Meta Model Definition Code (Origam.Schema)

tvavrda · June 3, 2025, 9:36am

All model elements are defined inside Origam.Schema namespace. Every model element derives from ISchemaItem.

Model Hierarchy

The way how to get child elements of any model element or even a category of model elements is using the interface ISchemaItemFactory and its method public Type[] NewItemTypes.

So one way to see what elements can be created under the current element is to see NewItemTypes

github.com/origam/origam

backend/Origam.Schema.WorkflowModel/SchemaItems/Service.cs

4b6983ac6


      
          	private string _classPath;
          	[XmlAttribute("classPath")]
          	public string ClassPath
          	{
          		get => _classPath;
          		set => _classPath = value;
          	}
          	#endregion
          	#region ISchemaItemFactory Members
          	[Browsable(false)]
          	public override Type[] NewItemTypes => new[]
          	{
          		typeof(ServiceMethod)
          	};
          	public override T NewItem<T>(
          		Guid schemaExtensionId, SchemaItemGroup group)
          	{
          		return base.NewItem<T>(schemaExtensionId, group, 
          			typeof(T) == typeof(ServiceMethod) ?
          				"NewServiceMethod" : null);
          	}

In this case Service has an only possible child ServiceMethod.

In some more recent code NewItemTypes property is not overridden and in such a case either there are no child items available or there is another piece of code (typically living in an Init() method) that fills in ChildItemTypes collection like this:

github.com/origam/origam

backend/Origam.Schema.EntityModel/AbstractDataEntity.cs

4b6983ac6


      
          [ClassMetaVersion("6.0.0")]
          public abstract class AbstractDataEntity : AbstractSchemaItem, IDataEntity, ISchemaItemFactory
          {
          	public AbstractDataEntity() : base() {Init();}
          	public AbstractDataEntity(Guid schemaExtensionId) : base(schemaExtensionId) {Init();}
          	public AbstractDataEntity(Key primaryKey) : base(primaryKey)	{Init();}
          	public const string  CategoryConst = "DataEntity";
          	private void Init()
          	{
          		this.ChildItemTypes.InsertRange(0,
          			new Type[] {
          						   typeof(FieldMappingItem),
          						   typeof(DetachedField),
          						   typeof(FunctionCall),
          						   typeof(AggregatedColumn),
          						   typeof(LookupField),
          						   typeof(EntityRelationItem),
          						   typeof(DatabaseParameter),
          						   typeof(EntityFilter),
          						   typeof(DataEntityIndex),
          						   typeof(EntitySecurityFilterReference),

In this case any data entity can have the following children:

Database Field
Virtual Field
Function Field
Aggregated Field
Lookup Field
Relationship
Parameter
Filter
Index
Row Level Security Filter
Row Level Security Rule
Conditional Formatting Rule

Root Model Elements

Every root model element lives inside ISchemaItemProvider.

github.com/origam/origam

backend/Origam.Schema/StringSchemaItemProvider.cs

4b6983ac6


      
          
          You should have received a copy of the GNU General Public License
          along with ORIGAM. If not, see <http://www.gnu.org/licenses/>.
          */
          #endregion
          
          using System;
          
          
          namespace Origam.Schema;
          public class StringSchemaItemProvider : AbstractSchemaItemProvider
          {
          	public StringSchemaItemProvider() {}
          	
          	#region ISchemaItemProvider Members
          	public override string RootItemType => StringItem.CategoryConst;
          	public override string Group => "COMMON";
          	#endregion
          	#region IBrowserNode Members
          	public override string Icon =>
          		// TODO:  Add EntityModelSchemaItemProvider.ImageIndex getter implementation

Every provider has a property Group which denotes the group of providers. Currently we have the following provider groups:

Common
Data
User Interface
Business Logic
API