This is my first attempt at a program (outside of school) and I was trying to implement and learn polymorphism on a conversion calculator for volumes and weights.
I found myself using long switch statements in the GUI to test user inputs against the units in order to make the calculations. Is there a better alternative to using switch statements here that might shorten the code, make it more readable and possibly improve efficiency?
Did I make good use of polymorphism?
I am open to any constructive criticism but again, I'm learning so please offer an explanation with your criticism/suggestions.
public class ConversionLayout {
NumberFormat df = new DecimalFormat("#.#####");
private JRadioButton volume = new JRadioButton("volume");
private JRadioButton weight = new JRadioButton("weight");
private JComboBox<String> selection1 = new JComboBox<String>();
private JComboBox<String> selection2 = new JComboBox<String>();
private DefaultComboBoxModel<String> unitSet1 = new DefaultComboBoxModel<String>();
private DefaultComboBoxModel<String> unitSet2 = new DefaultComboBoxModel<String>();
private JTextField userInput1;
private JTextField userInput2;
private JLabel topLabel;
private JLabel equals;
private JPanel topPanel;
private JPanel calcInput;
private JPanel radioPanel;
private String[] units = { "ml", "litre", "oz", "cup", "pint", "tbsp",
"tsp", "gallon", "quart" };
private String[] units1 = { "g", "kg", "oz", "lb" };
private String unit1;
private String unit2;
private String result;
private double amountValue;
private Conversion ml = new ConvertFromMillilitre();
private Conversion cup = new ConvertFromCup();
private Conversion gallon = new ConvertFromGallon();
private Conversion litre = new ConvertFromLitre();
private Conversion oz = new ConvertFromOz();
private Conversion pint = new ConvertFromPint();
private Conversion quart = new ConvertFromQuart();
private Conversion tbsp = new ConvertFromTbsp();
private Conversion tsp = new ConvertFromTsp();
private Conversion g = new ConvertFromGram();
private Conversion kg = new ConvertFromKilogram();
private Conversion ozWeight = new ConvertFromOzWeight();
private Conversion lb = new ConvertFromPound();
public ConversionLayout() {
equals = new JLabel("=");
equals.setHorizontalAlignment(SwingConstants.CENTER);
userInput1 = new JTextField();
userInput2 = new JTextField();
for (int i = 0; i < units.length; i++) {
unitSet1.addElement(units[i]);
unitSet2.addElement(units[i]);
}
selection1.setModel(unitSet1);
selection2.setModel(unitSet2);
ButtonGroup group = new ButtonGroup();
group.add(volume);
group.add(weight);
volume.setSelected(true);
radioPanel = new JPanel(new GridLayout(0, 2));
radioPanel.add(volume);
radioPanel.add(weight);
volume.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
unitSet1.removeAllElements();
unitSet2.removeAllElements();
for (int i = 0; i < units.length; i++) {
unitSet1.addElement(units[i]);
unitSet2.addElement(units[i]);
}
}
});
weight.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
unitSet1.removeAllElements();
unitSet2.removeAllElements();
for (int i = 0; i < units1.length; i++) {
unitSet1.addElement(units1[i]);
unitSet2.addElement(units1[i]);
}
}
});
setDefaultValues("ml", "ml");
calcInput = new JPanel(new GridLayout(1, 5));
calcInput.add(selection1);
calcInput.add(userInput1);
calcInput.add(equals);
calcInput.add(selection2);
calcInput.add(userInput2);
topLabel = new JLabel("Please enter your selections below:");
topPanel = new JPanel();
topPanel.add(topLabel);
unitSelections();
UserEntries entry = new UserEntries();
userInput1.addActionListener(entry);
userInput2.addActionListener(entry);
}// end layout constructor
private void setDefaultValues(String val1, String val2) {
if (unit1 == null) {
this.unit1 = val1;
this.unit2 = val2;
}
}
// ItemListener to set the value of the unit1 and unit2 fields based on user
// selections
private void unitSelections() {
selection1.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if (e.getStateChange() == ItemEvent.SELECTED) {
String selection = selection1.getSelectedItem().toString();
unit1 = selection;
}
}
});
selection2.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if (e.getStateChange() == ItemEvent.SELECTED) {
String selection = selection2.getSelectedItem().toString();
unit2 = selection;
}
}
});
}
// sets the values for userInput to each conversion unit
private void setValues(double userInput) {
ml.setValue(userInput);
ml.getValue();
cup.setValue(userInput);
cup.getValue();
gallon.setValue(userInput);
gallon.getValue();
litre.setValue(userInput);
litre.getValue();
oz.setValue(userInput);
oz.getValue();
pint.setValue(userInput);
pint.getValue();
quart.setValue(userInput);
quart.getValue();
tbsp.setValue(userInput);
tbsp.getValue();
tsp.setValue(userInput);
tsp.getValue();
tsp.setValue(userInput);
tsp.getValue();
g.setValue(userInput);
g.getValue();
kg.setValue(userInput);
kg.getValue();
ozWeight.setValue(userInput);
ozWeight.getValue();
lb.setValue(userInput);
lb.getValue();
}
// class for setting user input values on either JTextField
private class UserEntries implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
//if the volume JRadioButton is selected we will run the switch on volume units.
