set multiple='false' in a form in a many to many relation symfony2

Question

I have a many-to-many relationship between two entities A and B.

So when adding a form, in order to add entityA to entityB, I am doing the

Answer 1

In EntityA, you have something like this, right?

public function setEntitiesB($data)
{
    $this->entitiesB = $data ;
}

Now because you can also receive single value instead of array of values, you need something like this:

public function setEntitiesB($data)
{
    if ( is_array($data) ) {
        $this->entitiesB = $data ;
    } else {
        $this->entitiesB->clear() ;
        $this->entitiesB->add($data) ;
    }
}