Implementing custom query logic

If we take a look at the implementation of the selectSObjectById base class method we have been using so far in this chapter, the buildQuerySObjectById method code shown as following, gives an indication of how we implement custom Selector methods; it also highlights the newQueryFactory base class method usage:

public List<SObject> selectSObjectsById(Set<Id>idSet) {
  return Database.query(buildQuerySObjectById());
}
private String buildQuerySObjectById() {
  return newQueryFactory().
           setCondition('id in :idSet').
           toSOQL();
}

The newQueryFactory method exposes an alternative object orientated way to express a SOQL query. It follows the fluent design model with its methods making the configuration less verbose. For more information on this approach see https://en.wikipedia.org/wiki/Fluent_interface.

The instance of fflib_QueryFactory returned by this method is preconfigured with the object, fields, order by and any field set...