<?php
namespace Wikibase\Content;
use RuntimeException;
use Wikibase\DataModel\Entity\EntityDocument;
use Wikibase\DataModel\Entity\EntityId;
/**
* EntityHolder implementing deferred copying.
*
* @license GPL-2.0+
* @author Daniel Kinzler
*/
class DeferredCopyEntityHolder implements EntityHolder {
/**
* @var EntityHolder
*/
private $entityHolder;
/**
* @var EntityDocument|null
*/
private $entity = null;
/**
* @param EntityHolder $entityHolder
*/
public function __construct( EntityHolder $entityHolder ) {
$this->entityHolder = $entityHolder;
}
/**
* @see EntityHolder::getEntityId
*
* This implements lazy initialization of the entity: when called for the first time,
* this method will call getEntity() on the EntityHolder passed to the constructor,
* and then deep clone the entity returned. The resulting copy is returned.
* Subsequent calls will return the same entity.
*
* @param string $expectedClass The class with which the result is expected to be compatible.
* Defaults to EntityDocument.
*
* @throws RuntimeException If the entity held by this EntityHolder is not compatible with $expectedClass.
* @return EntityDocument
*/
public function getEntity( $expectedClass = EntityDocument::class ) {
if ( !$this->entity ) {
$entity = $this->entityHolder->getEntity( $expectedClass );
$this->entity = $entity->copy();
}
return $this->entity;
}
/**
* @see EntityHolder::getEntityId
*
* @return EntityId|null
*/
public function getEntityId() {
return $this->entityHolder->getEntityId();
}
/**
* @see EntityHolder::getEntityType
*
* @return string
*/
public function getEntityType() {
return $this->entityHolder->getEntityType();
}
}