Advanced Java Book

7/25/2019 Advanced Java Book

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Advanced Java Programming


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Version 1999First Impression August 1999

Second Impression July 2000

The Team

Production / Series SupervisionJambu Krishnamurthy

Vice President Product Development

The HeadSridhar SubramaniamHead Training Solutions

Technical WritersThirumurugan .R

Bakkia Lakshmi .H

Uma .S

Review

Sridhar Subramaniam

Production/DesignVijay. V

EditorNurjehan Dhanani

Copyright1999, Comp-U-Learn Inc.

All Rights Reserved

No Part of this Book may be reproduced in any form by any means, stored in a retrieval system, or transmitted by any mode,

electronic, mechanical, photocopying, recording, or otherwise, without written permission from the publisher. Exceptions aremade to the program listings, which can be typed, stored in a Computer System and executed. No patent liability is assumed

with respect to the use of the information contained herein. Although every precaution has been taken in the preparation of this

book, the publisher assumes no responsibility for errors or omissions. Neither is any liability assumed for damages resulting

from the use of the information contained herein.

All Trade Marks Acknowledged


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The Book at a Glance


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Table of Contents


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III. Index ....................................................................................................... 291


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i

Before We Begin

This beginning, a solid, stable one, will take the reader to greater heightsin Programming for the Web and the Internet. Mainly Java. Lets begin.....

The phenomenon is waiting.


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ii

How to use this Book


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iii

Objectives of this Book

Conventions Used in this Book

Each session is divided into 12 topics. It is called the Twelve Point

Program (12pp). In every session, these points are distinctly shown in

an underlined bigger font.

Subheadings appear in bold without underlining.

Note is shown inside a box. It is information which is necessary to

understand the subject discussed but does not come as a part of the text

flow.

Summary is at the end of each session, shown in a special table,

italicized.

Each session ends with a Going Over It Again. This helps the student

in recapitulating the session contents. Figure numbers and descriptions are given below each picture, diagram

or screen for proper navigation.


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Session 1

Swing in Java

On Completion of this Session you will be able to understand...

Introduction to JFC

Swing and their behavior

Merits and Demerits of Swing

Programming in Swing

Using Tables and Image ListsUsing Geometric Figures in Swing


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In This Session...

Introduction to Java Foundation Classes

Introduction to Swing

The Swing Component Hierarchy

An Overview of Swing Packages

Moving along with Swing

Swing Button

Slider Control and Progress Bar

Image List

Tables

Drawing Objects

JscrollBar

JRadioButton


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Swing in Java

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Introduction to Java Foundation Classes

The Abstract Windowing ToolKit

Swing

Java 2D

Drag and Drop Accessibility

Introduction to Swing


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Comp-U-Learn4

Swing components are independent of the native windowing system.

They can run on any windowing system that supports the AWT.

Swing provides a pure Java implementation of many of the traditional AWTcomponents.

Swing is compatible with the AWT and Swing components can be usedinterchangeably with AWT components.

The number and quality of the GUI controls provided by Swing is unrivaled byany other GUI toolkit.

Swing has a very rich collection and user friendly set of interface elements.

Swing gives a consistent user experience across platforms.

Swing has the capability of making Sun Microsystemss dream of Write once,run anywhere come to reality.

Swing-based user interface elements are somewhat slower to appear on the usersscreen than the peer based components used by the AWT.

Since the user interface elements look almost alike on all platforms, they will

look different from the native controls on at least some platforms, and thus userswill be less familiar with them.

Swing components can be used only with the JDK 1.1 event model. They dontsupport JDK 1.0 event model.

The Swing Component Hierarchy


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Swing in Java

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Comp-U-Learn6

An Overview of Swing Packages

Thecom.sun.java.swing.plafprovides support for Swings pluggable look and feel features.


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Swing in Java

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JCheck BoxMenuIte mJMenuJRadioButton MenuItem

JButtonJMenuIte m

JChech BoxJRadioButton

JToggleButton

AbstractButton

DefaultTableCellRendere r(java.awt.swing.table)

JLabel

JI nte rnalFram eJC om boB ox

JDesk topPane

JLayeredPane

JL istJM enuBarJO ption Pane

ColorChooserPane

JP anel

JP op upMenuJP rogressBarJR ootPaneJS crollB arJS crollPaneJS eparatorJS liderJS plitPaneJTabbedPaneJTableJTableHeader(java .awt.sw ingn.table )

JTe xtPane

JEd itorPane

JPasswordFie ld

JTe xtFie ld

JTe xtarea

JTextCom pon ent(java .a wt.sw ing.text)

JToolB arJToolTipJTreeJV ie wPor t

JCom ponent


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Comp-U-Learn8

Moving along with Swing

Example 1.1:

import javax.swing.*;

class frame extends JFrame

{

public frame()

{

setTitle(Our First Frame);

setSize(300,200);

}

}

public class framedemo

{

public static void main(String args[]){

JFrame fr=new frame();

fr.show();

}

}

Fig. 1.1


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Swing in Java

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Example 1.2:

import javax.swing.*;import java.awt.event.*;class frame extends JFrame{

public frame(){setTitle(Sample Frame);setSize(300,200); addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) { System.exit(0); } });}}

public class framedemo{

public static void main(String args[]){JFrame fr=new frame();fr.show();}}

Fig 1.2


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Example 1.3:


import java.awt.*;

import java.awt.event.*;

class ourpanel extends JPanel{

public void paintComponent(Graphics g)

{

super.paintComponent(g);

g.drawString(Welcome to Swing,100,80);

}

}

class ourframe extends JFrame

{

public ourframe()

{

setTitle(Sample Frame Window);setSize(300,500);

addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{

System.exit(0);


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Swing in Java

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}

});

Container con=getContentPane();

con.add(new ourpanel());

}

}

public class welcome

{

public static void main(String args[])

{

JFrame fr=new ourframe();

fr.show();

}

}

Fig. 1.3

Swing Button

Example 1.4:

import java.awt.*;



import javax.swing.event.*;

import javax.swing.border.*;


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Comp-U-Learn12

class swing extends Frame

{

JTabbedPane tabbedPane = new JTabbedPane();

JPanel buttonPanel = new JPanel();

JPanel[] panels = {buttonPanel};

Icon worldIcon = new ImageIcon(Dbmusic.gif);

Icon printerIcon = new ImageIcon(Eatdrink.gif);

JButton printerButton = new JButton(Print,printerIcon);

JToggleButton worldButton = new

JToggleButton(Connect,worldIcon,true);

public swing()

{

super(Swing Button window);

addWindowListener(new WindowHandler());

String[] tabs = {Buttons};

String[] tabTips = {A Button and a Toggle Button};

for(int i=0;i


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Fig 1.4

Slider Control and Progress Bar


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Example 1.6:

import java.awt.*;




import javax.swing.border.*;

public class list extends Frame {

JTabbedPane tb = new JTabbedPane();

JPanel lpanel = new JPanel();

JPanel[] panels = {lpanel};

Icon i1 = new ImageIcon(videos.gif);

Icon i2 = new ImageIcon(school.gif);

Icon i3 = new ImageIcon(invntory.gif);

Icon i4 = new ImageIcon(members.gif);

Icon[] leaves = {i1, i2, i3, i4};

JList mylist = new JList(leaves);

public list() {

super(List Box Display);


String[] tabs = {Icon List};

String[] tabTips = {An Image List Control};

mylist.setFixedCellHeight(100);

lpanel.add(mylist);

for(int i=0;i


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public static void main(String args[]) {

list l = new list();

}

public class WindowHandler extends WindowAdapter { public void windowClosing(WindowEvent e) {

System.exit(0);

}

}

}

Fig. 1.6

Tables


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Fig. 1.7

Drawing Objects

Example 1.8:

import java.awt.*;

import java.awt.event.*;import javax.swing.*;

class shapes extends JPanel {

public void paintComponent(Graphics g) {

super.paintComponent(g);


