Data Mapper Pattern: Complexe query from Service Layer

Question

I\'m sing the Data Mapper Pattern in Zend Framework. This works well so far, but now I got to a point where I need your help/opinion. So let\'s start with the Code:

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Answer 1

In my limited experience with data mappers I have found the following approach to work quite well for the scenarios I have encountered so far:

public function getPeopleByHaircolorAndAge($haircolor, $age, $limit=null, $offset=null)
{
    $people = new PersonCollection;
    $people->filterByHaircolor($haircolor);
    $people->filterByAge($age);
    $people->setLimit($limit);
    $people->setOffset($offset);

    $personCollectionMapper = new PersonCollectionMapper;
    $personCollectionMapper->fetch($people);

    return $people;
}

By instantiating the domain object first I have the option to set filters and other variables that the data mapper can read from the object when it is injected into the mapper.

To me this has been the superior approach so far compared to having multiple mapper methods that returns a domain object.