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Слайды и текст к этой презентации:
№1 слайд
Содержание слайда: Internet and Java
Foundations, Programming and Practice
№2 слайд
Содержание слайда: Agenda
Internet and its Evolution
Internet Tools
Web and its Programming
Java for Internet Programming
Java Nuts and Bolts
Java Platform
Developing Applets and Applications
Challenges and Future Directions
№3 слайд
Содержание слайда: What is the Internet ?
№4 слайд
Содержание слайда: Internet Technology Evolution
Internet is much bigger than what we think
More than 25 years old
More than doubling every year
Technology effect
suddenly every body sees the need for a technology
like the radio or the TV
10 terabytes flows everyday
№5 слайд
Содержание слайда: Internet
Use of internet advertisement/elections/newspapers
information is public
Ubiquitous technology
Network is the computer
Intranets - internal TCP/IP nets
PC accounts for 55% of total IT
Applications tied to platform - API lock-in
№6 слайд
Содержание слайда: Internet Evolution
№7 слайд
Содержание слайда: Early Internet
Early Internet supported only email .
File Transfer Protocol development - ftp sites.
Network News was added to the Internet.
Archie - A program to canvass anonymous ftp sites and create a database of what is available
Gopher- A menu-driven interface used to search for information.
Archie and Gopher could answer questions only like ‘what FTP server contains info about “xxxx” ‘
№8 слайд
Содержание слайда: World Wide Web
World Wide Web conceptualized by Tim Berners-Lee at CERN in Switzerland
Concept of Hypertext led to the development of the Hypertext Markup Language (HTML)
Tim Berners-Lee proposed the ‘Browser’ program
Scientists at CERN designed a TCP/IP based protocol to share Hypertext information called HTTP.
WWW officially is described as a” Wide-area hypermedia information retrieval initiative aiming to give universal access to a large universe of documents.
№9 слайд
Содержание слайда: HTML
Hypertext -A little Hype and a Little Text.
Hypertext point to information which can be local or remotely located.
HTML -Derivative of the SGML( Standard Generalized Markup Language).
HTML -information , commands for the Browser for formatting documents.
HTML -The de-facto language for publishing on the Internet.
Hypermedia- Hyper-links to Multimedia.
№10 слайд
Содержание слайда: Internet Tools
Browsers- A tool used to view documents on the WWW
Web servers - Machines which run the HTTP-server Software that respond to HTTP requests which it receives
Authoring Tools - Editors specially made for editing HTML documents
Filters -Tools to convert legacy documents to HTML format
Scripting -Languages used for scripting
WAIS- Wide Area Information Servers (WAIS) for indexing and doing full text searches
№11 слайд
Содержание слайда: How does the Web work ?
Web -Designed around Client/Server Architecture
Web Clients ( Web Browsers ) -send requests for documents to any Web Server
Web Server -Program that responds to HTTP requests
Hyperlink
Web client connects to the specified Web Server
The server responds by sending the information asked for
The Browser formats the received HTML data and displays it
№12 слайд
Содержание слайда: How does the Web Work
№13 слайд
Содержание слайда: HTML document
<HTML>
<TITLE>Centre for Development of Advanced Computing
</TITLE>
<BODY BGCOLOR=“#E7CCCC” TEXT=“#000000” LINK=“#0000FF”>
...
...
<A HREF=“mailto:webmaster@cdacb.ernet.in> webmaster</A>
</BODY>
</HTML>
№14 слайд
Содержание слайда:
№15 слайд
Содержание слайда: URLs
URLs- The Hypertext links we use today are known as Universal Resource Locator
URLs-Each name is unique across the Internet
An URL looks like this
http://system.domain.ext:999/dir1/dir2/dir3/file.html?blue#
Parts of a URL are,
Service type, System Name, Port, Directory path, Filename,Search Components or Variables
Service type, System Name, Directory path are the required parts of the URL
№16 слайд
Содержание слайда: CGI (Common Gateway Interface)
CGI makes the Web a Two-way interface
CGI -lets the user run a script when a web page is accessed
Information from the Web Client is received through simple ‘fill-in-the-forms’ kind of interface
FORMS - Integrates data sheets, menus , check boxes
CGI makes the Web interactive
CGI -complicated to setup ,requires PERL knowledge
HTML books talk less about CGI
№17 слайд
Содержание слайда: Authoring tools and Filters
Authoring tools- Editors for HTML documents
Editors similar to WYSIWYG word processing programs
Semi-WYSIWYG or completely WYSIWYG
Provide syntax checking and correction
Filters -Convert legacy documents to HTML format
Filters are useful when the documents already exist
Authoring tools- HoTMetaL, HTML Assistant -Shareware
№18 слайд
Содержание слайда: Preconfigured v/s Integrated Internet Products
Integrated Internet Products- From multiple vendors
Preconfigured Systems- Web Server and a Client ready to use
Sun’s Netra Internet Server
SGI’s WebFORCE Indy and WebFORCE Challenge S
Apple’s Internet Server Solution
DEC’s Internet AlphaServer
Integraph’s Web Server 10
№19 слайд
Содержание слайда: Future Directions
Additions to HTML (Grammar, Maths, Display control)
VRML (Virtual Reality Markup Language)
Security - Using Scrambling and Encryption
Common Client Interface (CCI)- Allows Clients to pass information back and forth between the Browser and the External Viewer
Charge Mechanisms
Performance Enhancements- Sending a page and graphics for that page in one connection
№20 слайд
Содержание слайда: Interesting URLs
http://www.whitehouse.gov ( The WhiteHouse)
http://www.w3.org (Everything about the WWW)
http://sunsite.unc.edu (Software on Sun)
http://www.indnet.org (India Net Foundation Services)
telnet://www.arbornet.org (Free Public Access Unix System)
http://www.infoseek.com (Search engines, Add URL)
http://www.infophil.com (World Alumni on the net)
http://www.rocketmail.com (Free Email )
http://members.tripod.com (Free Website,2MB space)
http://www.bangaloreonline.com (Offers virtual web servvices for compinies to host their website).
