79 lines
3.0 KiB
Java
79 lines
3.0 KiB
Java
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package jpl.test;
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/**
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* CelsiusConverter.java is a 1.4 application that
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* demonstrates the use of JButton, JTextField and
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* JLabel. It requires no other files.
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*/
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import java.awt.*;
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import java.awt.event.*;
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import javax.swing.*;
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public class CelsiusConverter implements ActionListener {
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JFrame converterFrame;
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JPanel converterPanel;
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JTextField tempCelsius;
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JLabel celsiusLabel, fahrenheitLabel;
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JButton convertTemp;
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public CelsiusConverter() { // initially locate the window at top-left of desktop
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this(0, 0);
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}
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public CelsiusConverter(int left, int top) { // initially locate the window at top-left of desktop
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// create and set up the window
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converterFrame = new JFrame("Convert Celsius to Fahrenheit");
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converterFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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converterFrame.setSize(new Dimension(120, 40));
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converterFrame.setLocation(left, top);
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// create and set up the panel
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converterPanel = new JPanel(new GridLayout(2, 2));
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// create widgets
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tempCelsius = new JTextField(2);
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celsiusLabel = new JLabel("Celsius", SwingConstants.LEFT);
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celsiusLabel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
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//
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convertTemp = new JButton("Convert");
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fahrenheitLabel = new JLabel("Fahrenheit", SwingConstants.LEFT);
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// listen to events from the Convert button
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convertTemp.addActionListener(this);
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// add the widgets to the container
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converterPanel.add(tempCelsius);
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converterPanel.add(celsiusLabel);
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converterPanel.add(convertTemp);
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converterPanel.add(fahrenheitLabel);
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fahrenheitLabel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
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converterFrame.getRootPane().setDefaultButton(convertTemp); // make "convert" the window's default button
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// add the panel to the window
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converterFrame.getContentPane().add(converterPanel, BorderLayout.CENTER);
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// display the window
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converterFrame.pack();
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converterFrame.setVisible(true);
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}
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public void actionPerformed(ActionEvent event) {
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// parse degrees Celsius as a double
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double tC = (Double.parseDouble(tempCelsius.getText()));
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//
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// convert to Fahrenheit (in Java)
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// int tempFahr = (int) (tC * 1.8 + 32);
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//
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// convert to Fahrenheit (in Prolog, via JPL)
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int tempFahr = ((jpl.Float) jpl.Query.oneSolution("TF is ? * 1.8 + 32", new jpl.Term[] {new jpl.Float(tC)}).get("TF")).intValue();
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//
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// display the result
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fahrenheitLabel.setText(tempFahr + " Fahrenheit");
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}
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public static void spawnGUI(final int left, final int top) {
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// schedule a job for the event-dispatching thread: create and show an instance of this application at (left,top)
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javax.swing.SwingUtilities.invokeLater(new Runnable() {
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int x = left;
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int y = top;
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public void run() {
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new CelsiusConverter(x, y); // can we be sure this won't be garbage collected?
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}
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});
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}
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public static void main(String[] args) {
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// just for fun, we ask Prolog to start five instances of this class (at stepped offsets from top-left of display)
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jpl.Query.allSolutions("between(1, 5, N), X is 10*N, Y is 20*N, jpl_call('jpl.test.CelsiusConverter', spawnGUI, [X,Y], _)");
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}
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}
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