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package com.itmill.toolkit.demo;
import com.itmill.toolkit.ui.Button;
import com.itmill.toolkit.ui.GridLayout;
import com.itmill.toolkit.ui.Label;
import com.itmill.toolkit.ui.Window;
// Calculator is created by extending Application-class. Application is
// deployed by adding ApplicationServlet to web.xml and this class as
// "application" parameter to the servlet.
public class Calc extends com.itmill.toolkit.Application {
// Calculation data model is automatically stored in the user session
private double current = 0.0;
private double stored = 0.0;
private char lastOperationRequested = 'C';
// User interface components
private final Label display = new Label("0.0");
private final GridLayout layout = new GridLayout(4, 5);
// Application initialization creates UI and connects it to business logic
@Override
public void init() {
// Place the layout to a floating dialog inside the browser main window
setMainWindow(new Window("Calculator Application"));
getMainWindow().addWindow(new Window("Calc", layout));
// Create and add the components to the layout
layout.addComponent(display, 0, 0, 3, 0);
for (String caption : new String[] { "7", "8", "9", "/", "4", "5", "6",
"*", "1", "2", "3", "-", "0", "=", "C", "+" }) {
Button button = new Button(caption, new Button.ClickListener() {
public void buttonClick(Button.ClickEvent event) {
// On button click, calculate and show the result
display.setValue(calculate(event.getButton()));
}
});
layout.addComponent(button);
}
}
// Calculator "business logic" implemented here to keep the example minimal
private double calculate(Button buttonClicked) {
char requestedOperation = buttonClicked.getCaption().charAt(0);
if ('0' <= requestedOperation && requestedOperation <= '9') {
current = current * 10
+ Double.parseDouble("" + requestedOperation);
return current;
}
switch (lastOperationRequested) {
case '+':
stored += current;
break;
case '-':
stored -= current;
break;
case '/':
stored /= current;
break;
case '*':
stored *= current;
break;
case 'C':
stored = current;
break;
}
lastOperationRequested = requestedOperation;
current = 0.0;
if (requestedOperation == 'C') {
stored = 0.0;
}
return stored;
}
}
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