Distributed Real-time Collaborative Text Editing System Realization

Recently, CSCW, as an important research area in computer science, develops rapidly and obtains more and more notice from the public. This thesis is about real-time cooperative text editing system, which is a branch of CSCW research. To design real-time cooperative editing system we must resolve many technique problems, especially to maintain consistency of the shared document under edit when concurrent operation is present. This thesis proposes a novel consistency maintenance mechanism-the FOPT consistency maintenance algorithm-based on previous research on concurrent control, and builds a plug-in for Eclipse. The plug-in can be used to support distributed virtual pair programming. The FOPT algorithm includes three parts: casual order preservation, Folding Operation Transformation scheme (FOPT) and garbage collection. We use a well-known technique based on State Vector for casual preservation. The method uses State Vector to capture casual order relation between operations and govern that only operations those are casual ready can be dispatched to transform and execute.The FOPT scheme, which is the focus of our research, is used to preserve user intension and convergence. The main idea of FOPT is to maintain a mapping relation between document and operation history buffer through proper organization of the history buffer, and to resolve concurrency conflicts by employing a Hide/Resume scheme. The garbage collection part removes operations that are independent of the FOPT scheme to reduce memory footprint.The design and development of the cooperative editing plug-in for Eclipse is another emphasis we focus on. We explore design and implementation consideration of the system from several perspectives: communication layer, session management, cooperative awareness, consistency maintenance and integration with Eclipse. We choose Jabber as the communication platform and design a reliable transport over it. Session management is important to organize collaboration among a group of people. We propose a session management protocol based on initiator. This protocol can...