Specifications

ISpecification.cs

public interface ISpecification<T>
{
    Expression<Func<T, bool>> IsSatisfied();
}

Repository.cs

public virtual IQueryable<T> Query(ISpecification<T> query)
{
    var specifications = _specificationPolicies
        .Where(p => p.Applies<T>())
        .Select(p => p.Build<T>())
        .ToList();
    specifications.Add(query);

    var specification = _specificationComposer.Compose(specifications);
    return Entities.Where(specification.IsSatisfied());
}