Teknologi 3D pada Halaman WEB: September 2025

Senin, 29 September 2025

JAVA Roadmap

The Java Roadmap You Must Know

1. Linux 2. Git 3. IDE - IntelliJ - Eclipse - VSCode 4. Core - Classes/Objects - OOP - Arrays - Classes - Packages - Polymorphism - Variables - Strings - Loops - Inheritances - Interfaces - Files - I/O Streams 5. Collections - Arrays - Lists - Maps - Stacks - Queues - Optionals 6. Advanced - Dependency Injection - Design Patterns - How JVM Works - Multi-Threading - Generics 7. Exception Handling - Checked Exceptions - Unchecked Exceptions 8. Streams & Functional Programming 9. Testing - Unit Testing - Integration Testing - Debugging Skills - Contract Testing - Mocking - Assertion Libraries 10. Databases - Database Design - Queries - Indexes - Joins - Functions - Schema Migration Tool (Flyway, Liquibase) - Relational Database - JDBC - NoSQL 11. Clean Code - SOLID Principles - N-Tier Architecture - Immutability 12. Logging 13. Multi-Threading 14. Build Tools - Maven - Gradle - Bazel 15. HTTP - Rest API - GraphSQL - How HTTP Works - API Design 16. Frameworks - Spring Boot - Play - Quarkus

Selasa, 16 September 2025

JAVA - Calculator

package calculator;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.Container;

import java.awt.FlowLayout;

import java.awt.Font;

import java.awt.GridLayout;

import java.awt.Window;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.KeyEvent;

import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import javax.swing.JButton;

import javax.swing.JDialog;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JMenu;

import javax.swing.JMenuBar;

import javax.swing.JMenuItem;

import javax.swing.JPanel;

import javax.swing.JTextArea;

import javax.swing.KeyStroke;

public class Calculator extends JFrame implements ActionListener{

// Variables

final int MAX_INPUT_LENGTH = 20;

final int INPUT_MODE = 0;

final int RESULT_MODE = 1;

final int ERROR_MODE = 2;

int displayMode;

boolean clearOnNextDigit, percent;

double lastNumber;

String lastOperator;

private JMenu jmenuFile, jmenuHelp;

private JMenuItem jmenuitemExit, jmenuitemAbout;

private JLabel jlbOutput;

private JButton jbnButtons[];

private JPanel jplMaster, jplBackSpace, jplControl;

* Font(String name, int style, int size)

Creates a new Font from the specified name, style and point size.

Font f12 = new Font("Times New Roman", 0, 12);

Font f121 = new Font("Times New Roman", 1, 12);

// Constructor

public Calculator()

{

/* Set Up the JMenuBar.

* Have Provided All JMenu's with Mnemonics

* Have Provided some JMenuItem components with Keyboard Accelerators

jmenuFile = new JMenu("File");

jmenuFile.setFont(f121);

jmenuFile.setMnemonic(KeyEvent.VK_F);

jmenuitemExit = new JMenuItem("Exit");

jmenuitemExit.setFont(f12);

jmenuitemExit.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_X,

ActionEvent.CTRL_MASK));

jmenuFile.add(jmenuitemExit);

jmenuHelp = new JMenu("Help");

jmenuHelp.setFont(f121);

jmenuHelp.setMnemonic(KeyEvent.VK_H);

jmenuitemAbout = new JMenuItem("About Calculator");

jmenuitemAbout.setFont(f12);

jmenuHelp.add(jmenuitemAbout);

JMenuBar mb = new JMenuBar();

mb.add(jmenuFile);

mb.add(jmenuHelp);

setJMenuBar(mb);

//Set frame layout manager

setBackground(Color.gray);

jplMaster = new JPanel();

jlbOutput = new JLabel("0");

jlbOutput.setHorizontalTextPosition(JLabel.RIGHT);

jlbOutput.setBackground(Color.WHITE);

jlbOutput.setOpaque(true);

// Add components to frame

getContentPane().add(jlbOutput, BorderLayout.NORTH);

jbnButtons = new JButton[23];

// GridLayout(int rows, int cols, int hgap, int vgap)

JPanel jplButtons = new JPanel(); // container for Jbuttons

// Create numeric Jbuttons

for (int i=0; i<=9; i++)

{

// set each Jbutton label to the value of index

jbnButtons[i] = new JButton(String.valueOf(i));

}

// Create operator Jbuttons

jbnButtons[10] = new JButton("+/-");

jbnButtons[11] = new JButton(".");

jbnButtons[12] = new JButton("=");

jbnButtons[13] = new JButton("/");

jbnButtons[14] = new JButton("*");

jbnButtons[15] = new JButton("-");

jbnButtons[16] = new JButton("+");

jbnButtons[17] = new JButton("sqrt");

jbnButtons[18] = new JButton("1/x");

jbnButtons[19] = new JButton("%");

jplBackSpace = new JPanel();

jplBackSpace.setLayout(new GridLayout(1, 1, 2, 2));

jbnButtons[20] = new JButton("Backspace");

jplBackSpace.add(jbnButtons[20]);

jplControl = new JPanel();

jplControl.setLayout(new GridLayout(1, 2, 2 ,2));

jbnButtons[21] = new JButton(" CE ");

jbnButtons[22] = new JButton("C");

jplControl.add(jbnButtons[21]);

jplControl.add(jbnButtons[22]);