http://www.prajavani.com (Kannada news paper on web)
№21 слайд
Содержание слайда: API Bottleneck
№22 слайд
Содержание слайда: The OS - Platform lock
№23 слайд
Содержание слайда: The Web
№24 слайд
Содержание слайда: Making life easier!
Data on the web
Browser platform independent
Click on application - run on any machine
Java the programming language of the 21 century
№25 слайд
Содержание слайда: Java and Java Computing
№26 слайд
Содержание слайда: Java - An Introduction
Java - The new programming language from Sun Microsystems
Java -Allows anyone to publish a web page with Java code in it
Java - CPU Independent language
Created for consumer electronics
Java - James , Arthur Van , and others
Java -The name that survived a patent search
Oak -The predecessor of Java
Java is “C++ -- ++ “
№27 слайд
Содержание слайда: Java From 10,000 Ft.
According to the world, Java is...
According to Sun, Java is...
On closer inspection, Java is
№28 слайд
Содержание слайда: According to the World, Java Is...
Snazzy Web pages
The cross-platform language we want
The rest-of-the-worlds answer to Bill
The C++ replacement we need
The C++ replacement we dont need
A bunch of hype
№29 слайд
Содержание слайда: According to Sun, Java is...
Simple and Powerful
Object Oriented
Portable
Architecture Neutral
Distributed
Multi-threaded
Robust, Secure/Safe
Interpreted
High Performance
Dynamic pogramming language/platform.
№30 слайд
Содержание слайда: On Closer Inspection, Java is...
Simple
Pure
Portable
Surprisingly effective
№31 слайд
Содержание слайда: As a whole, Java is a Comprehensive Programming Solution
Object Oriented
Portable
High Performance
Geared for Distributed Environments
Secure
№32 слайд
Содержание слайда: Java as Object Oriented
“Objects all the way down”
Simple and Familiar: “C++ Lite”
No Pointers!
Garbage Collector
Dynamic Binding
Single Inheritance with “Interfaces”
№33 слайд
Содержание слайда: Java as Portable
Unlike other language compilers, Java complier generates code (byte codes) for Universal Machine.
Java Virtual Machine (JVM): Interprets bytecodes at runtime
Architecture Neutral
No Link Phase
Higher Level Portable Features: AWT, Unicode
№34 слайд
Содержание слайда: Total Platform Independence
№35 слайд
Содержание слайда:
№36 слайд
Содержание слайда: Architecture Neutral & Portable
Java Compiler -Java source code to bytecode
Bytecode - an intermediate form, closer to machine representation
A virtual machine on any target platform interprets the bytecode
Porting the java system to any new platform involves writing an interpreter that supports the Java Virtual Machine
The interpreter will figure out what the equivalent machine dependent code to run
№37 слайд
Содержание слайда: Java as High Performance
JVM uses “lean and mean” bytecodes
Small binary class filtes
Just-in-time Compilers
Multithreading
Native Methods
№38 слайд
Содержание слайда: Java in the World of Distributed Computing
Class Loader
Lightweight Binary Class Files
Multithreading
Dynamic
Good communication constructs
Secure
№39 слайд
Содержание слайда: Java as Secure
Language designed as safe
Strict compiler
Dynamic Runtime Loading (Verifier)
Runtime Security Manager
№40 слайд
Содержание слайда: Object Oriented Languages -a Comparison
№41 слайд
Содержание слайда: Java better than C++ ?