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g.setColor(Color.blue);

g.drawRect(20,30,100,70);

g.drawLine(180,220,300,270);

g.drawRoundRect(140,40,80,50,15,15);

g.drawOval(30,120,100,40);

Polygon p = new Polygon();p.addPoint(320,320);

p.addPoint(320,390);

p.addPoint(400,400);

g.drawPolygon(p);

g.setColor(Color.orange);

g.fillRect(320,30,100,70);

g.fillRoundRect(70,220,80,50,15,15);

g.fill3DRect(120,300,100,30,true);

for(int i=1;i


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Example 1.9:

import java.awt.*;



public class ColorSelect extends JFrame implements AdjustmentListener

private JLabel redLabel;

private JLabel greenLabel;

private JLabel blueLabel;

private JScrollBar red;

private JScrollBar green;

private JScrollBar blue;

private JPanel colorPanel;

{ public ColorSelect()

{ setTitle(ColorSelect);

setSize(300, 200);


{ public void windowClosing(WindowEvent e)

{ System.exit(0);

}

} );

Container contentPane = getContentPane();

JPanel p = new JPanel();

p.setLayout(new GridLayout(3, 2));

p.add(redLabel = new JLabel(Red 0));

p.add(red = new JScrollBar(Adjustable.HORIZONTAL,

0, 0, 0, 255));

red.setBlockIncrement(16);

red.addAdjustmentListener(this);

p.add(greenLabel = new JLabel(Green 0));

p.add(green = new JScrollBar(Adjustable.HORIZONTAL,

0, 0, 0, 255));

green.setBlockIncrement(16);

green.addAdjustmentListener(this);

p.add(blueLabel = new JLabel(Blue 0));

p.add(blue = new JScrollBar(Adjustable.HORIZONTAL,

0, 0, 0, 255));

blue.setBlockIncrement(16); blue.addAdjustmentListener(this);

contentPane.add(p, South);

colorPanel = new JPanel();

colorPanel.setBackground(new Color(0, 0, 0));

contentPane.add(colorPanel, Center);

}


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public void adjustmentValueChanged(AdjustmentEvent evt)

{ redLabel.setText(Red + red.getValue());

greenLabel.setText(Green + green.getValue());

blueLabel.setText(Blue + blue.getValue());

colorPanel.setBackground(new Color(red.getValue(),

green.getValue(), blue.getValue()));

colorPanel.repaint();

}

public static void main(String[] args)

{ Frame f = new ColorSelect();

f.show();

}

}

Fig. 1.9

JRadioButton


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Example 1.10:



import java.awt.*;


class radiopanel extends JPanel

{

public radiopanel()

{

setLayout(new GridLayout(4,1));

JRadioButton rb;

ButtonGroup bg=new ButtonGroup();

JLabel l=new JLabel(Ice creams);

l.setFont(new Font(Times New Roman,Font.BOLD,12));

add(l);

rb=new JRadioButton(Vanilla);

add(rb);

bg.add(rb);

rb.setSelected(true);

rb=new JRadioButton(Cassatta);

add(rb);

bg.add(rb);

rb=new JRadioButton(Strawberry);

add(rb);

bg.add(rb);}}

class ourframe extends JFrame

{

public ourframe()

{

setTitle(Sample Frame Window);

setSize(300,500);


{


{System.exit(0);

}

});


con.add(new radiopanel());


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}}

public class Radio

{


{JFrame fr=new ourframe();

fr.show();

}}

Fig 1.10

Summary

In this session, we learnt about the basic concepts of Java Foundation Classes, Swing

components, Swing Component hierarchy and some methods in those classes. We

tried some Swing components like Button, Toggle Button, Slider, Progress Bar, Table

and Image List. Then we also wrote a program, which enabled us to draw some

geometric figures. The difference between AWT and Swing is only a hairline. The

event handling in Swing is the same as in AWT. However, swing provides a rich

source of components and other added features. The major difference lies in theusage of canvas in AWT. Only we can draw on the canvas area. The method paint() is

substituted by paintComponent() in Swings. Here, we can draw on any Swing

Component not essentially on a canvas. We will learn about more Swing components

in the next session.


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Comp-U-Learn26

Going Over It Again

I. Fill in the Blanks

II. State True or False

III. One line Answers


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Swing Components

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ShowMessageDialog Show a message and wait for the user to click OK.

ShowConfirmDialog Show a message and get a confirmation like OK or

Cancel

ShowOptionDialog Show a message and get a user option from a set of

optionsShowInputDialog Show a message and get one line of user input

ERROR_MESSAGE

INFORMATION_MESSAGE

WARNING_MESSAGE

QUESTION_MESSAGE

PLAIN_MESSAGE

String draw the string

Icon show the icon

Component show the component

Object[] Show all objects in the array.

ShowMessageDialog None

ShowConfirmDialog An integer representing the chosen option

ShowOptionDialog An integer representing the chosen option

ShowInputDialog The stringthat the user supplied or selected


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Comp-U-Learn34

OK_OPTION

CANCEL_OPTION

YES_OPTION

NO_OPTION

CLOSED_OPTION

Property Setter Method Getter Method

ICON_PROPERTY setIcon getIcon

INITIAL_SELECTION_VALUE_PR

OPERTY

setInitialSelectionValue getInitialSelectionValue

INITIAL_VALUE_PROPERTY setInitialValue getInitialValue

INPUT_VALUE_PROPERTY setInputValue getInputValue

MESSAGE_PROPERTY setMessage getMessage

MESSAGE_TYPE_PROPERTY setMessageType getMessageType

OPTION_TYPE_PROPERTY setOptionType getOptionTyp

OPTIONS_PROPERTY setOptions getOptionsSELECTION_VALUES_PROPERTY setSelectionValues Get SelectionValue

VALUE_PROPERTY setValue GetValue

WANTS_INPUT_PROPERTY setWantsInput GetWantsInput

Fig. 2.1


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Fig. 2.2

Example 2.1:

import javax.swing.*;public class options extends Object

{public static void main(String args[]){JOptionPane.showMessageDialog(null,Simple Dialog Box);JOptionPane.showMessageDialog(null,Error Dialog Box withtitle,Title,JOptionPane.ERROR_MESSAGE);System.exit(0);}}

Example 2.2:


public class option extends Object

{


{

int result=JOptionPane.showConfirmDialog(null,Continue?,Give

your option,JOptionPane.YES_NO_OPTION);

switch(result)

{


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Comp-U-Learn36

case JOptionPane.YES_OPTION:

System.out.println(Yes Button);

break;

case JOptionPane.NO_OPTION:

System.out.println(No Button);

break;

case JOptionPane.CLOSED_OPTION:

System.out.println(Closed Button);

break;

}

System.exit(0);

}

}

Fig. 2.3

C:\jdk1.2\bin>java option




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Input Dialog Box

Example 2.3:

import javax.swing.*;public class input extends Object{public static void main(String args[]){


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Comp-U-Learn38

String[]flow={Rose,Lilly,Jasmine,Marigold,Tulip,Poppy,Zinna,Dairy};

String ans=JOptionPane.showInputDialog(null,Enter yourName,Test Input,JOptionPane.QUESTION_MESSAGE);

System.out.println(Your name is +ans);

Object sel=JOptionPane.showInputDialog(null,Select from theflowers given,FlowerList,JOptionPane.PLAIN_MESSAGE,null,flow,flow[0]);System.out.println(Your Favourite Flower from selection is+sel);

System.exit(0);

}}

Fig. 2.4

Fig 2.5

C:\jdk1.2\bin>java input


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Fig 2.6

C:\jdk1.2\bin>javac custom.javaC:\jdk1.2\bin>java custom

C:\jdk1.2\bin>java custom

C:\jdk1.2\bin>java custom


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addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } } );

