Chapter 02 를 공부하고 테스트 코드를 추가하라

src/main/java/com/johngrib/objects/_02_movie/AmountDiscountPolicy.java

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+package com.johngrib.objects._02_movie;
+
+/**
+ * 금액 할인 정책.
+ * <p>
+ * 조건을 만족할 경우 일정 금액을 할인해주는 정책.
+ */
+public class AmountDiscountPolicy extends DefaultDiscountPolicy {
+  /** 할인 요금. */
+  private Money discountAmount;
+
+  public AmountDiscountPolicy(Money discountAmount, DiscountCondition... conditions) {
+    super(conditions);
+    this.discountAmount = discountAmount;
+  }
+
+  @Override
+  protected Money getDiscountAmount(Screening screening) {
+    return discountAmount;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/Customer.java

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+package com.johngrib.objects._02_movie;
+
+public class Customer {
+}

src/main/java/com/johngrib/objects/_02_movie/DefaultDiscountPolicy.java

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+package com.johngrib.objects._02_movie;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/** 기본 할인 정책. */
+public abstract class DefaultDiscountPolicy implements DiscountPolicy {
+  /** 하나의 할인 정책은 여러 개의 할인 조건을 포함할 수 있다. */
+  private List<DiscountCondition> conditions = new ArrayList<>();
+
+  public DefaultDiscountPolicy(DiscountCondition... conditions) {
+    this.conditions = Arrays.asList(conditions);
+  }
+
+  /**
+   * 할인 금액을 계산한다.
+   * <p>
+   * Template Method.
+   *
+   * @param screening
+   * @return
+   */
+  @Override
+  public Money calculateDiscountAmount(Screening screening) {
+    for (DiscountCondition each : conditions) {
+      if (each.isSatisfiedBy(screening)) {
+        return getDiscountAmount(screening);
+      }
+    }
+    return Money.ZERO;
+  }
+
+  abstract protected Money getDiscountAmount(Screening screening);
+}

src/main/java/com/johngrib/objects/_02_movie/DiscountCondition.java

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+package com.johngrib.objects._02_movie;
+
+/** 할인 조건. */
+public interface DiscountCondition {
+  /**
+   * 전달된 상영 정보가 할인 조건을 만족시키면 true 를 리턴한다.
+   *
+   * @param screening 상영 정보
+   * @return 할인 조건을 만족했다면 true
+   */
+  boolean isSatisfiedBy(Screening screening);
+}

src/main/java/com/johngrib/objects/_02_movie/DiscountPolicy.java

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+package com.johngrib.objects._02_movie;
+
+/** 할인 정책. */
+public interface DiscountPolicy {
+  /**
+   * 할인 금액을 계산한다.
+   *
+   * @param screening 상영 정보
+   * @return 할인 금액
+   */
+  Money calculateDiscountAmount(Screening screening);
+}

src/main/java/com/johngrib/objects/_02_movie/Money.java

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+package com.johngrib.objects._02_movie;
+
+import lombok.EqualsAndHashCode;
+import lombok.ToString;
+
+import java.math.BigDecimal;
+
+/** 금액. */
+@EqualsAndHashCode
+@ToString
+public class Money {
+  public static final Money ZERO = Money.wons(0);
+
+  private final BigDecimal amount;
+
+  public static Money wons(long amount) {
+    return new Money(BigDecimal.valueOf(amount));
+  }
+
+  public static Money wons(double amount) {
+    return new Money(BigDecimal.valueOf(amount));
+  }
+
+  Money(BigDecimal amount) {
+    this.amount = amount;
+  }
+
+  public Money plus(Money amount) {
+    return new Money(this.amount.add(amount.amount));
+  }
+
+  public Money minus(Money amount) {
+    return new Money(this.amount.subtract(amount.amount));
+  }
+
+  public Money times(double percent) {
+    return new Money(this.amount.multiply(BigDecimal.valueOf(percent)));
+  }
+
+  public boolean isLessThan(Money other) {
+    return amount.compareTo(other.amount) < 0;
+  }
+
+  public boolean isGreaterThanOrEqual(Money other) {
+    return amount.compareTo(other.amount) >= 0;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/Movie.java

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+package com.johngrib.objects._02_movie;
+
+import lombok.Getter;
+
+import java.time.Duration;
+
+/** 영화. */
+public class Movie {
+  private String title;
+  private Duration runningTime;
+  /** 기본 요금. */
+  @Getter
+  private Money fee;
+  /** 할인 정책. */
+  private DiscountPolicy discountPolicy;
+
+  public Movie(String title, Duration runningTime, Money fee, DiscountPolicy discountPolicy) {
+    this.title = title;
+    this.runningTime = runningTime;
+    this.fee = fee;
+    this.discountPolicy = discountPolicy;
+  }
+
+  /**
+   * 할인된 금액을 계산해 리턴한다.
+   *
+   * @param screening 상영 정보
+   * @return 할인된 금액
+   */
+  public Money calculateMovieFee(Screening screening) {
+    if (discountPolicy == null) {
+      return fee;
+    }
+    return fee.minus(discountPolicy.calculateDiscountAmount(screening));
+  }
+
+  /**
+   * 실행 시점에 할인 정책을 변경한다.
+   *
+   * @param discountPolicy 변경할 할인 정책.
+   */
+  public void changeDiscountPolicy(DiscountPolicy discountPolicy) {
+    this.discountPolicy = discountPolicy;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/NoneDiscountPolicy.java