No Typedefs, Defines, or Preprocessor
No Global Variables
No Goto statements
No Pointers
No Unsafe Structures
No Multiple Inheritance
No Operator Overloading
No Automatic Coercions
No Fragile Data Types
№42 слайд
Содержание слайда: Basic Data Types
Types
boolean either true of false
char 16 bit Unicode 1.1
byte 8-bit integer (signed)
short 16-bit integer (signed)
int 32-bit integer (signed)
long 64-bit integer (singed)
float 32-bit floating point (IEEE 754-1985)
double 64-bit floating point (IEEE 754-1985)
String (class for manipulating strings)
Java uses Unicode to represent characters internally
№43 слайд
Содержание слайда: Java Integrates
Power of Compiled Languages
and
Flexibility of Interpreted Languages
№44 слайд
Содержание слайда: Two Types of JavaApplications
Different ways to write/run a Java codes are:
Application- A stand-alone program that can be invoked from command line . A program that has a “main” method
Applet- A program embedded in a web page , to be run when the page is browsed . A program that contains no “main” method
Application -Java interpreter
Applets- Java enabled web browser (Linked to HTML via <APPLET> tag. in html file)
№45 слайд
Содержание слайда:
№46 слайд
Содержание слайда: Java Development Kit
javac - The Java Compiler
java - The Java Interpreter
jdb- The Java Debugger
appletviewer -Tool to run the applets
javap - to print the Java bytecodes
javaprof - Java profiler
javadoc - documentation generator
javah - creates C header files
№47 слайд
Содержание слайда: Hello Internet
// hello.java: Hello Internet program
class HelloInternet
{
public static void main(String args[])
{
System.out.println(“Hello Internet”);
}
}
№48 слайд
Содержание слайда: Program Processing
Compilation
# javac hello.java
results in HelloInternet.class
Execution
# java HelloInternet
Hello Internet
#
№49 слайд
Содержание слайда: Simple Java Applet
// HelloWorld.java: A sample applet
import java.applet.Applet;
public class HelloWorld extends Applet {
public void paint(Graphics g)
{
g.drawString(“Hello World !”,25,25);
}
}
№50 слайд
Содержание слайда: Calling an Applet
<HTML>
<TITLE> Hello Worls Applet </TITLE>
<APPLET code=“HelloWorld.class” width=500 height=500>
</APPLET>
</HTML>
№51 слайд
Содержание слайда: Execution of Applets
№52 слайд
Содержание слайда: Web Perspective
How did Web interactions work?
How do they work with Java?
Distributed Java objects and the Web
№53 слайд
Содержание слайда: Classical Web Perspective
№54 слайд
Содержание слайда: Java Web Perspective
№55 слайд
Содержание слайда: Significance of downloading Applets
Interactive WWW
Flashy animation instead of static web pages
Applets react to users input and dynamically change
Display of dynamic data
WWW with Java - more than a document publishing medium
http://www.javasoft.com/applets/alpha/applets/StockDemo/standalone.html
№56 слайд
Содержание слайда: Power of Java and the Web
Deliver applications, not just information
Eliminate porting
Eliminate end-user installation
Slash software distribution costs
Reach millions of customers - instantly
№57 слайд
Содержание слайда: Lifecycle of Java Code
№58 слайд
Содержание слайда: Bytecode Verifier
Called when class is first loaded in runtime environment
Verifies bytecodes meet certain set of properties
Verifier uses Theorem Prover
Verified code runs faster
After verification, interpreter defines memory layout
№59 слайд
Содержание слайда: Class Loader
Unique “Namespace” for each origin
Local namespace classes are called “built-ins”
Prevents class “spoofing”
№60 слайд
Содержание слайда: Security Manager
Prevents unauthorized disk read/writes
Restricts network access
Other access restrictions (native methods)
Implementation is browser dependent
№61 слайд
Содержание слайда: General Language Features
C/C++ like syntax
No pointers
Objects all the way down
Objects request services of other objects through messages
Messages result in invocation of class methods
№62 слайд
Содержание слайда: Removed From C++
Operator overloading
Pointers and Array/pointers
Multiple-inheritance of implementation
Enum, typedef, #define
Copy constructors, destructors
Templates
And other stuff....
№63 слайд
Содержание слайда: Added or Improved over C++
Interfaces: type Vs. class
Garbage collection
Exceptions (More powerful than C++)
Strings
Instanceof
Package
Multi-threads
№64 слайд
Содержание слайда: Rich Object Environment
Core Classes
language
Utilities
Input/Output
Low-Level Networking
Abstract Graphical User Interface
Internet Classes
TCP/IP Networking
WWW and HTML
Distributed Programs
№65 слайд
Содержание слайда: Main Packages
java.lang
java.util
java.io
java.awt
java.awt.image
java.applet
java.net
№66 слайд
Содержание слайда: Java Fundamentals
Constructs
Graphics
Multithreading
Streams and Networking
Networking
№67 слайд
Содержание слайда: Unit I--Java Constructs
what is Java, basic constructs, including
classes and objects
constructors,
this and super keywords,
inheritance,
abstract classes, interfaces,
inner classes,
exceptions.
№68 слайд
Содержание слайда: Unit II--Graphics Programming
How to build Graphical User Interfaces in Java:
GUI components,
event handling,
layout management.
№69 слайд
Содержание слайда: Unit III--Advanced Features
Applets,
Threads,
Streams I/O,
Networking
№70 слайд
Содержание слайда: Unit I -- What is Java ?