// Setting all Numbered JButton's to Blue. The rest to Red

for (int i=0; i<jbnButtons.length; i++) {

jbnButtons[i].setFont(f12);

if (i<10)

jbnButtons[i].setForeground(Color.blue);

else

jbnButtons[i].setForeground(Color.red);

}

// Set panel layout manager for a 4 by 5 grid

jplButtons.setLayout(new GridLayout(4, 5, 2, 2));

//Add buttons to keypad panel starting at top left

// First row

for(int i=7; i<=9; i++) {

jplButtons.add(jbnButtons[i]);

}

// add button / and sqrt

jplButtons.add(jbnButtons[13]);

jplButtons.add(jbnButtons[17]);

// Second row

for(int i=4; i<=6; i++)

{

jplButtons.add(jbnButtons[i]);

}

// add button * and x^2

jplButtons.add(jbnButtons[14]);

jplButtons.add(jbnButtons[18]);

// Third row

for( int i=1; i<=3; i++)

{

jplButtons.add(jbnButtons[i]);

}

//adds button - and %

jplButtons.add(jbnButtons[15]);

jplButtons.add(jbnButtons[19]);

//Fourth Row

// add 0, +/-, ., +, and =

jplButtons.add(jbnButtons[0]);

jplButtons.add(jbnButtons[10]);

jplButtons.add(jbnButtons[11]);

jplButtons.add(jbnButtons[16]);

jplButtons.add(jbnButtons[12]);

jplMaster.setLayout(new BorderLayout());

jplMaster.add(jplBackSpace, BorderLayout.WEST);

jplMaster.add(jplControl, BorderLayout.EAST);

jplMaster.add(jplButtons, BorderLayout.SOUTH);

// Add components to frame

getContentPane().add(jplMaster, BorderLayout.SOUTH);

requestFocus();

//activate ActionListener

for (int i=0; i<jbnButtons.length; i++){

jbnButtons[i].addActionListener(this);

}

jmenuitemAbout.addActionListener(this);

jmenuitemExit.addActionListener(this);

clearAll();

//add WindowListener for closing frame and ending program

addWindowListener(new WindowAdapter() {

public void windowClosed(WindowEvent e)

{

System.exit(0);

}

);

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

} //End of Contructor Calculator

// Perform action

public void actionPerformed(ActionEvent e){

double result = 0;

if(e.getSource() == jmenuitemAbout){

JDialog dlgAbout = new CustomABOUTDialog(this, "About Java Swing Calculator", true);

dlgAbout.setVisible(true);

}else if(e.getSource() == jmenuitemExit){

System.exit(0);

}

// Search for the button pressed until end of array or key found

for (int i=0; i<jbnButtons.length; i++)

{

if(e.getSource() == jbnButtons[i])

{

switch(i)

{

case 0:

addDigitToDisplay(i);

break;

case 1:

addDigitToDisplay(i);

break;

case 2:

addDigitToDisplay(i);

break;

case 3:

addDigitToDisplay(i);

break;

case 4:

addDigitToDisplay(i);

break;

case 5:

addDigitToDisplay(i);

break;

case 6:

addDigitToDisplay(i);

break;

case 7:

addDigitToDisplay(i);

break;

case 8:

addDigitToDisplay(i);

break;

case 9:

addDigitToDisplay(i);

break;

case 10: // +/-

processSignChange();

break;

case 11: // decimal point

addDecimalPoint();

break;

case 12: // =

processEquals();

break;

case 13: // divide

processOperator("/");

break;

case 14: // *

processOperator("*");

break;

case 15: // -

processOperator("-");

break;

case 16: // +

processOperator("+");

break;

case 17: // sqrt

if (displayMode != ERROR_MODE)

{

try

{

if (getDisplayString().indexOf("-") == 0)

displayError("Invalid input for function!");

result = Math.sqrt(getNumberInDisplay());

displayResult(result);

}

catch(Exception ex)

{

displayError("Invalid input for function!");

displayMode = ERROR_MODE;

}

break;

case 18: // 1/x

if (displayMode != ERROR_MODE){

try

{

if (getNumberInDisplay() == 0)

displayError("Cannot divide by zero!");

result = 1 / getNumberInDisplay();

displayResult(result);

}

catch(Exception ex) {

displayError("Cannot divide by zero!");

displayMode = ERROR_MODE;

}

break;

case 19: // %

if (displayMode != ERROR_MODE){

try {

result = getNumberInDisplay() / 100;

displayResult(result);

}

catch(Exception ex) {

displayError("Invalid input for function!");

displayMode = ERROR_MODE;

