Listen for a constrained property change
import java.beans.PropertyChangeEvent;
import java.beans.PropertyVetoException;
import java.beans.VetoableChangeListener;
import java.beans.VetoableChangeSupport;
public class Main {
private double interest;
private VetoableChangeSupport vcs = new VetoableChangeSupport(this);
public Main() {
vcs.addVetoableChangeListener(new VetoChangeListener());
}
public double getInterest() {
return interest;
}
public void setInterest(double interest) {
try {
vcs.fireVetoableChange("interest", new Double(this.interest), new Double(interest));
this.interest = interest;
} catch (PropertyVetoException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
Main bean = new Main();
bean.setInterest(10.99);
bean.setInterest(15.99);
bean.setInterest(20.99);
}
}
class VetoChangeListener implements VetoableChangeListener {
public void vetoableChange(PropertyChangeEvent evt) throws PropertyVetoException {
String eventName = evt.getPropertyName();
if (eventName.equalsIgnoreCase("interest")) {
double interest = ((Double) evt.getNewValue()).doubleValue();
if (interest > 20.00) {
throw new PropertyVetoException("Interest must be below 20.00", evt);
}
System.out.println("Interest applied = " + interest);
}
}
}
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