A programming language:
Object oriented (no friends, all functions are members of classes, no function libraries -- just class libraries)
simple (no pointer arithmetic, no need for programmer to deallocate memory)
platform independent
dynamic
interpreted
№71 слайд
Содержание слайда: Types
Eight basic types
4 integers (byte, short, int, short) [ int a; ]
2 floating point (float, double) [ double a;]
1 character (char) [ char a; ]
1 boolean (boolean) [ boolean a; ]
Everything else is an object
String s;
№72 слайд
Содержание слайда: Classes and objects
declaring a class
class MyClass {
member variables;
…
member functions () ;
…
} // end class MyClass
№73 слайд
Содержание слайда: Java programs
Two kinds
Applications
have main()
run from the OS prompt
Applets
have init(), start(), stop(), paint(), update(), repaint(), destroy()
run from within a web page
№74 слайд
Содержание слайда: The first Java Application
class MyApp {
public static void main(String s [ ] ) {
System.out.println(“Hello World”);
}
} // end class MyApp
№75 слайд
Содержание слайда: Declaring and creating objects
declare a reference
String s;
create/define an object
s = new String (“India”);
№76 слайд
Содержание слайда: Arrays (are objects in Java)
declare
int a [ ] ; // 1-dim
int [ ] b ; // 1-dim
int [ ] c [ ]; // 2-dim
int c [ ][]; // 2-dim
allocate space
a = new int [7];
c = new int [7][11];
№77 слайд
Содержание слайда: Arrays have length
used to retrieve the size of an array
int a [ ] = new int [7]; // 1-dim
System.out.println(a.length); will print ‘7’
int b [ ] [ ] = new int [7] [11];
System.out.println(a.length); will print ‘7’
System.out.println(b.length * b[0].length); will print ‘77’
№78 слайд
Содержание слайда: … this is because
Let int [][][][] array = new int [7][11][10][21] , then …
array.length * array[3].length * array[3][5].length * array[3][5][2].length is 7 x 11 x 10 x 21
№79 слайд
Содержание слайда: … this is because
№80 слайд
Содержание слайда: Constructors
All objects are created through constructors
They are invoked automatically
class Weight {
int lb; int oz;
public Weight (int a, int b ) {
lb = a; oz = b;
}
}
№81 слайд
Содержание слайда: this keyword
refers to “this” object (object in which it is used)
usage:
with an instance variable or method of “this” class
as a function inside a constructor of “this” class
as “this” object, when passed as parameter
№82 слайд
Содержание слайда: this :: with a variable
refers to “this” object’s data member
class Weight {
int lb; int oz;
public Weight (int lb, int oz ) {
this.lb = lb; this.oz = oz;
}
}
№83 слайд
Содержание слайда: this :: with a method
refers to another method of “this” class
class Weight {
public int m1 (int a) {
int x = this.m2(a); return x;
}
public int m2(int b) { return b*7 ; }
}
№84 слайд
Содержание слайда: this :: as a function inside a constructor of “this” class
must be used with a constructor
class Weight {
int lb, oz;
public Weight (int a, int b) { lb = a; oz = b; }
}
public Weight (int x) { this( x, 0); }
}
№85 слайд
Содержание слайда: this :: as “this” object, when passed as parameter
refers to the object that used to call the calling method
class MyApp {
int a;
public static void main(String [] s ) { (new MyApp()).myMethod(); }
public void myMethod() { yourMethod(this); }
public void yourMethod(MyApp inMyApp) { inMyApp.a = 77; }
}
№86 слайд
Содержание слайда: static keyword
means “global”--all all objects refer to the same storage.
applies to variables or methods”
usage:
with an instance variable of a class
with a method of a class
№87 слайд
Содержание слайда: static keyword (with variables)
class PurchaseOrder {
private static int POCount; // var. ‘a’ is shared by all objects of this class
public static void main(String [] s ) {
PurchaseOrder po1 = new PurchaseOrder();
po1.updatePOCount();
}
public void updatePOCount() { POCount++; }
}
№88 слайд
Содержание слайда: static keyword (w/ methods)
№89 слайд
Содержание слайда: Inheritance (subclassing)
№90 слайд
Содержание слайда: Manager can be made a sub/derived-class of Employee
№91 слайд
Содержание слайда: Overriding (methods)
№92 слайд
Содержание слайда: class First {
public First() { System.out.println(“ First class “); }
}
public class Second extends First {
public Second() { System.out.println(“Second class”); }
}
public class Third extends Second {
public Third() {System.out.println(“Third class”);}
}
№93 слайд
Содержание слайда: access modifiers
private
same class only
public
everywhere
protected
same class, same package, any subclass
(default)
same class, same package
№94 слайд
Содержание слайда: super keyword
refers to the superclass (base class)
usage:
with a variable or method (most common with a method)
as a function inside a constructor of the subclass
№95 слайд
Содержание слайда: super :: with a method
class Manager extends Employee {
private double bonus;
public void setBonus(double bb) { …}
public void raise(double dd) { //overrides raise() of Employee
super.raise(dd); // call Employee’s raise()
salary += bonus;
}
public Manager ( … ) { … }
}
№96 слайд
Содержание слайда: super :: as a function inside a constructor of the subclass
class Manager extends Employee {
private double bonus;
public void setBonus(double bb) { …}
public Manager ( String name, double salary, double bonus ) {
super(name, salary);
this.bonus = bonus;
}
}
№97 слайд
Содержание слайда: final keyword
means “constant”
applies to
variables (makes a var. constant), or
methods (makes a method non-overridable), or
classes (makes a class non-subclassable means “objects cannot be created”).