}

break;

case 20: // backspace

if (displayMode != ERROR_MODE){

setDisplayString(getDisplayString().substring(0,

getDisplayString().length() - 1));

if (getDisplayString().length() < 1)

setDisplayString("0");

}

break;

case 21: // CE

clearExisting();

break;

case 22: // C

clearAll();

break;

}

void setDisplayString(String s){

jlbOutput.setText(s);

}

String getDisplayString (){

return jlbOutput.getText();

}

void addDigitToDisplay(int digit){

if (clearOnNextDigit)

setDisplayString("");

String inputString = getDisplayString();

if (inputString.indexOf("0") == 0){

inputString = inputString.substring(1);

}

if ((!inputString.equals("0") || digit > 0) && inputString.length() < MAX_INPUT_LENGTH){

setDisplayString(inputString + digit);

}

displayMode = INPUT_MODE;

clearOnNextDigit = false;

}

void addDecimalPoint(){

displayMode = INPUT_MODE;

if (clearOnNextDigit)

setDisplayString("");

String inputString = getDisplayString();

// If the input string already contains a decimal point, don't

// do anything to it.

if (inputString.indexOf(".") < 0)

setDisplayString(new String(inputString + "."));

}

void processSignChange(){

if (displayMode == INPUT_MODE)

{

String input = getDisplayString();

if (input.length() > 0 && !input.equals("0"))

{

if (input.indexOf("-") == 0)

setDisplayString(input.substring(1));

else

setDisplayString("-" + input);

}

else if (displayMode == RESULT_MODE)

{

double numberInDisplay = getNumberInDisplay();

if (numberInDisplay != 0)

displayResult(-numberInDisplay);

}

void clearAll() {

setDisplayString("0");

lastOperator = "0";

lastNumber = 0;

displayMode = INPUT_MODE;

clearOnNextDigit = true;

}

void clearExisting(){

setDisplayString("0");

clearOnNextDigit = true;

displayMode = INPUT_MODE;

}

double getNumberInDisplay() {

String input = jlbOutput.getText();

return Double.parseDouble(input);

}

void processOperator(String op) {

if (displayMode != ERROR_MODE)

{

double numberInDisplay = getNumberInDisplay();

if (!lastOperator.equals("0"))

{

try

{

double result = processLastOperator();

displayResult(result);

lastNumber = result;

}

catch (DivideByZeroException e)

{

}

else

{

lastNumber = numberInDisplay;

}

clearOnNextDigit = true;

lastOperator = op;

}

void processEquals(){

double result = 0;

if (displayMode != ERROR_MODE){

try

{

result = processLastOperator();

displayResult(result);

}

catch (DivideByZeroException e) {

displayError("Cannot divide by zero!");

}

lastOperator = "0";

}

double processLastOperator() throws DivideByZeroException {

double result = 0;

double numberInDisplay = getNumberInDisplay();

if (lastOperator.equals("/"))

{

if (numberInDisplay == 0)

throw (new DivideByZeroException());

result = lastNumber / numberInDisplay;

}

if (lastOperator.equals("*"))

result = lastNumber * numberInDisplay;

if (lastOperator.equals("-"))

result = lastNumber - numberInDisplay;

if (lastOperator.equals("+"))

result = lastNumber + numberInDisplay;

return result;

}

void displayResult(double result){

setDisplayString(Double.toString(result));

lastNumber = result;

displayMode = RESULT_MODE;

clearOnNextDigit = true;

}

void displayError(String errorMessage){

setDisplayString(errorMessage);

lastNumber = 0;

displayMode = ERROR_MODE;

clearOnNextDigit = true;

}

public static void main(String args[]) {

Calculator calci = new Calculator();

Container contentPane = calci.getContentPane();

// contentPane.setLayout(new BorderLayout());

calci.setTitle("Java Swing Calculator");

calci.setSize(241, 217);

calci.pack();

calci.setLocation(400, 250);

calci.setVisible(true);

calci.setResizable(false);

}

} //End of Swing Calculator Class.

class DivideByZeroException extends Exception{

public DivideByZeroException()

{

super();

}

public DivideByZeroException(String s)

{

super(s);

}

class CustomABOUTDialog extends JDialog implements ActionListener {

JButton jbnOk;

CustomABOUTDialog(JFrame parent, String title, boolean modal){

super(parent, title, modal);

setBackground(Color.black);

JPanel p1 = new JPanel(new FlowLayout(FlowLayout.CENTER));

StringBuffer text = new StringBuffer();

text.append("Calculator Information\n\n");

text.append("Developer: Hemanth\n");

text.append("Version: 1.0");

JTextArea jtAreaAbout = new JTextArea(5, 21);

jtAreaAbout.setText(text.toString());

jtAreaAbout.setFont(new Font("Times New Roman", 1, 13));

jtAreaAbout.setEditable(false);

p1.add(jtAreaAbout);

p1.setBackground(Color.red);

getContentPane().add(p1, BorderLayout.CENTER);

