Snapping another layer point with Create Circle Polygon in Openlayers 2

[balajiputhiran]

I am past one week trying this but still can't able to achieve this goal.If possible try to sort out my issue as soon as possible.I want to create Circle polygon but i need to take point for my layer vertex point in using snapping.I don't know how to do ? When i am click on the map the create polygon circle has to be create automatically snapping on my layer vertex point

How to do ?I am using Openlayers 2