№98 слайд
Содержание слайда: final keyword with a variable
class Math {
public final double pi = 3.1412;
public static double method(double x) {
double x = pi * pi;
}
}
note: variable pi is made “read-only”
№99 слайд
Содержание слайда: final keyword with a method
№100 слайд
Содержание слайда: final keyword with a class
№101 слайд
Содержание слайда: abstract classes and interfaces
abstract classes
may have both implemented and non-implemented methods
interfaces
have only non-implemented methods
(concrete classes)
have all their methods implemented
№102 слайд
Содержание слайда: sample abstract class
№103 слайд
Содержание слайда: sample interface
№104 слайд
Содержание слайда: Exceptions (error handling)
№105 слайд
Содержание слайда: Exceptions (cont’d)
№106 слайд
Содержание слайда: methods throwing exceptions
№107 слайд
Содержание слайда: Defining your own exceptions
№108 слайд
Содержание слайда: GUI Programming in Java
(AWT and Event Handling)
№109 слайд
Содержание слайда: AWT - Abstract Windowing Toolkit
Single Windowing Interface on Multiple Platforms
Supports functions common to all window systems
Uses Underlying Native Window system
AWT provides
GUI widgets
Event Handling
Containers for widgets
Layout managers
Graphic operations
№110 слайд
Содержание слайда: AWT - Abstract Window Toolkit
Portable GUI - preserves native look & feel
Standard GUI Components (buttons…)
Containers - Panels, Frames, Dialogs
Graphics class for custom drawing
Layouts responsible for actual positioning of components:
BorderLayout, GridLayout, FlowLayout, null layoit
№111 слайд
Содержание слайда: Adding Components via Layouts
setLayout(new BorderLayout());
// Add text field to top
add("North",new TextField());
// Create the panel with buttons at the bottom...
Panel p = new Panel(); // FlowLayout
p.add(new Button("OK"));
p.add(new Button("Cancel"));
add("South",p);
№112 слайд
Содержание слайда: Adding Components via Layouts
№113 слайд
Содержание слайда: Building Graphical User Interfaces
import java.awt.*;
Assemble the GUI
use GUI components,
basic components (e.g., Button, TextField)
containers (Frame, Panel)
set the positioning of the components
use Layout Managers
Attach events
№114 слайд
Содержание слайда: A sample GUI program
№115 слайд
Содержание слайда:
№116 слайд
Содержание слайда: Events
№117 слайд
Содержание слайда: Events
Each GUI component (e.g., a Button) that wishes to respond to an event type (e.g., click), must register an event handler, called a Listener.
The listener is an object of a "Listener" interface.
A Listener class can be created by subclassing (through "implements") one of Listener interfaces (all listener inrefaces are in the java.awt.event package = > must import java.awt.event.*; )
The registration of the listener is done by a call to a method such as addActionListener(<Listener Object>). Each GUI component class has one or more such add…() methods, where applicable.
№118 слайд
Содержание слайда: Listener Interfaces
№119 слайд
Содержание слайда: Listener Interfaces
№120 слайд
Содержание слайда: 1) windowActivated(WindowEvent) - Invoked when a window is activated.
2) windowClosed(WindowEvent) - Invoked when a window has been closed.
3) windowClosing(WindowEvent) - Invoked when a window is in the process of being closed.
4) windowDeactivated(WindowEvent) - Invoked when a window is de-activated.
5) windowDeiconified(WindowEvent) - Invoked when a window is de-iconified.
6) windowIconified(WindowEvent) - Invoked when a window is iconified.
7) windowOpened(WindowEvent) - Invoked when a window has been opened.
№121 слайд
Содержание слайда: How to create an object of a listener interface ?
№122 слайд
Содержание слайда: Implementing the ActionListener Interface
and attaching an event handler to a button
№123 слайд
Содержание слайда: class MyApp implements ActionListener, WindowListener {
Button b = new Button(“OK”);
Frame f = new Frame(“My Frame”);
public static void main(String [] s ) {(new MyApp()).go(); }
public void go() {
b.addActionListener( this );
f.addWindowListener( this );
}
public void actionPerformed(ActionEvent e ) { … }
public void windowActivated(WindowEvent e ) { … }
public void windowClosed(WindowEvent e ) { … }
public void windowClosing(WindowEvent e ) { … }
public void windowDeactivated(WindowEvent e) { … }
public void windowDeiconified(WindowEvent e) { … }
public void windowIconified(WindowEvent e) { … }
public void windowOpened(WindowEvent e) { … }
}
№124 слайд
Содержание слайда: or … use Adapters
№125 слайд
Содержание слайда: But, we can only use one Adapter at a time (no multiple inheritance)
№126 слайд
Содержание слайда: However … can use inner classes instead !!!
№127 слайд
Содержание слайда: Popup Menu and Event Handling...
//popup.java: popup menu and event handling
import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
public class popup extends Frame implements ActionListener, MouseListener
{
TextField text1;
PopupMenu popup;
MenuItem menuitem1, menuitem2, menuitem3;
public popup()
{
super( "Popup Menu" );
setLayout(new FlowLayout());
setBounds(10, 10, 300, 200 );
setVisible(true);
init();
}
public void init()
{
popup = new PopupMenu("Resource Usage" );
№128 слайд
Содержание слайда: Popup Menu and Event Handling...
