spec.php

<?php

interface JobInterface
{
    /**
     * Czy wartość spełnia kryteria?
     * 
     * @param mixed $value
     * @return bool
     */
    public function isSatisified($value);
    
    /**
     * @return mixed
     */
    public function doJob();
}

class Job1 implements JobInterface
{
    public function isSatisified($value)
    {
        return $value === 0;
    }
    
    public function doJob()
    {
        printf("%s doing the job<br>", __METHOD__);
    }
}

class Job2 implements JobInterface
{
    public function isSatisified($value)
    {
        return $value === 1;
    }
    
    public function doJob()
    {
        printf("%s doing the job<br>", __METHOD__);
    }
}

class JobExecuter
{
    private $jobs = [];
    
    /**
     * iniekcja przez konstruktor
     * @param JobInterface[] $jobs
     */
    public function __construct(array $jobs)
    {
        $this->jobs = $jobs;
    }
    
    /**
     * lub jak kto woli przez metodę
     * @param JobInterface $job
     */
    public function addJob(JobInterface $job)
    {
        $this->jobs[] = $job;
    }
    
    public function execute($value)
    {
        foreach ($this->jobs as $job) {
            if ($job->isSatisfied($value)) {
                return $job->doJob($value);
            }
        }
        
        throw new \RuntimeException(sprintf('No job executed for %d', $value));
    }
}

$runner = new JobExecuter();
$runner->addJob(new Job1());
$runner->addJob(new Job2());

// lub
$runner = new JobExecuter([new Job1(), new Job2()])

$runner->execute(mt_rand(0,1));