JPanel p2 = new JPanel(new FlowLayout(FlowLayout.CENTER));

jbnOk = new JButton(" OK ");

jbnOk.addActionListener(this);

p2.add(jbnOk);

getContentPane().add(p2, BorderLayout.SOUTH);

setLocation(408, 270);

setResizable(false);

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e)

{

Window aboutDialog = e.getWindow();

aboutDialog.dispose();

}

);

pack();

}

public void actionPerformed(ActionEvent e)

{

if(e.getSource() == jbnOk) {

this.dispose();

}

JAVA - Circle Button

package circlebutton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JLabel;

import javax.swing.JButton;

import java.awt.event.ActionListener;

import java.awt.event.ActionEvent;

public class GuiMain{

public static void main(String[] args){

JFrame frame = new JFrame("Circle Button Demo");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JLabel circleLabel = new JLabel("Exciting circle button:");

CircleButton circleButton = new CircleButton("Click me!");

circleButton.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){

System.out.println("Clicked!");

}

});

JLabel normalLabel = new JLabel("Boring square button:");

JButton normalButton = new JButton("Okay");

JPanel panel = new JPanel();

panel.add(circleLabel);

panel.add(circleButton);

panel.add(normalLabel);

panel.add(normalButton);

frame.add(panel);

frame.setSize(300, 150);

frame.setVisible(true);

}

=================================================

package circlebutton;

import javax.swing.JButton;

import java.awt.Graphics;

import java.awt.Color;

import java.awt.Dimension;

import java.awt.geom.Point2D;

import java.awt.FontMetrics;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

public class CircleButton extends JButton{

private boolean mouseOver = false;

private boolean mousePressed = false;

public CircleButton(String text){

super(text);

setOpaque(false);

setFocusPainted(false);

setBorderPainted(false);

MouseAdapter mouseListener = new MouseAdapter(){

@Override

public void mousePressed(MouseEvent me){

if(contains(me.getX(), me.getY())){

mousePressed = true;

repaint();

}

@Override

public void mouseReleased(MouseEvent me){

mousePressed = false;

repaint();

}

@Override

public void mouseExited(MouseEvent me){

mouseOver = false;

mousePressed = false;

repaint();

}

@Override

public void mouseMoved(MouseEvent me){

mouseOver = contains(me.getX(), me.getY());

repaint();

}

};

addMouseListener(mouseListener);

addMouseMotionListener(mouseListener);

}

private int getDiameter(){

int diameter = Math.min(getWidth(), getHeight());

return diameter;

}

@Override

public Dimension getPreferredSize(){

FontMetrics metrics = getGraphics().getFontMetrics(getFont());

int minDiameter = 10 + Math.max(metrics.stringWidth(getText()), metrics.getHeight());

return new Dimension(minDiameter, minDiameter);

}

@Override

public boolean contains(int x, int y){

int radius = getDiameter()/2;

return Point2D.distance(x, y, getWidth()/2, getHeight()/2) < radius;

}

@Override

public void paintComponent(Graphics g){

int diameter = getDiameter();

int radius = diameter/2;

if(mousePressed){

g.setColor(Color.LIGHT_GRAY);

}

else{

g.setColor(Color.WHITE);

}

g.fillOval(getWidth()/2 - radius, getHeight()/2 - radius, diameter, diameter);

if(mouseOver){

g.setColor(Color.BLUE);

}

else{

g.setColor(Color.BLACK);

}

g.drawOval(getWidth()/2 - radius, getHeight()/2 - radius, diameter, diameter);

g.setColor(Color.BLACK);

g.setFont(getFont());

FontMetrics metrics = g.getFontMetrics(getFont());

int stringWidth = metrics.stringWidth(getText());

int stringHeight = metrics.getHeight();

g.drawString(getText(), getWidth()/2 - stringWidth/2, getHeight()/2 + stringHeight/4);

}

===============================

comment

In the frame class:


       CircleButton JButtonMusic=new CircleButton("");
       //JButtonMusic.setContentAreaFilled(false);
       JButtonMusic.setFocusPainted(false);
       JButtonMusic.setBorderPainted(false);
       JButtonMusic.setSize(120,70);
       imageIcon2 = new ImageIcon(musicIcon); // load the image to a imageIcon
       
       image2 = imageIcon2.getImage(); // transform it 
       newimg2 = image2.getScaledInstance(30, 30,  java.awt.Image.SCALE_SMOOTH); // scale it the smooth way  
       imageIcon2 = new ImageIcon(newimg2);  // transform it back
       JButtonMusic.setIcon( imageIcon2); 

              
       JButtonMusic.setLocation(1050,710);
       
       add(JButtonMusic);

JAVA - Search Text

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.util.ArrayList;

import java.util.List;

public class SimpleSearchEngineGUI extends JFrame {

private JTextField searchField;

private JList<String> resultList;

private DefaultListModel<String> listModel;

private List<String> dataStore; // Your data source

public SimpleSearchEngineGUI() {

setTitle("Simple Search Engine");

setSize(400, 300);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setLayout(new BorderLayout());

