StatefulCalculator.java

StatefulCalculator.java

package org.rondadev.samples;
/**
 * @author rondadev
 * 
 */
public class StatefulCalculator {

  	private StatelessCalculator calculator;
		
		double register = 0;

		public double add(double a) {		
			register = calculator.add(register, a); 
			return register;
		}

		public double subtract(double a) {
			register = calculator.subtract(register, a);
			return register;
		}
		
		public double multiply(double a) {
			register = calculator.multiply(register, a);
			return register;
		}

		public double divide(double a) {		
			register = calculator.divide(register, a);
			return register;
		}
		
		public double display() {		
			return register;
		}

		public void clean() {
			register = 0;		
		}

		public void turnOff() {
			calculator = null;
			System.out.println("[StatefulCalculator] Good bye ! ");
		}
		
		public void turnOn() {
			calculator = new StatelessCalculator();
			System.out.println("[StatefulCalculator] Welcome !");
		}
		
		@SuppressWarnings("unused")
		private void afterCreated() {
			System.out.println("[StatefulCalculator] PostConstruct callback !");		
		}

		@SuppressWarnings("unused")
		private void beforeRemoved() {
			System.out.println("[StatefulCalculator] PreDestroy callback !");		
		}
}