[도메인주도개발시작하기] Chapter1-도메인 모델 시작

public class Order {
	private OrderState state;
	private ShippingInfo shippingInfo;

	public void changeShippingInfo(ShippingInfo newShippingInfo) {
		if (!state.isShippingChangeable()) {
			throw new IllegalStateException("can't change shipping in " + state);
		}
		this.shippingInfo = newShippingInfo;
	}

	public void changeShipped() {
		// 로직 검사
		this.state = OrderState.SHIPPED;
	}
	...
}

public enum OrderState {
	PAYMENT_WAITING {
		public boolean isShippingChangeable() {
			return true;
		}
	},
	PREPARING {
		public boolean isShippingChangeable() {
			return true;
		}
	},
	SHIPPED, DELIVERING, DELIVERY_COMPLETED;

	public boolean isShippingChangeable() {
		return false;
	}
}

public class Order {
	public void changeShipped() { ... }
	public void changeShippingInfo(ShippingInfo newShipping) { ... }
	public void cancel() { ... }
	public void completePayment() { ... }
}

public class OrderLine {
	private Product product;
	private int price;
	private int quantity;
	private int amount;

	public OrderLine(Product product, int price, int quantity) {
		...
	}

	private int calculateAmounts() {
		return price * quantity;
	}

	public int getAmounts() { ... }
	...
}

public class Order {
	private List<OrderLine> orderLines;
	private int totalAmounts;

	public Order(list<OrderLine> orderLines) {
		setOrderLines(orderLines);
	}

	private void setOrderLines(List<OrderLine> orderLines) { 
			verityAtLeastOneOrMoreOrderLines(orderLines);
			this.orderLines = orderLines;
			calculateTotalAmounts();
	}

	private void verifyAtLeastOneOrMoeOrderLines(List<OrderLine> orderLines) { 
		if (orderLines == null || orderLines.isEmpty()) {
			throw new IllegalArgumentException("no OrderLine");
		}
	 }

	private void calculateTotalAmounts() { 
		this.totalAmounts == new Money(orderLines.stream()
			.mapToInt(x -> x.getAmounts().getValue()).sum());
	}

	...
}

public class ShipingInfo {
	private String receiverName;
	private String receiverPhoneNumber;
	private String shipingAddress1;
	private String shipingAddress2;
	private String shipingZipcode;

	... 생성자, getter
}

public class Order {
    private List<OrderLine> orderLines;
    private ShippingInfo shippingInfo;
    ...

    public Order(List<OrderLine> orderLines, ShippingInfo shippingInfo) {
        setOrderLines(orderLines);
        setShippingInfo(shippingInfo);
    }

    private void setShippingInfo(ShippingInfo shippingInfo) {
    	if(shippingInfo == null) {
    	    throw new IllegalArgumentException("no ShippingInfo");
    	}
    	this.shippingInfo = shippingInfo;
    }
    ...
}

public enum OrderState {
	PAYMENT_WAITING, 
	PREPARING, 
	SHIPPED, 
	DELIVERING, 
	DELIVERY_COMPLETED, 
	CANCELED 
}

public class Order{
	private OrderState state;
	
	public void changeShippingInfo(ShippingInfo newShippingInfo) {
		verifyNotYetShipped();
		setShippingInfo(newShippingInfo);
	}
	public void cancel(){
		verifyNotYetShipped();
		this.state = OrderState.CANCELED;
	}
	private void verifyNotYetShipped(){
		if(state != OrderState.PAYMENT_WAITING && state != OrderState.PREPARING)
			throw new IllegalStateException("already shippped");
	}
	...
}

public class Order {
	public String orderNumber;
	
	@Override
	public boolean equals(Object obj){
		if (this == obj) return true;
		if (obj == null) return false;
		if (obj.getClass() != Order.class) return false;
		Order other = (Order)obj;
		if (this.orderNumber == null) return false;
		return this.orderNumber.equals(other.orderNumber);
	}

	@Override
	public int hashCode(){
		final int prime = 31;
		int result = 1;
		result = prime * result + ((orderNumber == null) ? 0 : orderNumber.hashCode());
		return result;
	}
}

public class ShippingInfo {
	private String receiverName;  // 받는 사람
	private String receiverPhoneNumber; // 받는 사람

	private String shippingAddress1; // 주소
	private String shippingAddress2; // 주소
	private String shippingAddressZipcode; // 주소

