, $namespaceB);

Using a third party autoloader

To use an autoloader from a third-party, autoloading must be disabled in the Jaxon library, by calling $jaxon->disableAutoload(). From that moment, it is the responsibility of the developer to implement autoloading for the directories he registers.

The example below uses the autoloader from https://github.com/keradus/Psr4Autoloader.

// Register the namespaces with the autoloader
$loader = new Keradus\Psr4Autoloader;
$loader->register();
$loader->addNamespace($namespaceA, $dirA);
$loader->addNamespace($namespaceB, $dirB);

// The autoloader is disabled in Jaxon
$jaxon->disableAutoload();
$jaxon->addClassDir($dirA, $namespaceA);
$jaxon->addClassDir($dirB, $namespaceB);