menuitem1 = new MenuItem("CPU");
menuitem1.addActionListener(this);
menuitem2 = new MenuItem("Disk");
menuitem2.addActionListener(this);
menuitem3 = new MenuItem("Memory");
menuitem3.addActionListener(this);
popup.add(menuitem1);
popup.add(menuitem2);
popup.add(menuitem3);
add(popup);
text1 = new TextField(20);
text1.setBounds(20, 40, 120, 30 );
add(text1);
addMouseListener(this);
}
public void mousePressed(MouseEvent e )
{
if( e.getModifiers() != 0 )
popup.show(this, e.getX(), e.getY() );
}
№129 слайд
Содержание слайда: Popup Menu and Event Handling
public void mouseReleased( MouseEvent e )
{ System.out.print("Mouse Released\n" ); }
public void mouseEntered( MouseEvent e )
{ System.out.print("Mouse Entered\n" ); }
public void mouseExited( MouseEvent e )
{ System.out.print("Mouse Exited\n" ); }
public void actionPerformed( ActionEvent e )
{
if( e.getSource() == menuitem1 )
{ text1.setText("CPU"); }
if( e.getSource() == menuitem2 )
{ text1.setText("Disk"); }
if( e.getSource() == menuitem3 )
{ text1.setText("Memory"); }
}
public static void main( String args[] )
{
popup p = new popup();
}
}
№130 слайд
Содержание слайда: Applets and GUI
№131 слайд
Содержание слайда: AWT & Applets
№132 слайд
Содержание слайда: Applet methods
AppletContext
“Applet” derived from AWT Panel
Hooks into Browser environment
Can be used to link to another Web page
№133 слайд
Содержание слайда: A sample Applet
// HelloApplet.java: for processing applet methods
import java.awt.*;
import java.applet.*;
public class HelloApplet extends Applet
{
public void init() {
setBackground(Color.yellow);
System.out.println("init() method invoked");
}
public void start()
{
System.out.println("start() method invoked");
}
public void paint( Graphics g )
{
System.out.println("paint() method invoked");
g.drawString( "Hi there", 24, 25 );
}
public void stop()
{
System.out.println("stop() method invoked");
}
}
№134 слайд
Содержание слайда: sample Applet
№135 слайд
Содержание слайда: another sample Applet (run in Applet Viewer)
№136 слайд
Содержание слайда: sample Applet
running within Netscape
№137 слайд
Содержание слайда: sample Applet code
№138 слайд
Содержание слайда: Another example
// MyApplet.java: draws rectangle with yellow color fill
import java.applet.*;
import java.awt.*;
public class MyApplet extends Applet
{
public synchronized void paint(Graphics g)
{
int x,y,width,height;
Dimension dm = size();
x = dm.width/4;
y = dm.height / 4;
width = dm.width / 2;
height = dm.height / 2;
// Draw the rectangle in the center with colors!
g.setColor(Color.blue);
g.drawRect(x,y,width,height);
g.setColor(Color.yellow);
g.fillRect(x + 1,y + 1,width - 2,height - 2);
}
}
№139 слайд
Содержание слайда: order of Applet method execution
№140 слайд
Содержание слайда: order of Applet method execution (cont’d)
№141 слайд
Содержание слайда: Incorporating Images and sound in Applets
№142 слайд
Содержание слайда: sample Applet with sound
№143 слайд
Содержание слайда: how to do that ….
№144 слайд
Содержание слайда: Applet that displays image
№145 слайд
Содержание слайда: Applet that plays sound
№146 слайд
Содержание слайда: Multithreading in Java
(A built-in feature in Java)
№147 слайд
Содержание слайда: Single and Multithreaded Processes
№148 слайд
Содержание слайда: Threads
Java has built in thread support for Multithreading
Synchronization
Thread Scheduling
Inter-Thread Communication:
currentThread start setPriority
yield run getPriority
sleep stop suspend
resume
Java Garbage Collector is a low-priority thread
№149 слайд
Содержание слайда: Thread states
№150 слайд
Содержание слайда: Threading Mechanisms...
Create a class that extends the Thread class
Create a class that implements the Runnable interface
№151 слайд
Содержание слайда: 1st method: Extending Thread class
1st Method: Extending the Thread class
class MyThread extends Thread
{
public void run()
{
// thread body of execution
}
}
Creating thread:
MyThread thr1 = new MyThread();
Start Execution:
thr1.start();
№152 слайд
Содержание слайда: An example
№153 слайд
Содержание слайда: 2nd method: Threads by implementing Runnable interface
class MyThread implements Runnable
{
.....
public void run()
{
// thread body of execution
}
}
Creating Object:
MyThread myObject = new MyThread();
Creating Thread Object:
Thread thr1 = new Thread( myObject );
Start Execution:
thr1.start();
№154 слайд
Содержание слайда: An example
№155 слайд
Содержание слайда: A program with two threads
№156 слайд
Содержание слайда: Monitor model (for Syncronisation)
№157 слайд
Содержание слайда: examples :: program with two threads and shared object
№158 слайд
Содержание слайда: the monitor (shared object)
№159 слайд
Содержание слайда: the driver
№160 слайд
Содержание слайда: Threads in Action...
