PetaPocoHierarchy Multi-Poco Mapping Helper

OrganizationParentRelator.cs

using PetaPocoHierarchy.Models;

namespace PetaPocoHierarchy.Services
{
    /// <summary>
    /// Set Organization Parent in the Organization Hierarchy
    /// </summary>
    /// <remarks>
    /// Based on logic for mapping demo: http://www.toptensoftware.com/Articles/115/PetaPoco-Mapping-One-to-Many-and-Many-to-One-Relationships
    /// </remarks>
    public class OrganizationParentRelator
    {
        private Organization _current;

        public Organization BuildHierarchy(Organization organization, Organization parent)
        {
            // Terminating call and prepare for PetaPoco callback with nulls
            if (organization == null)
                return _current;

            if (_current != null && _current.Id == organization.Id)
            {
                // Push Parent Up the Hierarchy if not reference to self
                if (organization.Id != parent.Id)
                {
                    parent.Parent = _current.Parent;
                    _current.Parent = parent;
                }
                // Return null to indicate not at the top of the Hierarchy
                return null;
            }
            // Save the current Organization
            var prev = _current;
            // Setup the new Organization Parent if not null
            _current = organization;

            if (organization.Id != parent.Id)
                _current.Parent = parent;

            // Return the now populated previous Organization (or null if first time through)
            return prev;
        }
    }
}