JPanel gridPanel = new JPanel(); gridPanel.setLayout(new GridLayout(2, 3));

typePanel = new ButtonPanel(Type, new String[] { Message, Confirm, Option, Input });

messageTypePanel = new ButtonPanel(Message Type, new String[] { ERROR_MESSAGE,

INFORMATION_MESSAGE, WARNING_MESSAGE, QUESTION_MESSAGE, PLAIN_MESSAGE });

messagePanel = new ButtonPanel(Message, new String[] { String, Icon, Component, Other, Object[] });

optionTypePanel = new ButtonPanel(Confirm, new String[] { DEFAULT_OPTION, YES_NO_OPTION, YES_NO_CANCEL_OPTION, OK_CANCEL_OPTION });

optionsPanel = new ButtonPanel(Option, new String[] { String[], Icon[], Object[]

});

inputPanel = new ButtonPanel(Input, new String[] { Text field, Combo box });


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JPanel showPanel = new JPanel(); JButton showButton = new JButton(Show); showButton.addActionListener(this); showPanel.add(showButton);

gridPanel.add(typePanel); gridPanel.add(messageTypePanel); gridPanel.add(messagePanel); gridPanel.add(optionTypePanel); gridPanel.add(optionsPanel); gridPanel.add(showPanel); gridPanel.add(inputPanel);

Container contentPane = getContentPane(); contentPane.add(gridPanel, Center); contentPane.add(showPanel, South); }

public Object getMessage()

{ String s = messagePanel.getSelection(); if (s.equals(String)) return messageString; else if (s.equals(Icon)) return messageIcon; else if (s.equals(Component)) return messageComponent; else if (s.equals(Object[])) return new Object[] { messageString, messageIcon, messageComponent, messageFont };

else if (s.equals(Other)) return messageFont; else return null; }

public Object[] getOptions() { String s = optionsPanel.getSelection(); if (s.equals(String[])) return new String[] { Yellow, Blue, Red }; else if (s.equals(Icon[])) return new Icon[] { new ImageIcon(icecream.gif), new ImageIcon(peach.gif), new ImageIcon(peas.gif)

}; else if (s.equals(Object[])) return new Object[] { messageString, messageIcon, messageComponent, messageFont


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Fig 2.8

JLabel

Add an Icon

Set the vertical and horizontal position of text relative to Icon

Set the relative position of contents within component

Example 2.6:

import javax.swing.*;import java.awt.*;import java.awt.event.*;

class label extends JPanel{public label(){JLabel l1=new JLabel(Our First label);add(l1);JLabel l2=new JLabel(Our Second Label);Font f=new Font(Times New Roman,Font.BOLD+ Font.ITALIC,20);l2.setFont(f);Icon i=newImageIcon(c:/jdk1.2/demo/jfc/Java2D/images/boat.gif);l2.setIcon(i);

l2.setHorizontalAlignment(JLabel.RIGHT);add(l2);}}

class ourframe extends JFrame{


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public ourframe(){setTitle(Sample Frame Window);setSize(300,500); addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e){

System.exit(0);} }); Container con=getContentPane(); con.add(new label());}}

public class lab{

public static void main(String args[]){JFrame fr=new ourframe();fr.show();}}

Fig. 2.9


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null, Exit }, this));

readonlyItem = new JCheckBoxMenuItem(Read-only);

ButtonGroup group = new ButtonGroup(); JRadioButtonMenuItem insertItem = new JRadioButtonMenuItem(Insert); insertItem.setSelected(true); JRadioButtonMenuItem overtypeItem = new JRadioButtonMenuItem(Overtype); group.add(insertItem); group.add(overtypeItem);

mbar.add(makeMenu(Edit, new Object[] { new JMenuItem(Cut, new ImageIcon(cut.gif)), new JMenuItem(Copy,

new ImageIcon(copy.gif)), new JMenuItem(Paste, new ImageIcon(paste.gif)), null, makeMenu(Options, new Object[] { readonlyItem, null, insertItem, overtypeItem }, this) }, this));

JMenu helpMenu = new JMenu(Help); helpMenu.setMnemonic(H);

mbar.add(makeMenu(helpMenu, new Object[] { new JMenuItem(Index, I), new JMenuItem(About, A) }, this));

popup = makePopupMenu( new Object[]

{ Cut, Copy, Paste }, this);

getContentPane().addMouseListener(new MouseAdapter()


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if (target instanceof ActionListener) r.addActionListener((ActionListener)target); return r; }

public static JPopupMenu makePopupMenu

(Object[] items, Object target) { JPopupMenu m = new JPopupMenu();

for (int i = 0; i < items.length; i++) { if (items[i] == null) m.addSeparator(); else m.add(makeMenuItem(items[i], target)); } return m; }

public static void main(String[] args) { Frame f = new MenuTest();

f.show(); } private JMenuItem saveItem; private JMenuItem saveAsItem; private JCheckBoxMenuItem readonlyItem; private JPopupMenu popup;}

Fig. 2.10


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Fig. 2.11

C:\jdk1.2\bin>java MenuTestOvertypeRead-onlyCopyNewOpenCutPaste

IndexAboutInsertExit


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}

void setupEventHandlers() {


fileExit.addActionListener(new MenuItemHandler());}

public static void main(String[] args) {

SwingTree app = new SwingTree();

}

public class WindowHandler extends WindowAdapter {

public void windowClosing(WindowEvent e) {

System.exit(0);

}

}

public class MenuItemHandler implements ActionListener {

public void actionPerformed(ActionEvent e) {

String cmd = e.getActionCommand();

if(cmd.equals(Exit)) System.exit(0);

}

}

class Renderer extends JLabel implements TreeCellRenderer {

public Component getTreeCellRendererComponent(JTree tree,

Object value, boolean selected, boolean expanded,

boolean leaf, int row, boolean hasFocus) {

setText(value.toString()+ ); return this;

}

}

}


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Fig. 2.12

Look and Feel


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Example 2.9:import java.awt.*;import java.awt.event.*;import javax.swing.*;

class PlafPanel extends JPanel implements ActionListener{ public PlafPanel() { metalButton = new JButton(Metal); motifButton = new JButton(Motif); windowsButton = new JButton(Windows);

add(metalButton);

add(motifButton); add(windowsButton);

metalButton.addActionListener(this); motifButton.addActionListener(this); windowsButton.addActionListener(this); }

public void actionPerformed(ActionEvent evt) { Object source = evt.getSource(); String plaf = ; if (source == metalButton) plaf = javax.swing.plaf.metal.MetalLookAndFeel; else if (source == motifButton)

plaf = com.sun.java.swing.plaf.motif.MotifLookAndFeel; else if (source == windowsButton) plaf =com.sun.java.swing.plaf.windows.WindowsLookAndFeel; try { UIManager.setLookAndFeel(plaf); SwingUtilities.updateComponentTreeUI(this);


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} catch(Exception e) {} }

private JButton metalButton; private JButton motifButton;

private JButton windowsButton;}class PlafFrame extends JFrame{ public PlafFrame() { setTitle(PlafTest); setSize(300, 200); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { System.exit(0); } } );

Container contentPane = getContentPane(); contentPane.add(new PlafPanel());

}}

public class PlafTest{ public static void main(String[] args) { JFrame frame = new PlafFrame(); frame.show(); }}

Fig. 2.13


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{


{

System.exit(0);

} });


con.add(new tPanel());

setVisible(true);

}

}

class tPanel extends JPanel{

Timer timerActivity,timerCountdown;

int TIMEOUT=40;

int countdownTicks=TIMEOUT;

JLabel countdownDisplay;

public tPanel()

{

setLayout(new BorderLayout());

requestFocus();

String s=Application will terminate +TIMEOUT+ seconds of

inactivity ;

add(new JLabel(s),North);

add(countdownDisplay=new

JLabel(Integer.toString(TIMEOUT)),South);

addKeyListener(new KeyAdapter(){

public void keyPressed(KeyEvent e)

{

timerActivity.restart();

countdownTicks=TIMEOUT;

updateDisplay();

}

});

addMouseListener(new MouseAdapter(){

public void mouseClicked(MouseEvent e)

{


countdownTicks=TIMEOUT;

updateDisplay();}

});

addMouseMotionListener(new MouseMotionAdapter(){

public void mouseMoved(MouseEvent e){



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Going Over It Again





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Session 3

Beans Fundamentals


Java Beans Basics

Beans Architecture

Bean Box

Creating a Bean

Bundled Beans


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Builder

Bridges

Bean Concepts

By adhering to specific naming conventions, known as design patterns, whennaming Bean features. Bean introspection relies on the API to discover Bean

features via design patterns.