Cooperative threads - File Copy
№161 слайд
Содержание слайда: Streams and I/O
№162 слайд
Содержание слайда: Streams and I/O
basic classes for file IO
FileInputStream, for reading from a file
FileOutputStream, for writing to a file
Example:
Open a file "myfile.txt" for reading
FileInputStream fis = new FileInputStream("myfile.txt");
Open a file "outfile.txt" for writing
FileOutputStream fos = new FileOutputStream ("myfile.txt");
№163 слайд
Содержание слайда: Display File Contents
№164 слайд
Содержание слайда: Filters
№165 слайд
Содержание слайда: Writing data to a file using Filters
№166 слайд
Содержание слайда: Reading data from a file using filters
№167 слайд
Содержание слайда: Object serialization
№168 слайд
Содержание слайда: Write an object to a file
№169 слайд
Содержание слайда: Read an object from a file
№170 слайд
Содержание слайда: Network/Socket Programming in Java
№171 слайд
Содержание слайда: java.net
Used to manage:
URL streams
Client/server sockets
Datagrams
№172 слайд
Содержание слайда: Part III - Networking
№173 слайд
Содержание слайда: Server side Socket Operations
1. Open Server Socket:
String server; Socket slink;
DataOutputStream os;
DataInputStream is;
server = new ServerSocket( PORT );
2. Wait for Client Request:
Socket client = server.accept();
3. Create I/O streams for communicating to clients
is = new DataInputStream( client.getInputStream() );
os = new DataOutputStream( client.getOutputStream() );
4. Perform communication with client
Receiive from client: String line = is.readLine();
Send to client: os.writeBytes("Hello\n");
5. Close sockets: client.close();
For multithreade server:
while(true) {
i. wait for client requests (step 2 above)
ii. create a thread with “client” socket as parameter (the thread creates streams (as in step (3) and does communication as stated in (4). Remove thread once service is provided.
}
№174 слайд
Содержание слайда: Client side Socket Operations
1. Get connection to server:
client = new Socket( server, port_id );
2. Create I/O streams for communicating to clients
is = new DataInputStream( client.getInputStream() );
os = new DataOutputStream( client.getOutputStream() );
3. Perform communication with client
Receiive from client: String line = is.readLine();
Send to client: os.writeBytes("Hello\n");
4. Close sockets: client.close();
№175 слайд
Содержание слайда: A simple server (simplified code)
№176 слайд
Содержание слайда: A simple client (simplified code)
№177 слайд
Содержание слайда: Echo Server Client..
//client.java: client interface to server
import java.io.*;
import java.net.*;
public class client
{
int port_id;
String server; Socket slink;
DataOutputStream os;
DataInputStream is;
DataInputStream kbd;
public client( String args[] )
{
server = args[0];
port_id = Integer.valueOf(args[1]).intValue();
try
{
slink = new Socket( server, port_id );
os = new DataOutputStream( slink.getOutputStream() );
is = new DataInputStream( slink.getInputStream() );
kbd = new DataInputStream( System.in );
}
№178 слайд
Содержание слайда: Echo Server Client..
catch( UnknownHostException e )
{
System.err.println( "Don't know about host: " );
System.exit(1);
}
catch( IOException e )
{
System.err.println( "Could not get I/O for the connection to "+server);
System.exit(1);
}
}
void communicate()
{
while(true)
{
try {
System.out.print("Enter Input <end to stop>: ");
String line = kbd.readLine();
os.writeBytes( line+"\n" );
№179 слайд
Содержание слайда: Echo Server Client..
if( line.equals("end") )
{ os.close(); is.close(); slink.close();
break;
}
String line2 = is.readLine();
System.out.println("Output: "+line2);
}
catch( IOException e )
{ System.out.println(e); }
}
}
public static void main( String [] args )
{
if( args.length < 2 )
{
System.out.println("Usage: java client server_name port_id" );
System.exit(1);
}
client cln = new client( args );
cln.communicate();
}
}
№180 слайд
Содержание слайда: Echo Server ...
// server.java: echo server
import java.io.*;
import java.net.*;
public class server
{
// public final static int PORT = 4779;
public static void main( String [] args )
{
ServerSocket server = null;
DataOutputStream os = null;
DataInputStream is = null;
boolean shutdown = false;
if( args.length < 1 )
{
System.out.println( "Usage: java server port_num" );
System.exit( 1 );
}
int PORT = Integer.valueOf(args[0]).intValue();
try {
server = new ServerSocket( PORT );
}
№181 слайд
Содержание слайда: Echo Server ...
catch( IOException e )
{
System.err.println( "Could not get I/O for the connection to: ");
}
while(!shutdown)
{
if( server != null )
{
try
{
Socket client = server.accept();
System.out.println("Connected");
InetAddress cip = client.getInetAddress();
System.out.println( "Client IP Addr: "+cip.toString());
is = new DataInputStream( client.getInputStream() );
os = new DataOutputStream( client.getOutputStream() );
for(;;)
{
String line = is.readLine();
if( line == null )
break;
№182 слайд
Содержание слайда: Echo Server ...
if( line.startsWith("end" ) )
{
shutdown = true;
break;
}
os.writeBytes(line.toUpperCase());
os.writeBytes("\n");
System.out.println(line);
}
is.close(); client.close();
}
catch( UnknownHostException e )
{
System.err.println( "Server Open fails" );
}
catch( IOException e )
{
System.err.println( "Could not get I/O for the connection to:"+args[0]);
}
}
}
№183 слайд
Содержание слайда: Echo Server
System.out.println( "Server Down" );
try {
server.close();
} catch(IOException e) {}
}
}
№184 слайд
Содержание слайда:
№185 слайд
Содержание слайда: Java System Architecture & Availability
№186 слайд
Содержание слайда: A Look Inside the Java Platform
№187 слайд
Содержание слайда: Java Applications!
Java applications are now available
Cost of manfg zero, cost of distribution zero, cost of marketing zero!
Hot Java is lean - loads everything else from the net.
Java itself is small - 40k to 225k
New class of small machines will emerge
Java on cellular phones, credit cards, washing machines, and everywhere ?
