PHP code example of rezozero / tree-walker

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

rezozero / tree-walker example snippets

use RZ\TreeWalker\WalkerInterface;
use RZ\TreeWalker\WalkerContextInterface;
use RZ\TreeWalker\AbstractWalker;
use RZ\TreeWalker\Definition\ContextualDefinitionTrait;

class Dummy
{
    // Current dummy identifier
    private $id;
    // Nested tree style current dummy parent identifier
    private $parentDummyId;

    public function hello(){
        return 'Hey Ho!';
    }

    public function getId(){
        return $this->id;
    }
}

class NotADummy
{
    // Nested tree style current dummy parent identifier
    private $parentDummyId;

    public function sayNothing(){
        return '…';
    }
}

class DummyWalkerContext implements WalkerContextInterface
{
    private $dummyRepository;
    private $notADummyRepository;

    public function __construct($dummyRepository, $notADummyRepository)
    {
        $this->dummyRepository = $dummyRepository;
        $this->notADummyRepository = $notADummyRepository;
    }

    public function getDummyRepository()
    {
        return $this->dummyRepository;
    }

    public function getNotADummyRepository()
    {
        return $this->notADummyRepository;
    }
}

final class DummyChildrenDefinition
{
    use ContextualDefinitionTrait;

    public function __invoke(Dummy $dummy, WalkerInterface $walker): array
    {
        if ($this->context instanceof DummyWalkerContext) {
            return array_merge(
                $this->context->getDummyRepository()->findByParentDummyId($dummy->getId()),
                $this->context->getNotADummyRepository()->findByParentDummyId($dummy->getId())
            );
        }
        throw new \InvalidArgumentException('Context should be instance of ' . DummyWalkerContext::class);
    }
}

final class DummyWalker extends AbstractWalker implements \IteratorAggregate
{
    protected function initializeDefinitions(): void
    {
        /*
         * All Tree-walker logic occurs here…
         * You are free to code any logic to fetch your item children, and
         * to alter it given your WalkerContextInterface such as security, request…
         */
        $this->addDefinition(Dummy::class, new DummyChildrenDefinition($this->getContext()));
    }
}

/*
 * Some stupid recursive function to 
 * walk entire entities tree graph
 */
function everyDummySayHello(WalkerInterface $walker) {
    if ($walker->getItem() instanceof Dummy) {
        echo $walker->getItem()->hello();
    }
    if ($walker->getItem() instanceof NotADummy) {
        echo $walker->getItem()->sayNothing();
    }
    if ($walker->count() > 0) {
        foreach ($walker as $childWalker) {
            // I love recursive functions…
            everyDummySayHello($childWalker);
        }
    }
}

// -------------------------------------------------------
// Just provide some $entityManager to fetch your entities 
// from a database, a file, or your fridge…
// -------------------------------------------------------
$dummyRepository = $entityManager->getRepository(Dummy::class);
$notADummyRepository = $entityManager->getRepository(NotADummy::class);
$firstItem = $dummyRepository->findOneById(1);

// Calling an AbstractWalker constructor is forbidden, always
// use static build method
$walker = DummyWalker::build(
    $firstItem,
    new DummyWalkerContext($dummyRepository, $notADummyRepository),
    3 // max level count
);

everyDummySayHello($walker);

final class DummyChildrenDefinition
{
    use ContextualDefinitionTrait;
    
    public function isStoppingCollectionOnceInvoked(): bool
    {
        return true;
    }

    public function __invoke(Dummy $dummy, WalkerInterface $walker): array
    {
        // ...
    }
}