Hi @Bob_Obara, as I am reviewing the worklet MR, I am becoming more sure that smtk::resource::Component should not have a schema and version. If components are going to mirror BRep-like model entities, that would be a lot of overhead; the resource’s schema should cover its components. What makes smtk::project::Project different is that we are proposing users be allowed to exchange component “definitions” (worklets in the task gallery).
However, if we want to support other components using the same mechanism we do for worklets, we need a way to add support independent of inheritance (we already use inheritance for other purposes).
Alternative 1: Schema via property
What if we used the property mechanism to annotate components that need a schema+version number? Instead of having smtk::task::Worklet provide ivars for a schema and version number, what if we provided
namespace smtk { namespace resource {
struct Schema
{
public:
smtk::string::Token m_name;
int m_version;
bool operator <(const Schema& other);
bool operator <=(const Schema& other);
};
}} // namespaces
and added it to the default property types that resources provide? This allows any subset of components to be marked with a schema.
Alternative 2: Schema as a component
Another alternative would be to create a new component type:
namespace smtk { namespace resource {
class Schema : public smtk::resource::Component
{
public:
Schema();
Schema(smtk::string::Token name, int version);
std::string name() const override;
smtk::string::Token schemaName() const;
int schemaVersion() const;
protected:
smtk::string::Token m_name;
int m_version;
};
}} // namespaces
and use links to connect instances of the schema to components. We could then add API to either resources or even persistent objects to provide a Schema (or null):
namespace smtk { namespace resource {
class PersistentObject
{
public:
/// Return an indicator of the data format and version of this object.
/// This may return null.
virtual Schema* schema() { return nullptr; }
};
}} // namespaces
deprecate the smtk::attribute::Resource::templateType() and templateVersion() API.