By explicity providing property, method, and event information with a relatedBean Information class. A Bean information class implements the BeanInfo

interface.


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Bean Box

Property Sheet

Fig. 3.3


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Fig. 3.4

Using Bean Box

Fig. 3.5


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Fig. 3.6

Fig. 3.7


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Using Bound Properties

Fig. 3.9

Fig. 3.10


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Fig. 3.11

Creating a Bean

Create a bean source code as a java file in our JDKs bin directory and compile itusing javac.

Create a manifest file which will identify the .class file as a bean.

Create a jar file which will contain the .class file and a .mf file.

Copy the jar file into BDKs jars directory.

In command line run the beanbox usually we can get our bean in the Toolbox.

Example 3.1:

import java.awt.*;

import java.io.Serializable;import java.beans.*;public class mybean extends Canvasimplements Serializable{

public mybean()


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Fig. 3.13

Fig. 3.14

Other Bundled Beans


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JDBC SELECT

Fig. 3.16

The QuoteMonitor


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Beans Fundamentals

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Fig.. 3.17

Other beans

SummaryIn this session we have seen the basic things related to the Java Beans. Here

we have dealt about the BDK and its requirements. We have used some of the

bundled beans to get the practical idea about the beans. Also we have seen the

creation of our own beans and its display in the toolbox. Now we can create

our own bean and add it to the tool box.

Going Over It Again



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Session 4

Inside Beans


Introspection

Persistence in Beans

Java.Beans Package

BeanInfo Interface


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Inside Beans

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Fig. 4.2

Fig. 4.3


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This is an example of the use of the generatedMyApplet applet. Notice the Applet tag requires severalarchives, one per JAR used in building the Applet

Trouble instantiating applet MyApplet!!

Persistence


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Making Beans Serializable

Fig. 4.6


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Inside Beans

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private transient Date mytime;

Java.Beans Package

Methods Usage

instantiate() Creates an instance of a bean from the serialized

object.

isInstanceOf() Determines if a bean is of a specified class or

interface.

getInstanceOf() Returns an object that represents a particular view ofa

bean.

isDesignTime() Determines whether beans are running in an

application builder environment.

setDesignTime() Identifies the fact that beans are running in an

application builder environment.

isGuiAvailable() Determines whether a GUI is available for beans.

setGuiAvailable() Identifies the fact that a GUI is available for beans.


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package sunw.demo.juggler;import java.beans.*;

import java.awt.Image.*;

public class JugglerBeanInfo extends SimpleBeanInfo

{

public Image getIcon(int iconKind)

{

if (iconKind == BeanInfo.ICON_COLOR_16x16)

{

Image img;

img = loadImage(JugglerIcon.gif);

return img;

}return null;

}

}

Manifest-Version: 1.0

Name: JugglerBean.class

Java-Bean: True

Name: JugglerBeanInfo.class

Java-Bean: False

Name: JugglerIcon.gifJava-Bean: False


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Event Handling Classes

Other Interfaces

Aggregation

Summary

In this session we have seen the introspection concept related to the Java Beans. Alsowe have dealt with serialization in JavaBeans. We have used some of the classes in

the java.beans packages. In the middle of the session we have seen the BeanInfo

interface and its classes along with an example. At the end of the session we learnt

about various descriptors and its concepts.


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Inside Beans

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Going Over It Again





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Session 5

Servlet Programming


Java Servlets Basics

Servlets Classes

Developing & Running Servlets

HTML Form Handling

Life Cycle of Servlets


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In This Session...

Introduction to Server-Side Java

Servlets

The Other World

Why Servlets?

Supports for Servlets

Servlet Architecture

Developing a Servlet

Running a Servlet

Handling HTML Form

Servlet Life Cycle

Init and Destroy Methods

Service Method


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Servlet Programming

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Introduction to Server-Side Java

Servlets


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The Other World


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Servlet Programming

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Common Gateway Interface (CGI)

For CGI implementation, the most common platform independent language is

perl.

But it requires the server to start a new interpreter for every request.

CGI runs in a completely separate process from the web server. If a client submits

a request to a CGI program that terminates before responding to the web server,

the browser has no way of knowing what happened. It just sits there waiting for

a response until it times out. A web server creates a new process every time it receives a CGI request. This

result in the loss of response time, because the server must create and initialize a

new address space for every process.

Active Server Pages (ASP)

Server-side JavaScript

Server Extension APIs


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Why Servlets?

Efficient

Persistent

Portable

Robust


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Extensible

Flexible

Secure

Widespread Acceptance

Supports for Servlets

Servlet Engines


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Servers with built in Servlet Support

Product Vendor

Acme.Serve AcmeJavaSoftware

ApacheWebServer Apache

DominoGoWebServer Lotus

DynamoApplicationServer ATG

EnterpriseServer NetscapeEnterpriseServer KonaSoft

InternetConnectionServer IBM

ITP WebServer Tandem

JavaWebServer SunMicrosystems

Jetty MorBay

JigsawServer WorldWideWebConsortium

NetForge Novocode

ServletFactory EarlyMorningSoftware

SunWebServer SunMicrosystems

TengahApplicationServer WebLogic

VisualAgeWebRunnerToolkit IBM

WEASAL WebEasy

WebCore Paralogic

Website Professional OReilly

ZeusWebServer Zeus Technology

Third-Party Add-Ons with Servlet Support

Product VendorWAICoolRunner Gefion Software

Jrun Live Software

ServletExec NewAtlanta

Servlet CGI Development Kit Unicom

Web Sphere Application Server IBM


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Servlet Architecture

GenericServlet and HttpServlet

public abstract void service(ServletRequest req,

ServletResponse res) throws ServletException, IOException;

Server Service()

Request

Response

(Generic Servlet )

Fig. 5.1


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protected void service(HttpServletRequest req,

HttpServletResponse resp)throws ServletException, IOException;

Server

Service()

d o G e t ( )

Service()

d o P o s t ( )

GET

Request

Response

POST

Request

Response

HTTP Servlet

Fig. 5.2

Developing a Servlet


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Example 5.1:

import java.io.*;import javax.servlet.*;import javax.servlet.http.*;

public class hello extends HttpServlet{public void doGet(HttpServletRequest req,HttpServletResponse res) throws ServletException, IOException

{res.setContentType(text/html);PrintWriter out= res.getWriter();out.println();out.println( Hello Servlets!! );out.println();out.println( Hello Guys! Servlet Welcomes You!! );out.println();}}

Running a Servlet

Java Servlet Development Kit (JSDK). It contains the servlet API class fileswhich will support our servlet packages.

Any one of the Servlet engines which are listed in the previous sections.


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Write the servlet program and save it with .java extension.

Compile the code using javac like a Java program. (remember that the directorywhich contain our .java file should have the JSDK)

Then copy the .class file in to the servletsdirectory of our Apache server.

Now open the browser. Enter the URL of our servlets file. The syntax is htttp:///servlets/.

Fig. 5.3

Handling HTML Form


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Example 5.2:

// first.html

HTML & Servlets


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out.println(

);out.println(My Country is: +name2);out.println();}

}

Fig. 5.4

Fig. 5.5


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Servlet Life Cycle

Init and Destroy Methods

init()

When the server starts

When the servlet is first requested, just before the service() method is invoked.

