ISE%20582:%20Web%20Technology%20for%20Industrial%20Engineering

1
ISE 582 Web Technology for Industrial Engineering

• University of Southern California
• DJE Dept of Industrial and Systems Engineering

Lecture 7
JAVA Cup 7 Its all in the Packaging
2
Handouts

• Lecture 7 slides
• READ Winston Narasimhan
• Chapters 33-38 (pp 201-233)

3
JAVA Cup 7

• Characters and Strings
• Codestrings and delimiters
• How to Read/Write Objects
• How to Modularize Programs
• Creating a Window

4
Specifying Delimiters

• You can use codestrings to specify interesting
  information in textfile

5
Specifying Delimiters

• To advise the tokens tokenizer to use double
  quotation marks to delimit strings
• tokens.quoteChar((int) )
• To tell the tokenizer to recognize carriage
  returns
• tokens.eolIsSignificant(true)

6
Working with O/p File Streams

• To connect to output file
• FileOutputStream stream new FileOutputStream(ou
  tput.data)
• To write more than 1-byte-at-a-time
• PrintWriter writer new PrintWriter(stream)
• Its good to flush out buffered characters
• writer.flush()
• Close the file
• stream.close()

7
Reading / Writing Objects

• Serialized input-output operations
• ltobj.o/p.streamgt.writeObject(ltvectorgt)
• ltobj.i/p.streamgt.readObject()
• Indicate intentions to use operations by
• implements Serializable
• throws IOException, ClassNotFoundException
• Each instance must belong a class that implements
  the Serializable Interface

8
Review
stream
writer
9
Reading Objects from File

• FileInputStream fileInputStream
• new FileInputStream(in.data)
• ObjectInputStream objectInputStream
• new ObjectInputStream(fileInputStream)
• Vector ltvectorgt
• (Vector) objectInputStream.readObject()

10
To Write Objects to File

• FileOutputStream fileOutputStream new
  FileOutputStream(out.data)
• ObjectOutputStream objectOutputStream new
  ObjectOutputStream(fileOutputStream)
• objectOutputStream.writeObject(ltvectorgt)
• objectOutputStream.close()

11
Modularing Your Program

• Compilation Units
• Packages
• Setting CLASSPATH
• Calling Methods from a Module
• Access to Var/Methods in Package

12
Compilation Units

• Define all classes in same file
• Only one class can be public
• Only one class is universally accessible
• Convention each class has its own compilation
  unit

13
Packages

• Use single-class compilation units
• Indicate module using package statement at
  beginning of each c.u
• package onto.java.entertainment
• Convention package names consist of components
  separated by dots

14
CLASSPATH

• Package names correspond to paths
• package onto.java.entertainment
• Files stores in ./onto/java
• Setting the path
• setenv CLASSPATH ltpath1gtltpath2gt.
• setenv CLASSPATHltpath1gtltpath2gt.

UNIX
PC
15
Using Methods from a Package

• First import package
• import onto.java.entertainment.
• Auxiliaries.readMovieFile(input.data)
• ((Movie) vectorElement).rating()
• Or, refer to entire name
• onto.java.entertainment.Auxiliaries.readMovieFile
  (input.data)
• ((onto.java.entertainment.Movie)
  vectorElement).rating()

16
Access to Variables/Methods

• private
• available only to methods inside own class
• protected
• available to methods in same class, c.u. or
  package, subclasses
• No keyword
• available only to c.u. or package

17
How to Create Windows

• Nomenclature
• Intro to Swing classes
• Hierarchy of Swing classes
• Listener Classes
• Window Creation Pattern

18
Nomenclature

• GUI (pronounced goo-ey)
• Graphical User Interface
• Components
• class instances that have a graphical
  representation
• Containers
• components that allow nesting of other containers
  inside their boundaries
• Window
• a containers graphical representation

19
Introduction to Swing (J) Classes

• API Application Programmers Interface
• The AWT Package java.awt.
• AWT Abstract Window Toolkit
• contains Component, Container classes
• The Swing Package java.swing.
• contains JFrame, JApplet, JComponent, JPanel
  classes
• Try to restrict display work to Swing classes

20
Hierarchy of Swing Classes
21
Example A Window

• import javax.swing.
• public class Demonstrate
• public static void main (String argv )
• JFrame frame new JFrame (I am a window,
  square and proud)
• frame.setSize(200,200)
• frame.show()

22
Listener Classes

• Event as a state change
• Mouse clicks and key presses
• Variable-value changes
• Event as instance of EventObject class
• Describes state change
• Java deals with events through Listener Classes
• Listener classes are defined by
• Extending existing listener classes
• Implementing listener interfaces

23
Example Link listener to frame

• When mouse clicks
• a WindowEvent instance is created
• the windowClosing method is called with connected
  listener as target and WindowEvent instance as arg

24
Adapter Classes

• Adapter classes implement all interface-required
  methods as do-nothing methods.
• You can define shadowing methods in your subclass
  for whatever subset of methods you need

25
Nesting Class Definitions

• Advantage of nesting classes
• Method definition (windowClosing) appears in
  proximity to window definition
• Can reuse names of private classes such as
  LocalWindowListener

26
Window Creation Pattern

• Define a subclass of JFrame class
• Main method calls constructor
• Constructor
• assigns title, size, and displays a window
• creates required class instances
• connects class instances