Naskar.QueryOverSpec

A simple implementation of the Specification Pattern using NHibernate QueryOver. Create queries reusing simple predicates.

Refs

https://en.wikipedia.org/wiki/Specification_pattern

Nuget

https://www.nuget.org/packages/Naskar.QueryOverSpec

Examples:

[Test]
public void TestSpecification()
{
	// Arrange
	var course1 = new Course() { Name = "Java" };
	var course2 = new Course() { Name = "C#" };

	var vote1 = new Vote() { Course = course1, Mail = "test@naskar.com" };
	course1.Votes.Add(vote1);

	var courseByExample = _container.Resolve<IByExampleSpec<Course>>();
	var courseWithVotes = _container.Resolve<ICourseWithVotes>();

	var repository = _container.Resolve<IRepository>();
	repository.Add(course1);
	repository.Add(course2);

	// Act
	var list = repository.Find(
              courseWithVotes.By().
              And(courseByExample.By(new Course() { Name = "ava" })));

	// Assert
	list.Should().HaveCount(1);

	// Cleanup
	repository.RemoveAll<Course>();
}

Specification:

public class CourseWithVotes : ICourseWithVotes
{
	public ISpecification<Course> By()
	{
		Action<IQueryOver<Course, Course>> action = x => x.JoinQueryOver(y => y.Votes);
		return new QueryOverSpecification<Course>(action);
	}
}

Repository:

public IList<TEntity> Find<TEntity>(ISpecification<TEntity> spec) where TEntity : Entity
{
	var session = Factory.OpenSession();
	var query = session.QueryOver<TEntity>();

	var visitor = new QueryOverSpecificationVisitor<TEntity>(query);
	spec.Accept(visitor);

	var list = query.List();

	session.Close();
	return list;
}

More Examples