Restore

For completion, let's talk about restoring a deleted fact. You do this by defining yet another successor.

[FactType("Construction.Project.Restored")]
public record ProjectRestored(ProjectDeleted deleted);

await j.Fact(new ProjectRestored(projectADeleted));

Again, you need to add this fact to the specification for it to have an effect.

var projectsCreatedByUser = Given<User>.Match(u =>
    u.Successors().OfType<Project>(p => p.creator)
        .Where(p => !p.Successors().OfType<ProjectDeleted>(d => d.project).Any(
            d => !d.Successors().OfType<ProjectRestored>(r => r.deleted).Any()))
);

ImmutableList<Project> projects = await j.Query(projectsCreatedByUser, user);

And it's back!

Pattern Extensions

Because these are such common patterns, Jinaga provides some shorthand extensions to make them easier to write. You can find these in the Jinaga.Patterns namespace.

using Jinaga.Patterns;

var projectsCreatedByUserWithoutRestore = Given<User>.Match(u =>
    u.Successors().OfType<Project>(p => p.creator)
        .WhereNotDeleted((ProjectDeleted d) => d.project)
);

var projectsCreatedByUserWithRestore = Given<User>.Match(u =>
    u.Successors().OfType<Project>(p => p.creator)
        .WhereNotDeletedOrRestored((ProjectDeleted d) => d.project,
            (ProjectRestored r) => r.deleted)
);

Continue With

Mutable Properties