CerField.inc in Corresponding Entity References 7.3
Contains the base class for CER field plugins.
A field plugin tells CER how to interact with fields of a certain type. If a particular field type integrates with Entity API, its CER plugin can be as simple as extending CerField and implementing the getTargetType() method.
@todo More info about extending CerFieldHandler to further customize field plugins.
File
includes/CerField.incView source
<?php
/**
* @file
* Contains the base class for CER field plugins.
*
* A field plugin tells CER how to interact with fields of a certain type. If a particular
* field type integrates with Entity API, its CER plugin can be as simple as extending
* CerField and implementing the getTargetType() method.
*
* @todo
* More info about extending CerFieldHandler to further customize field plugins.
*/
/**
* @class
* Represents a single field instance.
*/
abstract class CerField extends FieldInstance {
/**
* @var array
* The plugin definition.
*/
protected $plugin;
/**
* @var array
*/
protected $settings = array();
/**
* @var string
*/
public $fieldTypeLabel;
/**
* Gets the type of entity that can be referenced by this field, e.g. 'node'.
*
* @return string
*/
public abstract function getTargetType();
/**
* Constructor. Pretty self-explanatory!
*/
public function __construct(array $plugin) {
// Store a copy of our plugin definition.
$this->plugin = $plugin;
list($entity_type, $bundle, $field_name) = explode(':', $plugin['identifier']);
parent::__construct($entity_type, $bundle, $field_name);
// Store a copy of the field settings for convenience. At the time of this
// writing, this is needed by the Entity Reference, Node Reference,
// and Term Reference plugins.
$info = field_info_field($this->name);
$this->settings = $info['settings'];
$type_info = field_info_field_types($info['type']);
$this->fieldTypeLabel = $type_info['label'];
}
/**
* Returns a CerFieldHandler subclass instance for the given entity.
*
* @param object $entity
* The entity to be wrapped by the handler.
*
* @return CerFieldHandler
*/
public function getHandler(EntityDrupalWrapper $entity) {
return new $this->plugin['handler']($this, $entity);
}
/**
* Returns the bundles that this field instance can reference.
*
* @return array
*/
public function getTargetBundles() {
$info = entity_get_info($this
->getTargetType());
return array_keys($info['bundles']);
}
/**
* Overridden.
*/
public function requireParent() {
return $this->plugin['require parent'];
}
/**
* Overridden.
*/
public function getParents() {
return array_map('CerField::getPlugin', $this->plugin['parents']);
}
/**
* Returns information about a particular field plugin by its identifier, or all
* available plugins (i.e., defined by hook_cer_fields()) if no identifier is given.
* The aggregated result of hook_cer_fields() is statically cached.
*/
public static function getPluginInfo($identifier = NULL) {
$info =& drupal_static(__METHOD__);
if (!isset($info)) {
$info = module_invoke_all('cer_fields');
foreach ($info as $key => &$field) {
$field += array(
'identifier' => $key,
'parents' => array(),
'require parent' => FALSE,
'handler' => 'CerFieldHandler',
);
}
drupal_alter('cer_fields', $info);
}
return $identifier ? isset($info[$identifier]) ? $info[$identifier] : NULL : $info;
}
/**
* Returns a single field plugin instance, by its identifier. All plugin instances
* are statically cached.
*
* @param string $identifier
* The plugin's identifier, in the format entity_type:bundle:field_name.
*
* @return CerField
*
* @throws Exception if there's no plugin for the given identifier. Why so harsh, you
* ask? Because CerFieldChain::unpack() utterly depends on being able to get plugin
* instances for every field in the chain, and if it can't, it could result in myriad
* weird and serious problems. Throwing an exception will head that off at the pass.
*/
public static function getPlugin($identifier) {
$instances =& drupal_static(__METHOD__);
if (!isset($instances[$identifier])) {
$info = self::getPluginInfo($identifier);
if ($info) {
$instances[$identifier] = new $info['class']($info);
}
else {
throw new Exception("Cannot get instance of invalid plugin {$identifier}.");
}
}
return $instances[$identifier];
}
}