// Initialize data (replace with your actual data loading)

dataStore = new ArrayList<>();

dataStore.add("Apple is a fruit.");

dataStore.add("Banana is a yellow fruit.");

dataStore.add("Carrot is a vegetable.");

dataStore.add("Another apple pie recipe.");

// Search Panel

JPanel searchPanel = new JPanel();

searchField = new JTextField(20);

JButton searchButton = new JButton("Search");

searchPanel.add(searchField);

searchPanel.add(searchButton);

add(searchPanel, BorderLayout.NORTH);

// Result List

listModel = new DefaultListModel<>();

resultList = new JList<>(listModel);

JScrollPane scrollPane = new JScrollPane(resultList);

add(scrollPane, BorderLayout.CENTER);

// Event Listener

searchButton.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent e) {

performSearch();

}

});

searchField.addActionListener(new ActionListener() { // Allow Enter key to trigger search

@Override

public void actionPerformed(ActionEvent e) {

performSearch();

}

});

}

private void performSearch() {

String query = searchField.getText().toLowerCase();

listModel.clear(); // Clear previous results

if (query.isEmpty()) {

// Optionally show all data or a message

for (String item : dataStore) {

listModel.addElement(item);

}

return;

}

for (String item : dataStore) {

if (item.toLowerCase().contains(query)) {

listModel.addElement(item);

}

public static void main(String[] args) {

SwingUtilities.invokeLater(new Runnable() {

@Override

public void run() {

new SimpleSearchEngineGUI().setVisible(true);

}

});

}

JAVA - Calculator

package mainc;

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

public class MainC implements ActionListener {

private String number;

private int num;

private int num_index = 0;

private int op_index = 0;

private double[] nums = new double[100];

private char[] operations = new char[100];

private JLabel label;

private JFrame frame;

private JPanel panel;

public MainC() {

frame = new JFrame();

// Create all buttons needed for the calculator

JButton b1 = new JButton("1");

b1.addActionListener(this);

JButton b2 = new JButton("2");

b2.addActionListener(this);

JButton b3 = new JButton("3");

b3.addActionListener(this);

JButton b4 = new JButton("4");

b4.addActionListener(this);

JButton b5 = new JButton("5");

b5.addActionListener(this);

JButton b6 = new JButton("6");

b6.addActionListener(this);

JButton b7 = new JButton("7");

b7.addActionListener(this);

JButton b8 = new JButton("8");

b8.addActionListener(this);

JButton b9 = new JButton("9");

b9.addActionListener(this);

JButton b0 = new JButton("0");

b0.addActionListener(this);

JButton bp = new JButton("+");

bp.addActionListener(this);

JButton bm = new JButton("-");

bm.addActionListener(this);

JButton bmu = new JButton("*");

bmu.addActionListener(this);

JButton bd = new JButton("/");

bd.addActionListener(this);

JButton bc = new JButton("C");

bc.addActionListener(this);

JButton be = new JButton("=");

be.addActionListener(this);

// Label keeping track of user input

label = new JLabel("0");

// Create new JPanel with all buttons and the label

panel = new JPanel();

panel.setBorder(BorderFactory.createEmptyBorder(100, 100, 200, 200));

panel.setLayout(new GridLayout(3, 4));

panel.add(label);

panel.add(bc);

panel.add(b1);

panel.add(b2);

panel.add(b3);

panel.add(b4);

panel.add(b5);

panel.add(b6);

panel.add(b7);

panel.add(b8);

panel.add(b9);

panel.add(b0);

panel.add(bp);

panel.add(bm);

panel.add(bmu);

panel.add(bd);

panel.add(be);

frame.add(panel, BorderLayout.CENTER);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setTitle("Calculator");

frame.pack();

frame.setVisible(true);

}

public static void main(String[] args) {

new MainC();

}

@Override

public void actionPerformed(ActionEvent e) {

JButton clicked = (JButton) e.getSource();

String val = clicked.getText();

char newval = val.charAt(0);

// Handle Clearing and Entering Numbers

// Clear

if (val.equals("C")) {

number = "";

label.setText("0");

num = 0;

operations = new char[100];

nums = new double[100];

num_index = 0;

op_index = 0;

}

// First number entered

else if (label.getText().equals("0")) {

number = val;

label.setText(number);

num = Integer.parseInt(clicked.getText());

}

// Any other number

else if (newval != '+' && newval != '-' && newval != '*' && newval != '/' && newval != '=') {

label.setText(label.getText() + val);

number += val;

num = Integer.parseInt(number);

}

// Handle Operations

if (newval == '+') {

label.setText(label.getText() + '+');

number = "";

nums[num_index] = num;

num_index++;

operations[op_index] = '+';

op_index++;

num = 0;

} else if (newval == '-') {

label.setText(label.getText() + '-');

number = "";

nums[num_index] = num;

num_index++;

operations[op_index] = '-';

op_index++;

num = 0;

