[Java Design Pattern] - Abstract class

package com.designpattern.learn.section3.chapter4.pratice1;

import java.math.BigDecimal;


public abstract class Bank {

 private BigDecimal amount;

 public Bank(BigDecimal initializeAmount) {
  this.amount = initializeAmount;
 }

 public void deposit(BigDecimal drawAmount) {
  this.amount = this.amount.subtract(drawAmount);
 }

 public void setDeposit(BigDecimal addDeposit) {
  this.amount = this.amount.add(addDeposit);
 }

 public BigDecimal getDeposit() {
  return this.amount;
 }

 public void balanceEnquires() {
  System.out.println("Your deposit: " + this.amount);
 }

 public abstract void checking();

 public abstract void chargeServiceFee(BigDecimal giveInterest);

 public abstract void giveInterest(BigDecimal amount);

}

SavingAccount

package com.designpattern.learn.section3.chapter4.pratice1;

import java.math.BigDecimal;


public class SavingAccount extends Bank {

 /**
  * Constructs a <code>SavingAccount</code>.
  * 
  * @param initializeAmount
  */
 public SavingAccount(BigDecimal initializeAmount) {
  super(initializeAmount);
 }

 /** {@inheritDoc} */
 @Override
 public void checking() {
  System.out.println("Saving Account don't checking fee.");
 }

 /** {@inheritDoc} */
 @Override
 public void chargeServiceFee(BigDecimal giveInterest) {
  System.out.println("Saving Account don't charge Service Fee.");
 }

 /** {@inheritDoc} */
 @Override
 public void giveInterest(BigDecimal amount) {
  System.out.println("You give interest: " + amount);
  setDeposit(getDeposit().add(amount));

  System.out.println("Your deposit change:" + getDeposit());
  chargeServiceFee(amount);
 }

}

CheckingAccount

package com.designpattern.learn.section3.chapter4.pratice1;

import java.math.BigDecimal;

public class CheckingAccount extends Bank {

 // assume 5% fee of depositAmount
 private static final BigDecimal FIVE_SERVICE_FEE = new BigDecimal(0.05);

 /**
  * Constructs a <code>CheckingAccount</code>.
  * 
  * @param initializeAmount
  */
 public CheckingAccount(BigDecimal initializeAmount) {
  super(initializeAmount);
 }

 /** {@inheritDoc} */
 @Override
 public void checking() {
  balanceEnquires();
 }

 /** {@inheritDoc} */
 @Override
 public void chargeServiceFee(BigDecimal giveInterest) {
  // calculator amount of service fee.
  BigDecimal serviceFee = BigDecimal.ZERO;
  serviceFee = giveInterest.multiply(FIVE_SERVICE_FEE);

  // subtract fee into deposit.
  System.out.println("Service Fee: " + serviceFee);
  setDeposit(getDeposit().subtract(serviceFee));

 }

 /** {@inheritDoc} */
 @Override
 public void giveInterest(BigDecimal amount) {
  System.out.println("Your account don't use Give Interest.");
 }

}