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+package com.johngrib.objects._02_movie;
+
+/**
+ * 할인하지 않는 할인 정책.
+ */
+public class NoneDiscountPolicy implements DiscountPolicy {
+  @Override
+  public Money calculateDiscountAmount(Screening screening) {
+    return Money.ZERO;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/PercentDiscountPolicy.java

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+package com.johngrib.objects._02_movie;
+
+/** 일정 비율 할인 정책. */
+public class PercentDiscountPolicy extends DefaultDiscountPolicy {
+  /** 할인 비율. */
+  private double percent;
+
+  public PercentDiscountPolicy(double percent, DiscountCondition... conditions) {
+    super(conditions);
+    this.percent = percent;
+  }
+
+  @Override
+  protected Money getDiscountAmount(Screening screening) {
+    return screening.getMovieFee().times(percent);
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/PeriodCondition.java

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+package com.johngrib.objects._02_movie;
+
+import java.time.DayOfWeek;
+import java.time.LocalTime;
+
+/** 상영 기간 기준 할인 조건. */
+public class PeriodCondition implements DiscountCondition {
+  /** 요일 */
+  private DayOfWeek dayOfWeek;
+  private LocalTime startTime;
+  private LocalTime endTime;
+
+  public PeriodCondition(DayOfWeek dayOfWeek, LocalTime startTime, LocalTime endTime) {
+    this.dayOfWeek = dayOfWeek;
+    this.startTime = startTime;
+    this.endTime = endTime;
+  }
+
+  /**
+   * 상영 시작 시간이 기간 안에 포함된다면 true 를 리턴한다.
+   *
+   * @param screening 상영 정보
+   * @return 할인 기준을 만족하면 true.
+   */
+  @Override
+  public boolean isSatisfiedBy(Screening screening) {
+    return screening.getStartTime().getDayOfWeek().equals(dayOfWeek)
+            && startTime.compareTo(screening.getStartTime().toLocalTime()) <= 0
+            && endTime.compareTo(screening.getStartTime().toLocalTime()) >= 0;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/README.md

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+# 02. 객체지향 프로그래밍
+
+영화 예매 시스템

src/main/java/com/johngrib/objects/_02_movie/Reservation.java

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+package com.johngrib.objects._02_movie;
+
+/** 예매 정보. */
+public class Reservation {
+  /** 고객. */
+  private Customer customer;
+  /** 상영 정보. */
+  private Screening screening;
+  /** 예매 요금. */
+  private Money fee;
+  /** 인원 수. */
+  private int audienceCount;
+
+  public Reservation(Customer customer, Screening screening, Money fee, int audienceCount) {
+    this.customer = customer;
+    this.screening = screening;
+    this.fee = fee;
+    this.audienceCount = audienceCount;
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/Screening.java

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+package com.johngrib.objects._02_movie;
+
+import java.time.LocalDateTime;
+
+/** 상영. 상영은 사용자들이 예매하는 대상이다. */
+public class Screening {
+  /** 상영할 영화. */
+  private Movie movie;
+  /** 상영 순번. */
+  private int sequence;
+  /** 상영 시작 시간. */
+  private LocalDateTime whenScreened;
+
+  public Screening(Movie movie, int sequence, LocalDateTime whenScreened) {
+    this.movie = movie;
+    this.sequence = sequence;
+    this.whenScreened = whenScreened;
+  }
+
+  /** 상영 시작 시간을 리턴한다. */
+  public LocalDateTime getStartTime() {
+    return whenScreened;
+  }
+
+  /** 순번이 일치하면 true 를 리턴한다. */
+  public boolean isSequence(int sequence) {
+    return this.sequence == sequence;
+  }
+
+  /** 기본 요금을 리턴한다. */
+  public Money getMovieFee() {
+    return movie.getFee();
+  }
+
+  /**
+   * 영화를 예매하고, 예매 정보를 리턴한다.
+   *
+   * @param customer      예매자
+   * @param audienceCount 예매 인원 수
+   * @return 예매 정보
+   */
+  public Reservation reserve(Customer customer, int audienceCount) {
+    return new Reservation(customer, this, calculateFee(audienceCount), audienceCount);
+  }
+
+  /**
+   * 전체 예매 요금을 계산해 리턴한다.
+   *
+   * @param audienceCount 예매 인원 수
+   * @return 예매 요금
+   */
+  private Money calculateFee(int audienceCount) {
+    return movie.calculateMovieFee(this)
+            .times(audienceCount);
+  }
+}

src/main/java/com/johngrib/objects/_02_movie/SequenceCondition.java

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+package com.johngrib.objects._02_movie;
+
+/** 순번 기준 할인 조건. */
+public class SequenceCondition implements DiscountCondition {
+  /** 순번. */
+  private int sequence;
+
+  public SequenceCondition(int sequence) {
+    this.sequence = sequence;
+  }
+
+  @Override
+  public boolean isSatisfiedBy(Screening screening) {
+    return screening.isSequence(sequence);
+  }
+}