public class TemperatureSensor{
    private double prim_read(){
        if (Math.random()<0.8)
            return -300;
        else
            return Math.random()*70-20; // -20..50
    }
    
    public double readTemperature() throws SensorError{
        double t = prim_read();
        if (t == -300)
            throw new SensorError();
        else
            return t;
    }
        
    class SensorError extends Exception {
    }
    
    public static void monitorTemperature(double low, double high){
        TemperatureSensor ts = new TemperatureSensor();
        int errorReadings = 0;
        for (int i=0;i<300;i++){
            try{
                double t = ts.readTemperature();
                errorReadings = 0;
                if (t<low)
                    System.out.println("Low temperature: " + t);
                if (t>high)
                    System.out.println("High temperature: " + t);
            }catch(SensorError re){
                errorReadings++;
                if (errorReadings>5){
                    System.out.println("Cannot read the temperature");
                    errorReadings = 0;
                }
            }
            try{ Thread.sleep(1);}catch(InterruptedException ie){};
        }
    }

    
    public static void tryMe(){
        monitorTemperature(-15,45);
        System.out.println("------------------");
    }
                
}