At the request of the server administrator.

public void init(ServletConfig config) throws ServletException;


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destroy()

public void destroy();

Service Method

public void service(ServletRequest req, ServletResponse res)throws ServletException, IOException;

Example 5.3:

import javax.servlet.*;import javax.servlet.http.*;

import java.io.*;import java.util.*;

public class ex2 extends HttpServlet{ public void init(ServletConfig config) throws ServletException {


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// Always pass the ServletConfig object to the super class super.init(config);}

//Process the HTTP Get request public void doGet(HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException{ response.setContentType(text/html);

PrintWriter out = response.getWriter(); out.println(); out.println(BasicServlet); out.println();

// Prints the REQUEST_METHOD sent by the client out.println(Your request method was + request.getMethod() + \n); out.println(); out.close(); }//Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(text/html); PrintWriter out = response.getWriter(); out.println(); out.println(BasicServlet); out.println();// Prints the REQUEST_METHOD sent by the client

out.println(Your request method was + request.getMethod() + \n); out.println(); out.close(); }

//Get Servlet information

public String getServletInfo() { return BasicServlet Information; }}


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Fig. 5.6

Life Cycle of Servlet

Press Submit Button to invoke your method


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Fig. 5.7

SummaryIn this session we learnt about Java Servlets basics, usage of servlets, servlets

alternatives and the basic architecture of Java Servlets. Then experienced withwriting a simple servlet and running the servlet. We also learnt how the servlets are

performed behind the HTML code. At the end of the session we learnt about the life

cycle of the Java Servlets and its methods.

Going Over it Again



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I. State True or False



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Session 6

More on Servlets


Server & Client

Servlet Chaining

HTML Generation

Servlet in a Middle Tier


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In This Session...

The Server

The Client

The Request

Servlet Chaining

HTML Generation

Building HTML Packages

HTML Object

HTML Document

HTML Elements

HTML Form

Using HTML Package

Servlet- A Middle Tier


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More on Servlet

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The Server

public string ServletRequest.getServerName()public int ServletRequest.getServerPort()

public string ServletContext.getServerInfo()public object ServletContext.getAttribute()

String str = getServletContext().getServerInfo()

Example 6.1:

import java.io.*;import java.util.*;import javax.servlet.*;

public class ex1 extends GenericServlet{


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public void service(ServletRequest req, ServletResponse res)throws ServletException,IOException{res.setContentType(text/plain);PrintWriter out= res.getWriter();

out.println(Server Host Name: +req.getServerName());out.println(ServerPort: +req.getServerPort());out.println(Servlet Context: +getServletContext().getServerInfo());

}

}

Fig. 6.1

The Client


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public String ServletRequest.getRemoteAddr()public String ServletRequest.getRemostHost()

InetAddress add = InetAddress.getByName(req.getRemoteAddr())

public String HttpServletRequest.getRemoteUser()

The Request

public String ServletRequest.getParameter(String name)public String[] ServletRequest.getParameterVales(String name)


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Example 6.2:

import java.io.*;import java.util.*;import javax.servlet.*;import javax.servlet.http.*;public class ex2 extends HttpServlet{

public void doGet(HttpServletRequest req, HttpServletResponseres)throws ServletException,IOException{res.setContentType(text/plain);PrintWriter out= res.getWriter();

out.println(Query String...);out.println(req.getQueryString());out.println(The file \ + req.getPathInfo()+\);out.println(Is stored at \ + req.getPathTranslated()+\);}}

Fig. 6.2


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More on Servlet

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http://205.166.22.74/servlets/ex2?parameter1

Fig. 6.3

Note

When giving any URL there should not be a space. Also the ? symbolseparates the file name from the parameters. If we want to give more than one

parameter, we can pass a number of parameters concatenating with + symbol.

For example,

Servlet Chaining


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Server

Servlet1

Servlet2

Servlet3

Request

Response

Fig. 6.4

By using the servlets we can quickly change the appearance of a page or a groupof pages, or type of content.

We can take a kernal of content and display it in special formats.

It also support esoteric data types

They handle the content of the future, so we dont have to run our script every

time new content is added.

Example 6.3:

import java.io.*;

import java.util.*;import javax.servlet.*;import javax.servlet.http.*;

public class ex3 extends HttpServlet{


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public void doGet(HttpServletRequest req, HttpServletResponseres)throws ServletException,IOException

{String contentType=req.getContentType();

if(contentType==null)return;res.setContentType(contentType);PrintWriter out= res.getWriter();BufferedReader in= req.getReader();String line=null;

while((line= in.readLine())!=null){line=replace(line,, );line=replace(line,, );out.println(line);}

}

public void doPost(HttpServletRequest req, HttpServletResponseres)throws ServletException,IOException{doGet(req,res);}

private String replace(String ln, String old, String news){int id=0;while((id=ln.indexOf(old, id))>=0)

{ln=ln.substring(0,id)+ news + ln.substring(id+old.length());id+=news.length();}return ln;}}

HTML Generation


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Building HTML Packages

HTMLObject

Example 6.4:

package HTML;import java.util.Vector;public abstract class HTMLObject{protected Vector htmlObjects = null; // Static Alignment values public static final int LEFT = 0; public static final int CENTER = 1; public static final int RIGHT = 2; // Set the objects initial alignment to LEFT private int alignment = LEFT; // This abstract method forces all derived classes to


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// implement the toHTML() method. The toHTML() method // should return the HTML String necessary to // display this object in its current state. public abstract String toHTML(); // Constructor public HTMLObject() {

// Default size of HTMLObject vector htmlObjects = new Vector(5); } // Add a HTMLObject public void addObject( HTMLObject value) { if ( value != null ) { htmlObjects.addElement(value); } } // Remove a HTMLObject, if the element is removed // successfully, returns true public boolean removeObject( HTMLObject value) { if ( value != null ) {

return htmlObjects.removeElement(value); } return false; } // Set the objects Alignment public void setAlignment(int value) { if ( value >= LEFT && value


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private String backgroundColor = new String(); private String textColor = new String(); private String linkColor = new String(); private String vlink = new String(); private String alink = new String(); // Default Constructor

public HTMLDocument() { } // Constructor with title public HTMLDocument(String value) { title = value; } // Set the document Title public void setTitle(String value) { if ( value != null ) { title = value; } } // Get the document Title

public String getTitle() { return title; } // Set the document Background Image public void setBackgroundImage(String value) { if ( value != null ) { backgroundImage = value; } } // Get the document Background Image public String getBackgroundImage() { return backgroundImage; }

// Set the document Background Color public void setBackgroundColor( String value) { if ( value != null ) { backgroundColor = value; } } // Get the document Background Color public String getBackgroundColor() { return backgroundColor; } // Set the document Text Color public void setTextColor(String value) {

if ( value != null ) { textColor = value; } } // Get the document Text Color public String getTextColor() { return textColor;


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} // Set the document Link Color public void setLinkColor(String value) { if ( value != null ) { linkColor = value; }

} // Get the document Link Color public String getLinkColor() { return linkColor; } } // Return String containing the HTML formatted document public String toHTML() { String document = new String(\n); document = document.concat( + title + \n\n 0 ) { document = document.concat(BACKGROUND=\ +

backgroundImage + \ ); } String color = getBackgroundColor(); if ( color.length() > 0 ) { document = document.concat(BGCOLOR=\ + color + \ ); } String textColor = getTextColor(); if ( textColor.length() > 0 ) { document = document.concat(TEXT=\ + textColor + \ ); } if ( linkColor.length() > 0 ) {

document = document.concat(LINK=\ + linkColor + \ ); } if ( vlink.length() > 0 ) { document = document.concat(VLINK=\ + vlink + \ ); } if ( alink.length() > 0 ) { document = document.concat(ALINK=\ + alink + \ ); } document = document.concat(>\n); // Iterate through all objects in the htmlObjects Vector for ( int x = 0; x < htmlObjects.size(); x ++ ) { try {

document = document.concat( ((HTMLObject)htmlObjects.elementAt(x)).toHTML() + \n); } catch (ArrayIndexOutOfBoundsException ex) { // This will only log the error to stderr


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System.err.println(ex.getMessage()); } catch (Exception ex) { // This will only log the error to stderr System.err.println(ex.getMessage()); }

} // Then close the document document = document.concat(\n\n\n); return document; }}