} else if (newval == '*') {

label.setText(label.getText() + '*');

number = "";

nums[num_index] = num;

num_index++;

operations[op_index] = '*';

op_index++;

num = 0;

} else if (newval == '/') {

label.setText(label.getText() + '/');

number = "";

nums[num_index] = num;

num_index++;

operations[op_index] = '/';

op_index++;

num = 0;

} else if (newval == '=') {

nums[num_index] = num;

num_index++;

int nLength = nums.length;

int oLength = operations.length;

for (int i = 0; i < oLength; i++) {

if (operations[i] == '*' || operations[i] == '/') {

double result = 0;

if (operations[i] == '*') {

result = nums[i] * nums[i + 1];

} else if (operations[i] == '/') {

if (nums[i + 1] == 0) {

label.setText("Division by zero is not allowed.");

return;

}

result = (double)nums[i] / nums[i + 1];

}

// Update arrays: replace nums[i] with the result, shift the rest left

nums[i] = result;

nums = shiftLeft(nums, i + 1);

operations = shiftLeft(operations, i);

// Adjust lengths

nLength--;

oLength--;

// Stay at the same index after shifting

i--;

}

// Step 2: Handle Addition (+) and Subtraction (-)

double result = nums[0];

for (int i = 0; i < oLength; i++) {

if (operations[i] == '+') {

result += nums[i + 1];

} else if (operations[i] == '-') {

result -= nums[i + 1];

}

label.setText("" + result);

number = "";

num = 0;

operations = new char[100];

nums = new double[100];

num_index = 0;

op_index = 0;

}

// Helper method to shift elements in an int array to the left

public static double[] shiftLeft(double[] arr, int startIndex) {

double[] newArr = new double[arr.length - 1];

for (int i = 0; i < startIndex; i++) {

newArr[i] = arr[i];

}

for (int i = startIndex; i < newArr.length; i++) {

newArr[i] = arr[i + 1];

}

return newArr;

}

// Helper method to shift elements in a char array to the left

public static char[] shiftLeft(char[] arr, int startIndex) {

char[] newArr = new char[arr.length - 1];

for (int i = 0; i < startIndex; i++) {

newArr[i] = arr[i];

}

for (int i = startIndex; i < newArr.length; i++) {

newArr[i] = arr[i + 1];

}

return newArr;

}

JAVAFX - Fractal Mandelbrot

package javafxmandelbrotset;

import javafx.application.Application;

import javafx.scene.Scene;

import javafx.scene.canvas.Canvas;

import javafx.scene.canvas.CanvasBuilder;

import javafx.scene.canvas.GraphicsContext;

import javafx.scene.layout.Pane;

import javafx.scene.paint.Color;

import javafx.stage.Stage;

/**

* Mandelbrot set with JavaFX.

* @author hameister

public class JavaFXMandelbrotSet extends Application {

// Size of the canvas for the Mandelbrot set

private static final int CANVAS_WIDTH = 740;

private static final int CANVAS_HEIGHT = 605;

// Left and right border

private static final int X_OFFSET = 25;

// Top and Bottom border

private static final int Y_OFFSET = 25;

// Values for the Mandelbro set

private static double MANDELBROT_RE_MIN = -2;

private static double MANDELBROT_RE_MAX = 1;

private static double MANDELBROT_IM_MIN = -1.2;

private static double MANDELBROT_IM_MAX = 1.2;

@Override

public void start(Stage primaryStage) {

Pane fractalRootPane = new Pane();

Canvas canvas = CanvasBuilder

.create()

.height(CANVAS_HEIGHT)

.width(CANVAS_WIDTH)

.layoutX(X_OFFSET)

.layoutY(Y_OFFSET)

.build();

paintSet(canvas.getGraphicsContext2D(),

MANDELBROT_RE_MIN,

MANDELBROT_RE_MAX,

MANDELBROT_IM_MIN,

MANDELBROT_IM_MAX);

fractalRootPane.getChildren().add(canvas);

Scene scene = new Scene(fractalRootPane, CANVAS_WIDTH + 2 * X_OFFSET, CANVAS_HEIGHT + 2 * Y_OFFSET);

scene.setFill(Color.BLACK);

primaryStage.setTitle("Mandelbrot Set");

primaryStage.setScene(scene);

primaryStage.show();

}

private void paintSet(GraphicsContext ctx, double reMin, double reMax, double imMin, double imMax) {

double precision = Math.max((reMax - reMin) / CANVAS_WIDTH, (imMax - imMin) / CANVAS_HEIGHT);

int convergenceSteps = 50;

for (double c = reMin, xR = 0; xR < CANVAS_WIDTH; c = c + precision, xR++) {

for (double ci = imMin, yR = 0; yR < CANVAS_HEIGHT; ci = ci + precision, yR++) {

double convergenceValue = checkConvergence(ci, c, convergenceSteps);

double t1 = (double) convergenceValue / convergenceSteps;

double c1 = Math.min(255 * 2 * t1, 255);

double c2 = Math.max(255 * (2 * t1 - 1), 0);

if (convergenceValue != convergenceSteps) {

ctx.setFill(Color.color(c2 / 255.0, c1 / 255.0, c2 / 255.0));

