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12.1.5 Klasse IntShiftApplet

Das Applet

Starten des Applets als Hauptprogramm

Laden Sie die jar Datei Kurs1Applet.jar.

Die Anwendung kann von der Kommandozeile mit dem folgenden Kommando gestartet werden.

java -cp Kurs1Applet.jar block2.IntShiftApplet

Die Datei Kurs1Applet.jar muss im gleichen Verzeichnis sein 

Der Quellcode

package block2;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JApplet;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
/**
*
* @author sschneid
* @version 1.2
*
* Copyright (c) 2013, Dr. Stefan Schneider, schneider4me.de
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those
* of the authors and should not be interpreted as representing official policies,
* either expressed or implied, of the FreeBSD Project.
*/
public class IntShiftApplet extends JApplet implements ActionListener {

private JTextField eingabeText;
private JButton enterButton;
private JButton leftShiftNullFillButton;
private JButton rightShiftButton;
private JButton rightShiftNullFillButton;
private JButton maxButton;
private JButton minButton;
private int[] bits;
private String eingabeWert = "1";
private int vorzeichen;
private float mantisse;
private int exponent;
int wert = 1;
public IntShiftApplet() {
JPanel buttonPanel;
bits = new int[32];
bits = decode(1);
// Erzeugen der Buttons und Texteingabefeld
JLabel eingabeLabel = new JLabel("Eingabewert: ");
eingabeText = new JTextField(eingabeWert);
eingabeText.setPreferredSize(new Dimension(100, 20));
enterButton = new JButton("Enter");
enterButton.addActionListener(this);
leftShiftNullFillButton = new JButton("a << 1");
leftShiftNullFillButton.addActionListener(this);
rightShiftButton = new JButton("a >> 1");
rightShiftButton.addActionListener(this);
rightShiftNullFillButton = new JButton("a >>> 1");
rightShiftNullFillButton.addActionListener(this);
maxButton = new JButton("MAX_VALUE");
maxButton.addActionListener(this);
minButton = new JButton("MIN_VALUE");
minButton.addActionListener(this);
JPanel optPanel = new JPanel();
optPanel.setLayout(new BoxLayout(optPanel, BoxLayout.Y_AXIS));
optPanel.add(minButton);
optPanel.add(maxButton);
optPanel.add(leftShiftNullFillButton);
optPanel.add(rightShiftButton);
optPanel.add(rightShiftNullFillButton);
buttonPanel = new JPanel();
buttonPanel.add(eingabeLabel);
buttonPanel.add(eingabeText);
buttonPanel.add(enterButton);
JPanel centerPanel = new JPanel();
centerPanel.setSize(500, 500);
Container myPane = getContentPane();
myPane.add(buttonPanel, BorderLayout.SOUTH);
myPane.add(optPanel, BorderLayout.EAST);
myPane.add(centerPanel, BorderLayout.CENTER);
}
@Override
public void paint(Graphics g) {
super.paint(g);
int hoffSet = 8; // Ziffernbreite
int voffset = 15; // Zeilenabstand
int binaerStart = 80; // Horizontaler Offset für Bitsdarstellung
int dezimalStart = hoffSet * 2;
int vertikal = 25;
g.setColor(Color.blue);
g.drawString("32 Bit Integer", dezimalStart, vertikal);
g.setColor(Color.black);
vertikal += hoffSet*2;
g.drawString("Dezimal: a = "+ eingabeWert, dezimalStart, vertikal);
vertikal += hoffSet*2;
g.drawString("Binär: a =", dezimalStart, vertikal);

int rows = 0;
int cols = 0;
for (int i = (bits.length - 1); i >= 0; i--) {
if (i == bits.length - 1) {
g.setColor(Color.red);
} else {
g.setColor(Color.black);
}
g.drawString(Integer.toString(bits[i]),
binaerStart + 10 * cols,
vertikal+ 15*rows);
if (cols != 7) cols++;
else {cols=0; rows++;}
}
}
/**
* Diese Methode decodiert Benutzer
* @param e
*/
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == leftShiftNullFillButton) {
eingabeWert = eingabeText.getText();
wert = wert << 1;
}
if (source == minButton) {
wert = Integer.MIN_VALUE;
}
if (source == maxButton) {
wert = Integer.MAX_VALUE;
}
if (source == rightShiftButton) {
wert = wert >> 1;
}
if (source == rightShiftNullFillButton) {
wert = wert >>> 1;
}
if (source == enterButton) {
try {
eingabeWert = eingabeText.getText();
wert = Integer.parseInt(eingabeWert);
} catch (java.lang.NumberFormatException ex) {
// Fehlerbehandlung bei fehlerhafter Eingabe
eingabeText.setText("Fehler");
wert = 0;
}
}
bits = decode(wert);
eingabeText.setText(Integer.toString(wert));
eingabeWert = Integer.toString(wert);
repaint();
}
public static int[] decode(int s) {
int size = 32;
int[] stellen = new int[size];
for (int i = 0; i < size; i++) {
stellen[i] = (1 & s);
s >>>= 1;
}
return stellen;
}
/**
* Starten der Anwendung als eigenständiges Programm
*
* @param args
*/
public static void main(String[] args) {
// Es wird ein JFrame benötigt, in das das Applet als Komponente
// gesteckt wird.
JFrame f = new JFrame("IntShiftApplet-Standalone");
f.add(new block2.IntShiftApplet());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setSize(400, 300);
f.setVisible(true);
}
}

 



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