if (volume.isSelected()) {
// if userInput1 triggers ActionEvent we check for unit1 value and
// convert to unit2 value
if (e.getSource() == userInput1) {
String value = userInput1.getText();
// ensure entry is a numerical value
try {
amountValue = Double.parseDouble(value);
if (amountValue < 0) {
throw new NumberFormatException();
}
} catch (NumberFormatException ex) {
JOptionPane.showMessageDialog(userInput1,
"Please enter a numeric value to convert.");
}
// sets the userInput value to the unit1
setValues(amountValue);
switch (unit1) {
case "ml":
result = String.valueOf(ml.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "cup":
result = String.valueOf(cup.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "gallon":
result = String.valueOf(gallon.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "litre":
result = String.valueOf(litre.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "oz":
result = String.valueOf(oz.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "pint":
result = String.valueOf(pint.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "quart":
result = String.valueOf(quart.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "tbsp":
result = String.valueOf(tbsp.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "tsp":
result = String.valueOf(tsp.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
}//end switch
// if userInput2 triggers ActionEvent we check for unit2
// value
// and convert to unit1 value
} else if (e.getSource() == userInput2) {
String value = userInput2.getText();
try {
amountValue = Double.parseDouble(value);
if (amountValue < 0) {
throw new NumberFormatException();
}
} catch (NumberFormatException ex) {
JOptionPane
.showMessageDialog(userInput2,
"Please enter a positive numeric value to convert.");
}
// sets the userInput value to the units
setValues(amountValue);
switch (unit2) {
case "ml":
result = String.valueOf(ml.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "cup":
result = String.valueOf(cup.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "gallon":
result = String.valueOf(gallon.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "litre":
result = String.valueOf(litre.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "oz":
result = String.valueOf(oz.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "pint":
result = String.valueOf(pint.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "quart":
result = String.valueOf(quart.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "tbsp":
result = String.valueOf(tbsp.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "tsp":
result = String.valueOf(tsp.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
}//end switch
}//end inner if/else
//if the weight JRadioButton is selected we will run the switch on weight units.
} else if (weight.isSelected()) {
// if userInput1 triggers ActionEvent we check for unit1
// value and convert to unit2 value
if (e.getSource() == userInput1) {
String value = userInput1.getText();
// ensure entry is a numerical value
try {
amountValue = Double.parseDouble(value);
if (amountValue < 0) {
throw new NumberFormatException();
}
} catch (NumberFormatException ex) {
JOptionPane.showMessageDialog(userInput1,
"Please enter a numeric value to convert.");
}
// sets the userInput value to the unit1
setValues(amountValue);
switch (unit1) {
case "g":
result = String.valueOf(g.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "kg":
result = String.valueOf(kg.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "oz":
result = String.valueOf(ozWeight.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
case "lb":
result = String.valueOf(lb.convertTo(unit2));
userInput2
.setText(df.format(Double.parseDouble(result)));
break;
}//end switch
// if userInput2 triggers ActionEvent we check for unit2
// value and convert to unit1 value
} else if (e.getSource() == userInput2) {
String value = userInput2.getText();
try {
amountValue = Double.parseDouble(value);
if (amountValue < 0) {
throw new NumberFormatException();
}
} catch (NumberFormatException ex) {
JOptionPane
.showMessageDialog(userInput2,
"Please enter a positive numeric value to convert.");
}
// sets the userInput value to the units
setValues(amountValue);
switch (unit2) {
case "g":
result = String.valueOf(g.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "kg":
result = String.valueOf(kg.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "oz":
result = String.valueOf(ozWeight.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
case "lb":
result = String.valueOf(lb.convertTo(unit1));
userInput1
.setText(df.format(Double.parseDouble(result)));
break;
}//end switch
}//end inner if/else
}//end outer if/else for JRadioButton selections
}//end ActionPerformed
}// end UserEntries
private void buildGui() {
JFrame frame = new JFrame("Conversion Calculator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(new GridLayout(4, 1, 0, 5));
frame.getContentPane().add(topPanel);
frame.getContentPane().add(radioPanel);
frame.getContentPane().add(calcInput);
frame.setSize(400, 150);
frame.setResizable(false);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run(){
ConversionLayout run = new ConversionLayout();
run.buildGui();
}
});
}//end main
}// end ConversionLayout
