A part of my modelis a bit modified Composite pattern:

NativeDatapoint ----|>  Datapoint     CalculatedDatapoint ----|>  Datapoint 

CalculatedDatapoint *-----* Datapoint.

The only difference as you see is m:n association instead of n:1

I need to define a derived attribute int Ranque on Datapoint with the following meaning: it should contain the longest path over the association links from this instance to one of the leafs (instance of the class NativeDatapoint). I accept only OCL-solutions

I have to less time now to try it myself. One tip: Ranque for NativeDatapoint is always 0.

/Efim

Thanks a lot, Pete, you are master of Recursion Sciences

/Efim

I totally misread the question and thought you needed the max path between a CalcDataPoint instance and a specific NativeDataPoint instance - not just any NativeDataPoint.

I thought I'd share my solution anyway if anyone ever needs it.  This will find the maximum path length between any two objects (of the same inheritance that share the association) linked by a many to many association.  Easily changed to shortest path if required.

Call it in ocl with   startingObjectInstance.MaxPathLengthTo(endObjectInstance, 'AssociationNameAsString')

ie - NativeDataPointInstance.MaxPathLengthTo(CalcDataPointInstance, 'DataPoints')

Nick

public class LongestPath : OclOperationBase
{
public IObject startingObject;
public IObject endObject;
public string assoication;
public List<int> pathLengths;
public int FindLongestPath ()
{
pathLengths = new List<int>();
foreach (IObject associatedObject in startingObject.Properties[assoication].GetAsCollection())
{
TraverseObjects(associatedObject, 1, new List<IObject>());
}
pathLengths.Sort();
return pathLengths[pathLengths.Count - 1];
//return pathLengths[0]; //returns shortest rather than longest path
}
public void TraverseObjects ( IObject obj, int pathLengthToObject, List<IObject> traveresedObjects )
{
if (obj == endObject)
{
pathLengths.Add(pathLengthToObject);
}
else
{
foreach (IObject associatedObject in obj.Properties[assoication].GetAsCollection())
{
if (!traveresedObjects.Contains(associatedObject))
{
traveresedObjects.Add(associatedObject);
TraverseObjects(associatedObject, pathLengthToObject + 1, traveresedObjects);
}
}
}
}
public override void Evaluate ( IOclOperationParameters oclParameters )
{
startingObject = oclParameters.Values[0].Element as IObject;
endObject = oclParameters.Values[1].Element as IObject;
assoication = Support.GetAsString(oclParameters.Values[2]);
int result = FindLongestPath();
Support.MakeNewInteger(oclParameters.Result, result);
}
protected override void Init ()
{
IOclType[] oclParameters = new IOclType[3];
oclParameters[0] = Support.ObjectType;
oclParameters[1] = Support.ObjectType;
oclParameters[2] = Support.StringType;
InternalInit("MaxPathLengthToObject", oclParameters, Support.IntegerType);
}
}