	...
}

public class Receiver {
	private String name;
	private String phoneNumber;
	
	public Receiver(String name, String phoneNumber){
		this.name = name;
		this.phoneNumber = phoneNumber;
	}

	public String getName(){
		return name;
	}
	public String getPhoneNumber(){
		return phoneNumber;
	}
}

public class Address{
	private String address1;
	private String address2;
	private String zipcode;
	
	...
}

public class ShippingInfo{
	private Receiver receiver;
	private Address address;
	
	...
}

public class OrderLine {
	private Product product;
	private int price;
	private int quantity;
	private int amounts;
...
}

public class Money{
	private int value;

	public Money(int value){
		this.money = money;
	}

	public int getValue() {
		return this.value;
	}
}

public class OrderLine{
	private Product product;
	private Money price; // Money 타입 덕에 price가 금액을 의미한다는 것을 쉽게 유추할 수 있음
	private int quantity;
	private Money amounts; // Money 타입 덕에 price가 금액을 의미한다는 것을 쉽게 유추할 수 있음
...
}

public class Money{
	private int value;

	public Money(int value){
		this.money = money;
	}

	public int getValue() {
		return this.value;
	}
	
	//새로운 기능 추가 가능
	public Money add(Money money){
		return new Money(this.value + money.value);
	}
	public Money multiply(int multiplier) {
		return new Money(this.value * multiplier);
	}
}

Money price = new Money(1000);
OrderLine line = new OrderLine(product, price, 2) // -> [price=1000, quantity=2, amounts=2000]
price.setValue(2000); // -> [price=2000, quantity=2, amounts=2000]

public class OrderLine {
	...
	private Money price;

	public OrderLine(Product product, Money price, int quantity) {
		this.product = product;
		// Money 가 불변 객체가 아니라면,
		// price 파라미터가 변경될 떄 발생하는 문제를 방지하기 위해
		// 데이터를 복사한 새로운 객체를 생성해야 한다.
		this.price = new Money(price.getValue());
	}
}

public class Receiver{
	private String name;
	private String phoneNumber;
	
	public boolean equals(Object other){
		if (other == null) return false;
		if (this == other) return true;
		if (! (other instanceof Receiver)) return false;
		Receiver that = (Receiver) other;
		
		return this.name.equals(that.name) && this.phoneNumber.equals(that.phoneNumber);
	}
}

public class Order{
	//private String id;
	private OrderNo id;
	...
}

// set 메서드로 데이터를 전달하도록 구현하면
// 처음 Order를 생성하는 시점에 order는 완전하지 않다.
Order order = new  Order();

// set 메서드로 필요한 모든 값을 전달해야 한다. 
order.setOrderLine(lines);
order.setShippingInfo(shipingInfo);

// 주문자(Orderer)를 설정하지 않은 상태에서 주문 완료 처리 -> 문제 발생!!!
order.setState(OrderState.PREPARING);

Order order = new Order(orderer, lines, shippingInfo, OrderState.PREPARING);

public class Order {
    public Order(Orderer orderer, List<OrderLine> orderLines, ShippingInfo shippingInfo, OrderState orderState) {
		setOrderer(orderer);
		setOrderLines(orderLines);
		... // 다른 값 설정
	}

	private void setOrderer(Orderer orderer) {
		if (orderer == null) {
			throw new IllegalArgumentException("no orderer");
		}
		this.orderer = this.orderer;
	}

	private void setOrderLines(List<OrderLine> orderLines) {
		vverifyAtLeastOneOrMoeOrderLines(orderLines);
		this.orderLines = orderLines;
		calculateTotalAmounts();
	}

	private void verifyAtLeastOneOrMoeOrderLines(List<OrderLine> orderLines) { 
		if (orderLines == null || orderLines.isEmpty()) {
			throw new IllegalArgumentException("no OrderLine");
		}
	 }

	private void calculateTotalAmounts() { 
		this.totalAmounts == new Money(orderLines.stream()
			.mapToInt(x -> x.getAmounts().getValue()).sum());
	}
}

public OrderState {
	STEP1, STEP2, STEP3, STEP4, STEP5, STEP6
}

public class Order {
	public void changeShippingInfo(ShippingInfo shippingInfo) {
		verifySetp1OrStep2();
		...
	}
	public void verityStep1OrStep2() { ... }
}