Multi-way Dataflow Constraint Propagation in Real-time Collaborative Systems

Constraints are very useful in real-time collaborative editing systems. They are able to automatically enforce semantic rules and properties. A specific type of constraint is dataflow constraint. Any property that can be expressed as an equation can be represented as a dataflow constraint. However, ensuring multi-way dataflow constraint satisfaction and consistency maintenance in a replicated collaborative environment is a challenge. This paper presents a novel method for computing multi-way dataflow constraint propagation for real-time collaborative editing systems. This method produces convergent result that is consistent with syntax level effect, irrespective of the operation execution order. This method is generic and is applied to enforce object placement and label name consistency in a realtime collaborative CASE system