Layered document model transformation and operation adaptation of two dimensional CAD environments

Transparent Adaptation (TA) technology is a strategy to transform single-user applications into groupware system without modifying the original source codes. There are two key issues of TA technology: data model transformation and operation adaptation. The paper introduces to map the two dimensional CAD document into layered document model, modifies AST consistency maintenance strategy to layer-AST to adapt to the new model; gives primitive operation definitions in CAD environments, and uses application APIs to capture the interface operations. Efficiency analysis of the layer-AST is also given, showing the improved performance of the algorithm.