HTML Elements

HTMLText

Example 6.6:

package HTML;public class HTMLText extends HTMLObject { private String text = new String(); private boolean bold = false;

private boolean italic = false; private boolean underline = false; private boolean center = false; // Default Contructor public HTMLText() { } // Constructor initialized with Text value public HTMLText(String value) { if ( value != null ) { text = value; } } // Set the text value

public void setText(String value) { if ( value != null ) { text = value; } } // Get the current text value public String getText() {


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return text; } // Set Text Bold to true/false public void setBold(boolean value) { bold = value; }

// Returns True if Bold is on public boolean isBold() { return bold; } // Set Text Italic to true/false public void setItalic( boolean value) { italic = value; } // Returns True if Italic is on public boolean isItalic() { return italic; } // Set Text Underline to true/false

public void setUnderline( boolean value) { underline = value; } // Returns True if Underline is on public boolean isUnderline() { return underline; } // Set Text Center to true/false public void setCenter( boolean value) { center = value; } // Returns True if Center is on public boolean isCenter() {

return center; } // Set Text Preformatted to true/false // Return String containing the HTML formatted Text public String toHTML() { String html = new String (text); if ( isBold() ) { html = ( + html + ); } if ( isItalic() ) { html = ( + html + ); } if ( isUnderline() ) {

html = ( + html + ); } if ( isCenter() ) { html = ( + html + ); } if ( isPreformatted() ) { html = ( + html + );


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} return html; }}

HTMLHeading

Example 6.7:

package HTML;public class HTMLHeading extends HTMLObject { private String text = new String(); private int heading; public static final int H1 = 1;

public static final int H2 = 2; public static final int H3 = 3; public static final int H4 = 4; public static final int H5 = 5; public static final int H6 = 6; // Constructor that initializes Heading Level to H1 public HTMLHeading() { heading = H1; } // Constructor that sets the initial Heading Text and Level public HTMLHeading(String txt, int head) { if ( txt != null ) { text = txt; } if ( head >= H1 && head = H1 && value


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// Get Heading Level public int getHeadingLevel() { return heading; } // Return String containing the HTML formatted Heading public String toHTML() {

String html = new String( + text + );

return html; }}

HTMLLineBreak

Example 6.8:

package HTML;public class HTMLLineBreak extends HTMLObject{ // Default Constructor public HTMLLineBreak() { } // Return String containing the HTML formatted Line Break public String toHTML() { return new String(
); }}

HTMLInput


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Example 6.9:

package HTML;

public class HTMLInput extends HTMLObject { protected String type = new String(); protected String name = new String(); protected String input_value = new String(); protected String attributes = new String(); // Default Constructor public HTMLInput() { } // Set the Input Type protected void setType(String value) { if ( value != null ) { type = value; }

} // Get the Input Type public String getType() { return type; } // Set the Input Name public void setName(String value) { if ( value != null ) { name = value; } } // Get the Input Name public String getName() {

return name; } // Set the value of the Input Object public void setValue(String value) { if ( value != null ) { input_value = value; } } // Get the value of the Input Object public String getValue() { return input_value; } // Set the additional attributes string // This will be used to specialize an input type protected void setAttributes(String value) { if ( value != null ) { attributes = value; } } // Get the additional attributes string


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public String getAttributes() { return attributes; } // Return String containing the HTML formatted Input public String toHTML() { String html = new String( 0 ) { html = html.concat( VALUE=\ + input_value + \); } // If there is any additional attributes if ( attributes != null ) { html = html.concat(attributes); } // Ending Character html = html.concat(>); return html; }

}

HTMLInput Object

Example 6.10:

package HTML;

public class HTMLTextInput extends HTMLInput { private int size = -1; private int maxlength = -1; // Default Constructor public HTMLTextInput() { // Set the Input Type setType(TEXT); } // Set the Input Size public void setSize(int value) { if ( value > -1 ) { size = value; }

} // Get the Input Size public int getSize() { return size; } // Set the Maximum Length public void setMaxLength(int value) {


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if ( value > -1 ) { maxlength = value; } } // Get the Maximum Length public int getMaxLength() {

return maxlength; } // Return String containing the HTML formatted Text Input public String toHTML() { String html = new String(); if ( size > -1 ) { html = html.concat( SIZE= + size); } if ( maxlength > -1 ) { html = html.concat( MAXLENGTH= + maxlength); } setAttributes(html); return super.toHTML();

}}

HTMLForm

Example 6.11:

package HTML;import java.util.*;public class HTMLForm extends HTMLObject { private String action = new String(); private boolean post_method = false; private String enctype = new String (text/html); // Default Constructor public HTMLForm() { } // Set the action public void setAction( String value) { if ( value != null ) { action = value;

} } // Get the action public String getAction() { return action; } // Set the POST method to true/false


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public void setPostMethod( boolean value) {

post_method = value;

}

// return true if POST, otherwise false

public boolean isPostMethod() {

return post_method; }

// Set the ENCTYPE, ie. text/html

public void setEnctype( String value) {

if ( value != null ) {

enctype = value;

}

}

// Get the ENCTYPE

public String getEnctype() {

return enctype;

}

// Return String containing the HTML formatted Form public String toHTML() {

String html = new String(\n); // adding HTMLInputs

for ( int x = 0; x < htmlObjects.size(); x++ ) {

try {

html = html.concat(

((HTMLObject)htmlObjects.elementAt(x)).toHTML() +

\n);

}

catch (Exception ex) {

// Print exception to stderr

System.err.println(ex.getMessage());

}

} html = html.concat(\n);

return html;

}

}


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Using HTML Package

Example 6.12:

import javax.servlet.*;import javax.servlet.http.*;import java.io.*;import java.util.*;import HTML.*;public class expack extends HttpServlet {

public void init(ServletConfig config) throws ServletException{ super.init(config); } //Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType(text/html); PrintWriter out = response.getWriter(); HTMLDocument document = new HTMLDocument(New Customer Account); // Create the New Customer Account Form HTMLForm form = new HTMLForm(); form.setAction(/servlet/NewCustomerServlet); form.setPostMethod(true); // Add the Heading HTMLHeading heading = new HTMLHeading(Customer Account, HTMLHeading.H2); heading.setAlignment(HTMLObject.CENTER); form.addObject(heading); // Add the Name form.addObject(new HTMLText(Name : )); HTMLTextInput textinput = new HTMLTextInput(); textinput.setName(name); textinput.setSize(30); form.addObject(textinput);

form.addObject(new HTMLLineBreak());

// Add the Email form.addObject(new HTMLText(Email Address : ));

textinput = new HTMLTextInput();

textinput.setName(email);

textinput.setSize(30);


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form.addObject(textinput);


// Add the Billing Address

form.addObject(new HTMLHeading(Billing Address,

HTMLHeading.H4));

form.addObject(new HTMLText(Street : )); textinput = new HTMLTextInput();

textinput.setName(street);




// Add the City, State, Zip

// City

form.addObject(new HTMLText(City ));


textinput.setName(city);

textinput.setSize(30); form.addObject(textinput);

// State

form.addObject(new HTMLText(State ));


textinput.setName(state);


textinput.setMaxLength(2);


// Zip

form.addObject(new HTMLText(Zip )); textinput = new HTMLTextInput();

textinput.setName(zip);


textinput.setMaxLength(5);



document.addObject(form);

// document string sent back in response

out.println(document.toHTML());

out.close();

}

//Get Servlet information

public String getServletInfo() {

return NewCustomerServlet Information;

}

}


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Fig. 6.5

Servlet A Middle Tier


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Example 6.13:

import java.io.*;import java.sql.*;import javax.servlet.*;import javax.servlet.http.*;

public class db extends HttpServlet{

public void doPost(HttpServletRequest req, HttpServletResponseres)throws ServletException, IOException{res.setContentType(text/html);PrintWriter out=res.getWriter();

Connection con=null;

try{Class.forName(sun.jdbc.odbc.JdbcOdbcDriver);

con=DriverManager.getConnection(jdbc:odbc:srt,scott,tiger);

con.setAutoCommit(false);

Statement s=con.createStatement();s.executeUpdate(update emp set eno=40 where ename=John);

con.commit();out.println(Update Successful!);}catch(Exception e){

try{

con.rollback();}

catch(SQLException ie){}out.println(Could not Upadate!);}

finally{

try{if (con!=null) con.close();}catch(SQLException ing){}}

}}


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SummaryIn this session we covered a lot of information related to servlets. We looked at

how the server and the client works in relation to the servlets. Also we looked at

servlet chaining. We created an HTML package that encapsulates basic HTML.

