Socketbased Printer Server Application Example

1
Socket-based Printer Server Application Example
Celsina Bignoli bignolic_at_smccd.net
2
The Application

• makes a printer available over the network via a
  socket-based API

Server
Client
Printer
network
local connection

• makes a User Interface available to the user
• gets print requests
• sends requests to the Server

• receives print requests from the client
• performs any necessary intermediate task
• forwards requests to the printer

3
Basic Objects - Printer

• public interface Printer extends PrinterConstants
• public boolean printerAvailable()
• public boolean printDocument(DocumentDescription
  
• document) throws
  PrinterException
• public class PrinterException extends Exception
• private int _numberOfPages
• private String _errorDescription

4
Basic Objects - Document

• public class DocumentDescription
• public static final int FAST_PRINTING 0
• public static final int HIGH_QUALITY_PRINTING1
  
• public static final int POSTCRIPT0
• public static final int PDF1
• private DataInputStream _actualDocument
• private int _documentType
• private boolean _printTwoSided
• private int _printQuality
• private int _length

5
The Protocol

• The client sends an instance of
  DocumentDescription to the server
• The Server sends back a response indicating
  weather the document was successfully printed
• connection between client and server is closed
• See printer application code, chapter 3

6
Application Architecture
Client
Server
User Interface
Client Network Wrapper
Server Network Wrapper
Implem. Printer Interface
network
Printer
7
New Features

• More than one printer
• Print Queue
• Scalability
• Tracking resource consumption

8
Code Changes

• Mostly to deal changes in the protocol
• add new methods
• more marshalling/demarshalling of objects
• Versioning issues