Find a Closed Wire on a Plane in an Edge Set

Hellow,(您好！,this is "Hellow" in my native language LOL)

I'm a student, working on a CAD-like project. I try to add an edge to the scene, in which there are some edges and faces. The new edge may create a new closed wire on a plane. How can I find the new closed wire? Is there a handy API-Tool in OCC? Must I use graph algorithm, such as DFS, to find?

Thanks in advance.