Resolving ORM Query Hints 

The Query Hint Resolver service makes building configuration-based queries, like grids and API, easier and more flexible.

To map a hint to a custom tree walker, you can use DI container configuration, for example:

oro_security.query_hint.filter_by_current_user:
    public: false
    abstract: true
    tags:
        -
            name: oro_entity.query_hint
            hint: oro_security.filter_by_current_user
            alias: HINT_FILTER_BY_CURRENT_USER
            tree_walker: Oro\Bundle\SecurityBundle\ORM\Walker\CurrentUserWalker
            walker_hint_provider: oro_security.walker_hint_provider.current_user

The walker_hint_provider attribute is optional and can be used to provide a service to be used to set additional query hints required to work the walker specified in the attribute tree_walker. This service must implement QueryWalkerHintProviderInterface and must be registered in the DI container, for example:

oro_security.walker_hint_provider.current_user:
    public: false
    class: Oro\Bundle\SecurityBundle\ORM\Walker\CurrentUserWalkerHintProvider
    arguments:
         - '@security.token_storage'

To map a hint to a custom output walker, use the attribute output_walker instead of tree_walker in the DI container configuration, for example:

oro_translation.query_hint.translatable:
    public: false
    abstract: true
    tags:
        -
            name: oro_entity.query_hint
            hint: oro_translation.translatable
            alias: HINT_TRANSLATABLE
            output_walker: Oro\Component\DoctrineUtils\ORM\Walker\TranslatableSqlWalker

The following example shows how you can use hints in YAML configuration files:

datagrids:
    my-email-origins-grid:
        source:
            type: orm
            query:
                select:
                    - origin
                from:
                    - { table: Oro\Bundle\EmailBundle\Entity\EmailOrigin, alias: origin }
            hints:
                - HINT_FILTER_BY_CURRENT_USER