№188 слайд
Содержание слайда: Universal Interface
№189 слайд
Содержание слайда: Java on my platform ?
Sun (SPARC) ftp://java.sun.com
Sun(x86) ftp://xm.com:/pub/
IBM(Aix, OS/2)ftp://ncc.hursley.ibm.com/javainfo
DEC(Alpha OSF/1) http://www.gr.osf.org:8001/projects/web/java/
SGI http://liawww.epfl.ch/~simon/java/irix-jdk.html
HP http://www.gr.osf.org:8001/projects/web/java
Linux http://www.blackdown.org
AT & T http://www.gr.osf.org:8001/projects/web/java
Windows 3.1 http://www.alphaworks.ibm.com
№190 слайд
Содержание слайда: Java Development Tools
(Present and Planned)
№191 слайд
Содержание слайда: Sun’s Java WorkShop
JDK:
Compiler and runtime environment
Class Libraries
Documentation
javadoc - Automated Documentation
Takes comments and converts to HTML
IDE: Visual Java, and integrated tools, JavaBeans
Other Products and API: JavaHelp, Java Card, Java Blend, JavaOS, Java Mail, Java Management, Java Electronic Commerce Framework
Java Enterprise API: Java Naming and Directory Interface, Java IDL, JDBC, RMI and Object Serialization
№192 слайд
Содержание слайда: Symantec Cafe 1.0 (Released)
Full IDE for Windows 95/NT
Graphic Development Tools
Two Compilers
Debugger
Class Browser
№193 слайд
Содержание слайда: Microsoft Jakarta (Planned)
Visual C++ type interface
Will Support ActiveX/COM
Internet Explorer 3.0 will have Just-In-Time Java compiler
№194 слайд
Содержание слайда: Borland JBuilder
Visual RAD workbench for maximum productivity.
Rapid Application Development (RAD) and Open Component Architecture patterned after Delphi.
100+ JavaBean components, with source code, for drag-and-drop applications.
Beans Express--easiest way to create industry-standard Java-Bean components.
DataExpress -- the fastest way to build business and database appplications.
Borland DataGateway for Java connectivity to all major database servers.
Multi-tier applications with integrated RMI and CORBA.
Versions: Standard, Professional, & Client/Server
№195 слайд
Содержание слайда: Challenges & Possible Directions
Performance
AWT - need better GUI!
Maintaining Interoperability
Security - current restrictions limit what can be done
Native Compilers
Is Portability that Important?
№196 слайд
Содержание слайда: Comments
Java is a fun and easy programming language
Portability = Mediocrity?
Java will become a programming language of choice, but may take on a final form that will surprise many!
№197 слайд
Содержание слайда: JDBC
Java API for Relational Databases
Being standardized by all major players
№198 слайд
Содержание слайда: Javascript and Java (Preview)
Javascript can control Java applets
Static data accessible as properties of applet
var i = Bank.Account.count
Public methods invocable on Java instances
Provided those instances are accessible through the Applet
Applet is accessible through document
document.applet_Name_Attribute.do_Stuff()
№199 слайд
Содержание слайда: Java for HPC!
Many efforts are in in progress for making java as a language for parallel programming.
Java computing frameworks (HPC, numeric, data parallel)
Java in distributed simulations and applications (e.g., real-world HPC, grand chalenge)
Source to source translators (C, Fortran, C++ to Java)
Web based computation environment in Java
Java for HPC conference: http://www.cs.ucsb.edu/conferences/java98
Java for Science and Engineering computing: subscribe java-for-cse to majordomo@npac.syr.edu
http://www.jhpc.org
№200 слайд
Содержание слайда: How to Convert Programs to AWT 1.1...
1. Change source code so that it import event package:
import java.awt.event.*;
2. Figure out which component generates each event type: (1.0 uses handleEvent() and action())
Button, List, MenuItem, TextField:
Interface: ActionListener
Method: actionPerformed(ActionEvent event)
Checkbox, CheckboxMenuItem, Choice:
Interface: ItemListener Method: itemStateChanged(..)
Dialog, Frame:
Interface: WindowListener
Method: windowClosing(), windowOpened(),...
№201 слайд
Содержание слайда: How to Convert Programs to AWT 1.1...
3. Change class declaration so that class implements
public class MyClass extends SomeComponent
implements ActionListener
4. Register action Listener
newComponentObject.addActionListener(this);
5. Change event handling method:
Old: public boolean action(Event e, Object arg)
New: public void actionPerformed(ActionEvent e)
№202 слайд
Содержание слайда: How to Convert Programs to AWT 1.1
6. Delete the event handling code in this way
(a) Delete all return statements
(b) Change e.target to e.getSource()
(c) Delete all code the unnecessarily tests for which
component the event come from
(d) Perform any other modification require to make
the program compile
№203 слайд
Содержание слайда: Just to Summarize
Java as a Comprehensive Programming Solution
Object Oriented
Portable
High Performance
Geared for Distributed Environments
Secure
Highly suitable for Internet programming
№204 слайд
Содержание слайда: Summary
Java is really very well poised
Incredible leverage from the Web
Will impact the C++ and Smalltalk markets
Rate of progress is astonishingly high
Development environments
CORBA linkages
Components
Fasten you seat-belts!
№205 слайд
Содержание слайда:
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