By now we should have an in-depth understanding of how to use the HTMLpackage we created. At the end of this session we learnt about the usage of the

servlet in database programming.

Going Over it Again




5. What is the use of the getAttribute() method?


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Session 7

Java Stored Procedures


Overview of Java Stored Procedures

Usage of JDBC and SQLJ

Build an ApplicationSub Programs in SQLJ

Relationship of SQLJ to Embedded SQL


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In This Session...

Java Stored Procedures - An Overview

Goal for Designing SQLJ

SQLJ Variables

JDBC OCI Driver

When to Use JDBC and When to Use SQLJ?

SQL appears in Java Statements

Building an Application

Sub Programs in SQLJ

Calling Stored Procedures

Calling Stored Functions

Relationship of SQLJ to Embedded SQL

Advantages of SQLJ over JDBC


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Java Stored Procedures An Overview

Connection conn = new OracleDriver().defaultConnection();

C:\sqlj\demo>Loadjava


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Two Components of SQLJ

Translator

Runtime

Translator

Runtime


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Java Source Code with Embedded

Java Source Cod e with calls to JD BC

Java Byte Cod e with calls to JDBC

JDBC Dr iver

Databases

SQLJ Translator

Java Compiler

SQLJ Source

Java Source

Java Executable

Java Executable

Fig. 7.1

Requirements for SQLJ

JDBC driver implementing the standard java.sql JDBC interfaces from SunMicrosystems

Oracle SQLJ works with any standards-compliant JDBC driver.

Database system that is accessible using your JDBC driver

Class files for the SQLJ translator, SQLJ profile customizer, and SQLJ runtime


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JDK1.1.7 Version of Java to Execute the SQLJ Converted Java Programs, OracleJDBC drivers for version 8.1.5 do not support the JDK 1.2.

Fig. 7.2

Goal for Desiging SQLJ


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Standard Embedded SQL

Brevity

Type Checking

Schema Checking

Autonomous Development

Location Transparency


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Portability

Generality

Optimization of SQL

Database Stored Programs

Component Software

Consistency with Java


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Java has automatic storage management (garbage collection) that simplifies themanagement of storage for data retrieved from databases.

All Java types representing composite data, and data of varying sizes, have adistinguished value null, which can be used to represent the SQL NULL state,

giving Java programs an alternative to NULL indicators, which are a fixture ofother host languages.

Java is designed to support programs that are automatically heterogeneouslyportable (also called super-portable or simply downloadable). That, along

with Javas type system of classes and interfaces, enables component software.

In particular, a SQLJ translator, written in Java, can call components that are

specialized by database vendors, in order to leverage the existing schema-

checking and type-checking capabilities of databases, and to generate code

optimized for particular databases.

Java is designed for binary portability in heterogeneous networks, which

promises to enable binary portability for database applications that use staticSQL.

Availability of Development Tools

Tracing

Debugging

Specification of breakpoints

Automatic code formatting

Code analysis and highlighting

Automatic regeneration of byte codes

Usage Scenarios

Low Level: This is Embedded SQL as 3GL developers know it today. This levelhas a loose integration with the type system of the host language. Programming

tools, such as visual or syntax-directed tools, are likely to generate Java code

containing static SQL at this level, because the generated code is correct by

construction as generated from a tools model of the relationships among the

data.


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Middle Level: Human programmers use this level when they write SQLJ codedirectly. Tight, concise integration of the SQL and Java constructs and type

systems help programmers avoid and detect errors in their programs.

High Level: At this level, programmers use graphical tools to constrain and

compose their programs. Those tools will generate Java programs containingstatic SQL. Those generated programs may contain low-level Embedded SQL

because they are correct by construction.

SQLJ Variables

SQLJ Data Type Java Data Type

Char String

Varchar String

LongVarchar String

Numeric java.math.BigDecimal

Decimal java.math.BigDecimal

Bit boolean

TinyInt byte

SmallInt Short

Integer int

BigInt longReal float

Float double

Double double

Binary byte[ ]

VarBinary byte[ ]

LongVarBinary byte[ ]

Date java.sql.Date

Time java.sql.Time

Timestamp java.sql.Timestamp


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class First{ public static void main(String args[]) { int Value; Var=100;

System.out.println(Content of Variable Value is +Value); }}

The keyword class is used to define the class with the name First, within the classwe can declare the methods(Procedures & Functions).

main() program is declared as public to make it visible to the entire class.

static declaration is used because it cannot be instantiated

void indicates that main does not return the value.

Variable args is declared so that the main function can take command linearguments. This array holds string values.

NoteAll the variables and syntaxes are case sensitive, which means class is not equivalent

to Class and VALUE is not equivalent to Value.

JDBC OCI Driver


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import java.sql.SQLException;import java.sql.DriverManager;import java.sql.Driver;import java.sql.Connection;import sqlj.runtime.ref.DefaultContext ;

public class ConnectionManager {

static public String DRIVER = null ;static public String DBURL = null ;static public String UID = null ;static public String PWD = null ;static {

DRIVER = oracle.jdbc.driver.OracleDriver ; DBURL = jdbc:oracle:oci8:@Database_Name ; UID = ritchie ; PWD = ritchie ; }

static public Connection newConnection() { Connection conn = null;

if (UID== null || PWD==null || DBURL==null || DRIVER==null) {

System.err.println ( Please edit the ConnectionManager.java file to assign + non-null values to the static string variables + DBURL, DRIVER, UID, and PWD. Then recompile and tryagain. ) ; System.exit(1) ; }

try { Driver d = (Driver)(Class.forName( DRIVER ).newInstance()); DriverManager.registerDriver(d); } catch (Exception e) {

System.err.println( Could not load driver: + DRIVER ) ; System.err.println(e) ; System.exit(1) ; } try {

conn = DriverManager.getConnection (DBURL, UID, PWD);

} catch (SQLException exception) {


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System.out.println(Error: could not get a connection);

System.err.println(exception) ;

System.exit(1);

}

return conn;

}

static public DefaultContext initContext()

{

DefaultContext ctx = DefaultContext.getDefaultContext();

if (ctx == null) {

try {

ctx = new DefaultContext(newConnection());

} catch (SQLException e) {

System.out.println(Error: could not get a default context);

System.err.println(e) ;

System.exit(1);

}

DefaultContext.setDefaultContext(ctx);

}

return ctx;

}

}

C:\>javac ConnectionManager.java


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When to Use JDBC and When to Use SQLJ ?

To check program for errors at translation-time rather than at run-time.

To write an application that can deploy to another database. SQLJ can customizethe static SQL

For database at deployment-time.

While Working with a database that contains compiled SQL.

To use dynamic SQL.

To have a SQLJ layer during deployment or development.

Three Kinds of SQLJ clauses

#sql iterator iterator_classname (type declarations);

#sql public iterator EmpIterator (String job, double Comm);


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Example for positional Iterator

#sql public iterator EmpIterator (String, double);

#sql context context_classname;

Example

#sql context TestContext;

Executable clauses

Statementclause == #sql [connection] [statement]

#sql {Select EmpNo, Ename, Sal into :Eno, :En, :Salary From Emp};

#sql [connection] var ={SQL statement or Function };

Iterator java_var#sql x={ Select Ename, job, sal from Emp where Sal > 1000};


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FETCH iterator_name into :variable1, :variable2,:variable3..........(: should used before the variable)Where variable1, variable2, variable3..........