} else {

ctx.setFill(Color.PURPLE); // Convergence Color

}

ctx.fillRect(xR, yR, 1, 1);

}

/**

* Checks the convergence of a coordinate (c, ci) The convergence factor

* determines the color of the point.

private int checkConvergence(double ci, double c, int convergenceSteps) {

double z = 0;

double zi = 0;

for (int i = 0; i < convergenceSteps; i++) {

double ziT = 2 * (z * zi);

double zT = z * z - (zi * zi);

z = zT + c;

zi = ziT + ci;

if (z * z + zi * zi >= 4.0) {

return i;

}

return convergenceSteps;

}

public static void main(String[] args) {

launch(args);

}

JAVA - Fractal JPanel

package fractalpael;

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import javax.swing.JComponent;

import javax.swing.JPanel;

import javax.swing.JFrame;

public class FractalPanel extends JPanel {

final FractalSquare square = new FractalSquare(450, 350);

public FractalPanel() {

add(square);

}

public static void main(String[] args) {

FractalPanel fractalPanel = new FractalPanel();

JFrame frame = new JFrame();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.add(fractalPanel);

frame.pack();

frame.setVisible(true);

Thread squareThread = new Thread(() -> {

try {

fractalPanel.square.render();

} catch (InterruptedException e) {

System.err.println("Interrupted");

}

});

squareThread.start();

}

class Fractal extends JComponent {

final BufferedImage image;

final Graphics2D offscreenGraphics;

public Fractal(int width, int height) {

setPreferredSize(new Dimension(width, height));

image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

offscreenGraphics = image.createGraphics();

}

// Copy the offscreen image to the main graphics context

public void paint(Graphics g) {

Graphics2D g2 = (Graphics2D) g;

synchronized (image) { // synchronize with the render thread

g2.drawImage(image, 0, 0, null);

}

class FractalSquare extends Fractal {

public FractalSquare(int width, int height) {

super(width, height);

}

public void render() throws InterruptedException {

drawSquares(getWidth() / 2, getHeight() / 2, 100, 7);

}

public void drawSquares(int x, int y, int side, int size) throws InterruptedException {

// Sleep for 10ms between frames

Thread.sleep(10);

if (size > 2) {

size--;

synchronized (image) { // synchronize with the draw thread

offscreenGraphics.setColor(Color.BLUE);

System.out.printf("Filling [%d, %d, %d, %d]\n", x - side / 2, y - side / 2, side, side);

offscreenGraphics.fillRect(x - side / 2, y - side / 2, side, side);

}

// Tell Swing that we've updated the image and it needs to be redrawn

repaint();

side = side / 2;

x = x - side;

y = y - side;

drawSquares(x, y, side, size);

drawSquares(x + side * 2, y, side, size);

drawSquares(x, y + side * 2, side, size);

drawSquares(x + side * 2, y + side * 2, side, size);

}

Minggu, 14 September 2025

JAVA - Traffic Light

File : GUIGen.java

package gui;

import java.awt.Container;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.Box;

import javax.swing.JButton;

import javax.swing.JFrame;

/**

* @author ajb

public class GUIGen extends JFrame implements ActionListener{

GenPanel panel = new GenPanel();

JButton stop;

JButton go;

GUIGen(){

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.setSize(300,300);

this.setLocationRelativeTo(null);

Container vert = Box.createVerticalBox();

Container hoz = Box.createHorizontalBox();

stop = new JButton("Stop");

go = new JButton(" Go ");

stop.addActionListener(this);

go.addActionListener(this);

hoz.add(stop);

hoz.add(go);

vert.add(panel);

vert.add(hoz);

this.add(vert);

this.setVisible(true);

}

/**

* @param args the command line arguments

public static void main(String[] args) {

// TODO code application logic here

new GUIGen();

}

@Override

public void actionPerformed(ActionEvent ae) {

if(ae.getSource()==stop) {

panel.setRed();

}

if(ae.getSource()==go) {

panel.setGreen();

}

repaint();

}

========================================

File : GenPanel,java

package gui;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import javax.swing.JPanel;

public class GenPanel extends JPanel {

Color light = Color.RED;

public void setRed() {

light = Color.RED;

}

public void setGreen() {

light = Color.GREEN;

}

@Override

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2 = (Graphics2D) g;

g2.setColor(Color.BLACK);

g2.fillRect(100, 10, 100, 100);

g2.setColor(light);

g2.fillOval(100,10,100,100);

}

JAVA - Ease Movement Object

package animatedobjectpanel;

