13.1.3 Klasse block2.BinaerFloatApplet

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.BinaerFloatApplet

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 BinaerFloatApplet extends JApplet implements ActionListener {

private JTextField eingabeText;
private JButton enterButton;
private JButton nanButton;
private JButton negativeInfinityButton;
private JButton positiveInfinityButton;
private JButton maxButton;
private JButton minButton;
private int[] bits;
private String eingabeWert = "1";
private int vorzeichen;
private float mantisse;
private int exponent;
float wert = 0;
public BinaerFloatApplet() {
JPanel buttonPanel;
bits = new int[32];
bits = decode(1.0f);
// 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);
nanButton = new JButton("N.a.N.");
nanButton.addActionListener(this);
negativeInfinityButton = new JButton("-Infinity");
negativeInfinityButton.addActionListener(this);
positiveInfinityButton = new JButton("+Infinity");
positiveInfinityButton.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(nanButton);
optPanel.add(minButton);
optPanel.add(maxButton);
optPanel.add(negativeInfinityButton);
optPanel.add(positiveInfinityButton);
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 = 100; // Horizontaler Offset für Bitsdarstellung
int dezimalStart = hoffSet * 2;
g.setColor(Color.blue);
g.drawString("32 Bit float:", dezimalStart, 25);
g.drawString(eingabeWert + " = ", dezimalStart, 45);
dezimalStart += 10+(eingabeWert.length()) * hoffSet;
g.drawString("(-1)", dezimalStart, 45);
dezimalStart += 3 * hoffSet;
g.drawString(Integer.toString(bits[31]), dezimalStart, 40);
dezimalStart += 1 * hoffSet;
g.drawString("*2", dezimalStart, 45);
dezimalStart += 2 * hoffSet;
g.drawString("(", dezimalStart, 40);
dezimalStart += 1 * hoffSet;
g.drawString(Integer.toString(exponent), dezimalStart, 40);
dezimalStart += Integer.toString(exponent).length() * hoffSet;
g.drawString("-127)", dezimalStart, 40);
dezimalStart += 5 * hoffSet;
g.drawString("*", dezimalStart, 45);
dezimalStart += 1 * hoffSet;
g.drawString(Float.toString(mantisse), dezimalStart, 45);
int rows = 0;
int cols;
g.setColor(Color.black);
g.drawString("Vorzeichen : ",20,60 + voffset * rows);
String vorz = "-1*";
if (bits[31] == 0) {
vorz = "1*";
}
g.drawString(Integer.toString(bits[31]),
binaerStart,
60 + voffset * rows);
rows++;
g.setColor(Color.black);
g.drawString("Exponent : ",
20,
60 + voffset * rows);
cols = 0;
for (int i = 30; i >= 23; i--) {
g.drawString(Integer.toString(bits[i]),
binaerStart + 10 * cols,
60 + voffset * rows);
if (cols != 7) {
cols++;
} else {
cols = 0;
rows++;
}
}
g.drawString("Mantisse :",20,60 + voffset * rows);
cols = 0;
g.setColor(Color.blue);
g.drawString("1",
binaerStart + 10 * cols,
60 + voffset * rows);
g.setColor(Color.black);
cols++;
for (int i = 22; i >= 0; i--) {
g.drawString(Integer.toString(bits[i]),
binaerStart + 10 * cols,
60 + voffset * rows);
if (cols != 7) {
cols++;
} else {
cols = 0;
rows++;
}
}
g.setColor(Color.blue);
g.fill3DRect(20,(70 + voffset * rows), 200, 40, rootPaneCheckingEnabled);
rows++;
g.setColor(Color.black);
g.drawString("Die führende 1 der Mantisse ist",
20,70 + voffset * rows);
rows++;
g.drawString("nicht Teil der Datenstruktur!",
20, 70 + voffset * rows);

}
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == nanButton) { //>> Button aufgerufen
eingabeWert = eingabeText.getText();
wert = Float.NaN;
}
if (source == minButton) {
wert = Float.MIN_VALUE;
}
if (source == maxButton) {
wert = Float.MAX_VALUE;
}
if (source == negativeInfinityButton) {
wert = Float.NEGATIVE_INFINITY;
}
if (source == positiveInfinityButton) {
wert = Float.POSITIVE_INFINITY;
}
if (source == enterButton) {
try {
eingabeWert = eingabeText.getText();
wert = Float.parseFloat(eingabeWert);
} catch (java.lang.NumberFormatException ex) {
// Fehlerbehandlung bei fehlerhafter Eingabe
eingabeText.setText("Fehler");
wert = 0;
}
}
bits = decode(wert);
eingabeText.setText(Float.toString(wert));
eingabeWert = Float.toString(wert);
repaint();
}
public int[] decode(float s) {
int size = 32;
int t = Float.floatToRawIntBits(s);
mantisse = Float.intBitsToFloat((t & 0x007FFFFF) | 0x40000000);
mantisse /= 2;

System.out.println("Binär Mantisse: "
+ Integer.toBinaryString(Float.floatToRawIntBits(mantisse)));
exponent = (t & 0x7F800000) >> 23;
vorzeichen = (t & 0x80000000) >> 31;
System.out.println("Mantisse:" + mantisse);
System.out.println("Exponent:" + (exponent - 127));
System.out.println("Vorzeichen:" + vorzeichen);
int[] stellen = new int[size];
for (int i = 0; i < size; i++) {
stellen[i] = (1 & t);
t >>>= 1;
}
return stellen;
}
public int[] decode(double s) {
int size = 64;
long t = Double.doubleToRawLongBits(s);
int[] stellen = new int[size];
for (int i = 0; i < size; i++) {
stellen[i] = (int) (1 & t);
t >>>= 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("BinaerFloatApplet-Standalone");
f.add(new block2.BinaerFloatApplet());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.pack();
f.setSize(400, 300);
f.setVisible(true);
}
}