CS 4773 Object Oriented Systems, Spring 2005 Project Overview

Editor model: A computer system, mainly OS file management

Editor:

• Either the main class or one created by the main class
• Keeps track of all files being edited (EditorFile)
• Each file has one or more editing sessions (EditingSession)
• When there are no more editing sessions, the file is removed.
• Responsibility: OpenEditingSession(String filename)
  Creates a new EditorFile if one does not exist for this filename
  Creates a new EditingSession for this EditorFile
• Responsibility: CloseEditingSession
  Removes an EditingSession and the corresponding EditorFile if there are no more editing sessions for this one.
• Think of this as a file management system for an operating system.

• This corresponds to a memory image of a file
• Constructor takes a filename and reads in the correponding file
• Each has one or more editing sessions (EditingSession)
• Responsibilities include: getItem, replaceItem, appendItem, insertItem, etc.
• Responsible for synchronizing access from multiple editing sessions
• Responsible for saving the file when done
• Think of this as an "inode".
  There is only one of these for each real file.
• We will assume that the entire file can be read into memory.
  Otherwise, we can model this as a virtual memory system.

• This contains an EditorFile and a cursor position.
• May also keep track of a range of items being displayed
• Has a thread for executing commands (CommandThread)
• Has an input user interface for inserting commands (UserInput)
• Has an output user interface for displaying results (UserOutput)
• Think of this as a "System File Table Entry".
  Several of these may use the same inode.

• Has an EditingSession
• Responsibility: insert command
• Think of this as a file descriptor open for reading

• Has an EditingSession
• Responsibility: a single item has changed
• Responsibility: a list of items have changed
• Responsibility: all items changed
• Responsibility: report an error to the user
• Think of this as a file descriptor open for writing

• Responsible for executing commands
• Should be able to handle command strings, raw commands and macro commands
• Maintains a queue of commands to execute
• Has support for a macro processor
• Uses a CommandDecoder to decode a command string into a raw command
• Think of this as a CPU performing an instruction cycle:
  fetch, increment PC, decode, execute, handle interrupts
  This has to be done in the context of a multiple CPU system
  (multiple EditingSessions have multiple CommandThreads)

• This is like a subroutine of commands
• Creator takes the name of a file containing commands
• Responsibile for returning the next command to execute.

• Responsible for taking a command string and converting it to a raw command.

• Has a CommandExecuter
• Has an CommandIdentifier
• Has the command parameters
• Responsibility: execute itself by calling the appropriate method in the CommandExecuter

• Responsible for the execution of a collection of CommandIdentifiers

• This sits on top the the entire editing system and allows the user to examine what is going on.
• List all EditFiles, EditingSessions, CommandThreads
• Trace a CommandThread
• Trace a UserInput
• Trace a UserOutput
• Suspend and resume operation of a CommandThread or all CommandThreads
• Examine the macro stack of an CommandThread
• Abort a macro
• Produce printable logs

• Has a UserInput
• Has a UserOutput
• Has an Inspector

Prepare an index card containing the following:

1. Your name
2. Parts of the project you would like to work on
3. Parts of the project you would like to avoid
4. Class members you would like to work with in a group
5. Class members you would like to avoid working with
   This will be kept confidential.

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