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

public class AnimatedObjectPanel extends JPanel implements ActionListener {

private int objectX = 50;

private int objectY = 50;

private int targetX = 300;

private int animationDuration = 1000; // milliseconds

private long startTime;

private Timer timer;

public AnimatedObjectPanel() {

timer = new Timer(15, this); // 15ms delay for ~60fps

timer.start();

startTime = System.currentTimeMillis();

}

@Override

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2d = (Graphics2D) g;

g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

g2d.setColor(Color.BLUE);

g2d.fillRect(objectX, objectY, 50, 50); // Draw the animated object

}

@Override

public void actionPerformed(ActionEvent e) {

long currentTime = System.currentTimeMillis();

long elapsedTime = currentTime - startTime;

if (elapsedTime < animationDuration) {

double progress = (double) elapsedTime / animationDuration;

// Apply an easing function (e.g., ease-out quadratic)

double easedProgress = 1 - Math.pow(1 - progress, 2);

objectX = (int) (50 + (targetX - 50) * easedProgress);

} else {

objectX = targetX; // Ensure it reaches the final position

timer.stop(); // Stop the timer when animation is complete

}

repaint(); // Request a redraw

}

public static void main(String[] args) {

JFrame frame = new JFrame("2D Animation with Easing");

AnimatedObjectPanel panel = new AnimatedObjectPanel();

frame.add(panel);

frame.setSize(400, 300);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

JAVA - Collision Detection

package grafico;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.Timer;

public class grafico extends JPanel implements ActionListener {

Timer tm = new Timer(5, this);

int x1 = 0;

int x2 = 0;

int velX1 = 1;

int velX2 = 1;

public void paintComponent(Graphics g) {

super.paintComponent(g);

g.setColor(Color.RED);

g.fillRect(x1, 160, 10, 10);

g.setColor(Color.BLUE);

g.fillRect(x2, x2, 10, 10);

}

public void actionPerformed(ActionEvent e) {

if (x1 < 0 || x1 > 400)

velX1 = -velX1;

x1 = x1 + velX1;

if (x2 < 0 || x2 > 300)

velX2 = -velX2;

x2 = x2 + velX2;

if( checkCollition() ) { // only two show the Idea.

velX2 = -velX2; // this code is not simulating a

x2 = x2 + velX2; // collision. You should change it

// in the future.

}

repaint();

}

private boolean checkCollition() {

return Math.abs(x1-x2) < 10 && Math.abs(160-x2) < 10;

}

public static void main(String[] args) {

grafico t = new grafico();

JFrame jf = new JFrame();

jf.setTitle("Tutorial");

jf.setSize(600, 400);

jf.setVisible(true);

jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

jf.add(t);

t.tm.start();

}

JAVA - Physics Falling Ball

File : PhysicsSimulation.java

package physicssimulation;

import javax.swing.*;

import java.awt.*;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.util.ArrayList;

import java.util.List;

public class PhysicsSimulation extends JFrame {

private final SimulationPanel simulationPanel;

private final Timer timer;

public PhysicsSimulation() {

setTitle("2D Physics Simulation");

setSize(800, 600);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

setLocationRelativeTo(null);

simulationPanel = new SimulationPanel();

add(simulationPanel);

timer = new Timer(16, new ActionListener() { // ~60 FPS

@Override

public void actionPerformed(ActionEvent e) {

simulationPanel.updatePhysics();

simulationPanel.repaint();

}

});

timer.start();

}

public static void main(String[] args) {

SwingUtilities.invokeLater(() -> new PhysicsSimulation().setVisible(true));

}

class SimulationPanel extends JPanel {

private final List<SimulatedObject> objects;

private final double gravity = 0.5; // Example gravity

public SimulationPanel() {

objects = new ArrayList<>();

// Add some initial objects

objects.add(new SimulatedObject(100, 100, 20, 0, 0));

objects.add(new SimulatedObject(300, 50, 30, 0, 0));

}

public void updatePhysics() {

for (SimulatedObject obj : objects) {

// Apply gravity

obj.velocityY += gravity;

// Update position

obj.x += obj.velocityX;

obj.y += obj.velocityY;

// Simple boundary collision (bounce)

if (obj.y + obj.size > getHeight()) {

obj.y = getHeight() - obj.size;

obj.velocityY *= -0.8; // Reduce velocity on bounce

}

if (obj.x + obj.size > getWidth() || obj.x < 0) {

obj.velocityX *= -1;

}

@Override

protected void paintComponent(Graphics g) {

super.paintComponent(g);

Graphics2D g2d = (Graphics2D) g;

g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

// Draw objects

for (SimulatedObject obj : objects) {

g2d.fillOval((int) obj.x, (int) obj.y, (int) obj.size, (int) obj.size);

}

======================================================

File : SimulatedObject.java

package physicssimulation;

class SimulatedObject {

double x, y;

double size;

double velocityX, velocityY;

public SimulatedObject(double x, double y, double size, double velocityX, double velocityY) {

this.x = x;

this.y = y;

this.size = size;

this.velocityX = velocityX;

this.velocityY = velocityY;

}