Tempalate Design Pattern

Template Pattern: Whenever we are using abstract classes in Java means we are implementing Template Pattern. Check out the below implementation.


package org.paandav.template;
import java.math.BigDecimal;
public abstract class TaxTemplate {
 public BigDecimal getTotalTax() {
  BigDecimal totalTax = new BigDecimal(0.0);
  totalTax = getFedTax().add(getStateTax());
  return totalTax;
 }
 public abstract BigDecimal getFedTax();
 public abstract BigDecimal getStateTax();
}

package org.paandav.template;
import java.math.BigDecimal;
public class StateOneTax extends TaxTemplate{
 @Override
 public BigDecimal getFedTax() {
  //Tax Calculation Logic
  return new BigDecimal(10.11);
 }
 @Override
 public BigDecimal getStateTax() {
  //Tax Calculation Logic
  return new BigDecimal(12.11);
 }
}

package org.paandav.template;
import java.math.BigDecimal;
public class StateTwoTax extends TaxTemplate{
 @Override
 public BigDecimal getFedTax() {
  //Tax Calculation Logic
  return new BigDecimal(13.00);
 }
 @Override
 public BigDecimal getStateTax() {
  //Tax Calculation Logic
  return new BigDecimal(19.66);
 }
}

package org.paandav.template;
import java.math.BigDecimal;
public class TemplatePatternTest {
 public static void main(String[] args) {
  TaxTemplate stateOneTax = new StateOneTax();
  TaxTemplate stateTwoTax = new StateTwoTax();
  BigDecimal txAmtOne = stateOneTax.getTotalTax();
  BigDecimal txAmtTwo = stateTwoTax.getTotalTax();
  System.out.println("State One Tax = " + txAmtOne);
  System.out.println("State Two Tax = " + txAmtTwo);
 }
}