SQL appears in Java statements

SQL procedure statement

SQL dynamic statement


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SQL connection statement

Host variable definition


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SQL92 character sets

Embedded exception declaration

EXEC SQL WHENEVER exception-conditionGOTOprogram-label;EXEC SQL WHENEVER exception-conditionCONTINUE;


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try block-that-may-throw-exception-e catch (Exception e) block-that-handles-exception-e

SQL diagnostics statement

Declare cursor

Input parameters to SQL statements

Extracting column-values from result-sets

EXEC SQL FETCH cursor1 INTO :var1,:var2,:var3;


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OPEN cursor

EXEC SQL OPEN cursor1;

Build an Application


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import java.lang.*;import java.sql.SQLException;public class Server{public static void main(String args[]){try{String msg=Java Class Available in User_Objects Schema Table;#sql { Call Dbms_Output.put_line(:msg) };}catch(SQLException e) { System.out.println(e.getMessage()); }

}

Fig. 7.3


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Fig. 7.4

import java.sql.*;import java.sql.SQLException;

public class Objects{public static void main(String args[]){String msg=null;try{#sql { Create table Dept(DeptNo Number(2) Constraint Dept_prim Primary key,Dname varchar2(20) Unique,

Loc Varchar2(20)) };msg=Dept table is Created;#sql { Call DBMS_OUTPUT.PUT_LINE ( :msg ) };#sql { Create table Emp (EmpNo Number(4) Constraint Emp_prim Primary key,Ename varchar2(20) Unique,Sal Number(10,2),Comm Number(10,2),Mgr Number(4),Job Varchar2(20),HireDate date,

DeptNo number(2) Not null Constraint dept_Emp referencesDept(DeptNo)) };msg=Emp table is Created;#sql { Call Dbms_Output.put_line (:msg) };


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#sql { Create table SalGrade ( Grade Number(2), LoSal Number(10,2), HiSal Number(10,2) ) };

msg=SalGrade table is Created;#sql { Call Dbms_Output.put_line (:msg) };

#sql { Create table Bonus ( Ename Varchar2(20) Unique references Emp(Ename), Job Varchar2(20), Sal Number(10,2), Comm Number(10,2)

) };msg=Bonus table is Created;#sql { Call Dbms_Output.put_line (:msg) };}catch(SQLException e) { System.out.println(Error due to + e);

}}}

Fig. 7.5


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Fig. 7.5

Create Table Command

import java.sql.*;public class SQLTable

{ public static void main(String args[]) { try { ConnectionManager.initContext(); SQLTable C=new SQLTable(); C.Create(); } catch(SQLException e) { System.out.println (Error in your program); System.err.println(Error Description is + e); } }void Create() throws SQLException{ #sql { CREATE TABLE DEPT


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( DeptNo Number(3) Constraint Dept_prim Primary Key, Dname Varchar2(20) Not Null, Loc Varchar2(20) ) };

System.out.println(Table Created);}}

Open DOS prompt from start->Run->Command and goto the specified directoryC:\Sqlj\Demo.

Compile the sqlj program using sqljc SQLTable.sqlj

Once the program is compiled successfully, file with the same name but with.java (SQLTable.java) extension will be created.

Compile the .java file using java compiler javac SQLTable.java Once the program is compiled a file with the same name .class(SQLTable.class)

extension will be created and this is the executable file for SQLJ programs.

Execute the file using java SQLTable command.

Fig. 7.5


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Alter Table Command

import java.sql.*;public class SQLAlterTable{ public static void main(String args[]) { try { ConnectionManager.initContext(); SQLAlterTable C=new SQLAlterTable();

C.Alter(); } catch(SQLException e) { System.out.println (Error in your program); System.err.println(Error Description is + e); } }void Alter() throws SQLException{ #sql { ALTER TABLE DEPT

Modify Loc Varchar2(30) }; System.out.println(Table Dept Altered);}}


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C:\sqlj\demo>sqljc SQLAlterTable.sqlj

C:\sqlj\demo>javac SQLAlterTable.java

C:\sqlj\demo>java SQLAlterTableTable Dept altered

C:\sqlj\demo>

Rename Command

import java.sql.*;public class SQLRenameTable{ public static void main(String args[]) { try { ConnectionManager.initContext(); SQLRenameTable C=new SQLRenameTable(); C.Rename(); } catch(SQLException e) { System.out.println (Error in your program); System.err.println(Error Description is + e); } }void Rename() throws SQLException{

#sql { Rename Dept To Department };System.out.println(Table Dept is Renamed to Department);}}


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C:\sqlj\demo>sqljc SQLRenameTable.sqlj

C:\sqlj\demo>javac SQLRenameTable.java

C:\sqlj\demo>java SQLRenameTableTable Dept is Renamed to Department

C:\sqlj\demo>

Drop Table Command

import java.sql.*;

public class SQLDropTable{ public static void main(String args[]) { try { ConnectionManager.initContext();


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SQLDropTable C=new SQLDropTable(); C.Drop(); } catch(SQLException e) { System.out.println (Error in your program);

System.err.println(Error Description is + e); } }void Drop() throws SQLException{ #sql { DROP TABLE DEPT };System.out.println(Table Dept Dropped);}}

C:\sqlj\demo>sqljc SQLDropTable.sqlj

C:\sqlj\demo>javac SQLDropTable.java

C:\sqlj\demo>java SQLDropTable

Table Dept Dropped

C:\sqlj\demo>The table is now dropped.


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Sub Programs in SQLJ

connect internal;

create or replace package sqljutl as function has_default(oid number,

proc char, seq number, ovr number) return number;end sqljutl;/create or replace package body sqljutl is function has_default(oid number, proc char, seq number, ovr number) return number is def number; begin if proc IS NULL

then select DEFAULT# INTO def FROM ARGUMENT$ WHERE PROCEDURE$ IS NULL AND OBJ# = oid AND SEQUENCE# = seq AND OVERLOAD# = ovr; else select DEFAULT# INTO def FROM ARGUMENT$ WHERE PROCEDURE$ = proc AND OBJ# = oid AND SEQUENCE# = seq AND OVERLOAD# = ovr; end if;

if def IS NULL then return 0; else return 1; end if; end has_default;end sqljutl;/

grant execute on sqljutl to public ;


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Calling Stored Procedures

#sql { CALL Procedure_Name() };

Create or Replace procedure SalaryIncrement(Emp_No

Emp.Empno%type Default 7788,Salary Emp.Sal%type) as

Emp_sal Emp.Sal%type;

NoSalary Exception;

Tot_Sal Emp.Sal%type;

Begin

Select Sal into Emp_sal from emp where Empno=Emp_no;

if Emp_sal is Null then

Raise NoSalary;

else

Update Emp set sal =Sal+Salary where Empno=Emp_no;

Tot_sal:=Emp_sal + Salary;

Dbms_output.put_line(Salary updated from || Emp_sal || to

|| Tot_sal || for employee number || Emp_No);

end if;

Exception

when NoSalary then

Dbms_output.put_line(Salary does not exists for employee ||

Emp_No);

When No_Data_found then

Dbms_output.put_line(No Employee exists with the Number ||

Emp_No);

End;

Procedure created.


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import java.sql.*;public class ProcedureCall{

public static void main(String args[]) { try { ConnectionManager.initContext(); ProcedureCall P=new ProcedureCall(); P.Proc(); } catch(SQLException e) { System.out.println(Error in program!); System.out.println(Due to + e); } }

void Proc() throws SQLException { #sql { CALL SalaryIncrement(7788,2000) }; System.out.println(Salary is Increment for Employee 7788 by 2000"); }}

C:\sqlj\demo>sqljc ProcedureCall.sqlj

C:\sqlj\demo>javac ProcedureCall.java


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C:\sqlj\demo>java ProcedureCall

C:\sqlj\demo>

Calling Stored Functions

#sql res = { VALUES(Function_Name()) };

Create

Documents

Advanced Java Book