ProCol

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ProCol A jEdit Plugin for Remote Project
Collaboration Justin Dieters Spring
2004 CS470 Final Presentation
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What is ProCol?

• Plugin for the jEdit text editor
• Facilitates on-line collaboration between
  developers
• Small groups (2-10 people)
• Small to medium sized projects
• Provides file repository, users are able to check
  out files
• Provides communication and project management
  functions
• Quick and easy to set up and use
• Current solutions - CVS, SourceForge, gForge,
  etc.
• Complex to set up
• Time-consuming to maintain
• Not practical for small projects

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Requirements

• Not developed for a specific client
• Requirements developed by looking at existing
  solutions
• Possible improvements
• Past experience
• Scope of project was fairly large
• Open-ended requirements
• Goal Release usable beta version by end of class
• Development continued as an open-source software
  project (GPL)
• Able to be extended by others
• Clients for other development environments
• Web-based clients

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Client Requirements

• Compact and simple graphical interface
• Able to integrate well with jEdit's user
  interface
• Complex functionality in separate dialog windows
• File tree
• Indicate checkout status with bold text
• Get information about individual files
• User list
• Windows for file transfer, messaging, etc
• Able to be docked
• Project snapshot

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Server Requirements

• Handles multiple simultaneous connections from
  clients
• Uses SSL sockets for security
• Information stored on disk in properties files
• Readable by the Java Properties class
• Do not need separate database
• Java uses hash tables for this
• Maintain project and user information
• Simple configuration files
• Store versioning/changelog information for each
  file
• Store communication and project management
  messages
• Automatic file backup
• Accidental or malicious deletion/changes

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Plugin Interface
Options
Connect
Help
Project Info
Change Project
File Tree
Checked-out File
Popup Menu
Upload file/directory
New file/directory
Snapshot
User List
Private Messages
Bug List
Public Messages
Todo List
Progress Bar
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Connecting to Server
Connect
Login
Join Project
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File Management
File Info
File Check-in
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Communication Tools
Reading messages
Composing a message
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Project Management Tools
Bug List
Posting a New Bug
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Docked Windows
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Client Architecture
GUI
Model
Dockable Windows
Project
Message Composers
User
Misc. Dialogs
Messages
Sections communicate using Observer/Observable
pattern
Network
ProColClient
Communication to Server
Communication from Server
IncomingMessageHandler
OutgoingMessageHandler
MessageFactory
PacketFactory
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Server Architecture
Model
Projects
Users
ServerConnection maintains reference to currently
opened project
ProColServer
Network
ServerConnection
Communication to Client
Communication from Client
IncomingMessageHandler
OutgoingMessageHandler
MessageFactory
PacketFactory
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Network Protocol
Data (0 to 2032 bytes)
Header (16 bytes)
messageID
requestType
dataRemain
dataSize
Data Section
Packet (2048 bytes max)

• Messages are broken into packets of maximum 2048
  bytes
• 16 byte header followed by optional data section
• Allows low priority messages to be interrupted to
  send high priority message
• Less than 1 overhead per packet for full data
  section
• PacketFactory class generates packets to be sent
• Data can be drawn from Strings, byte arrays,
  files, etc
• Automatically determines which packet to send
  next based on priority
• MessageFactory class reassembles packets into
  original messages
• Handed off to Observers for handling

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What Worked?

• Networking
• Spent large percentage of time developing
  networking
• Packets and priority queues
• Anonymous SSL security
• Open, easy protocol, able to be used by other
  ProCol clients/servers
• Dockable windows
• Integrate well with jEdit
• Able to use as normal window or docked
• Store settings in Properties files
• Labels, buttons, error messages, etc
• Central location for changes, applied throughout
  program

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What Did Not Work?

• NIO (New I/O)
• Java's new I/O API
• Good in theory, bad in implementation
• Many problems in Sun's code that I was unable to
  work around
• 2 weeks wasted with troubleshooting and rewriting
• Rewrote large portions of networking code to
  revert back to classic networking
• Too many features
• Not enough time to implement everything I wanted
• All required features implemented, but some are
  rather basic

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Conclusion

• Was project successful?
• Yes, all requirements satisfied
• Proved usable during testing
• Interest expressed by jEdit community
• Will be released under GPL
• May continue development
• What did I learn?
• Java features SSL, NIO, Threads, Properties
• Implementing design patterns Observer, MVC,
  Factory
• jEdit Plugin programming, Beanshell scripting
• Apache Ant automated compiling and packaging

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Questions? Justin Dieters Spring
2004 CS470 Final Presentation