덱 구현코드 추가

yoonexample/src/main/java/deque/LinkedListDeque.java

@@ -0,0 +1,101 @@
+package deque;
+
+import exception.EmptyDequeException;
+
+public class LinkedListDeque<E> implements Deque<E> {
+
+  private int size;
+  private Node<E> head;
+  private Node<E> tail;
+
+  @Override
+  public int size() {
+    return this.size;
+  }
+
+  @Override
+  public boolean isEmpty() {
+    return this.size == 0;
+  }
+
+  @Override
+  public void addFirst(E data) {
+    Node<E> newNode = new Node<>(data);
+    if (isEmpty()) {
+      this.tail = newNode;
+    } else {
+      this.head.prev = newNode;
+    }
+
+    newNode.next = this.head;
+    this.head = newNode;
+    this.size++;
+  }
+
+  @Override
+  public void addLast(E data) {
+    Node<E> newNode = new Node<>(data);
+    if (isEmpty()) {
+      this.head = newNode;
+    } else {
+      this.tail.next = newNode;
+    }
+
+    newNode.prev = this.tail;
+    this.tail = newNode;
+    this.size++;
+  }
+
+  @Override
+  public E removeFirst() {
+    if (isEmpty()) {
+      throw new EmptyDequeException();
+    }
+
+    E data = this.head.data;
+    this.head = this.head.next;
+    this.size--;
+    return data;
+  }
+
+  @Override
+  public E removeLast() {
+    if (isEmpty()) {
+      throw new EmptyDequeException();
+    }
+
+    E data = this.tail.data;
+    this.tail = this.tail.prev;
+    this.size--;
+    return data;
+  }
+
+  @Override
+  public E getFirst() {
+    if (isEmpty()) {
+      throw new EmptyDequeException();
+    }
+
+    return this.head.data;
+  }
+
+  @Override
+  public E getLast() {
+    if (isEmpty()) {
+      throw new EmptyDequeException();
+    }
+
+    return this.tail.data;
+  }
+
+  private static class Node<T> {
+
+    private T data;
+    private Node<T> next;
+    private Node<T> prev;
+
+    public Node(T data) {
+      this.data = data;
+    }
+  }
+}

yoonexample/src/main/java/exception/EmptyDequeException.java

@@ -0,0 +1,8 @@
+package exception;
+
+public class EmptyDequeException extends RuntimeException {
+
+  public EmptyDequeException() {
+    super("Deque is Emtpy.");
+  }
+}

yoonexample/src/test/java/deque/DequeTest.java

@@ -0,0 +1,136 @@
+package deque;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import exception.EmptyDequeException;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+class DequeTest {
+
+  @Test
+  @DisplayName("덱의_생성_및_초기화_테스트")
+  void 덱의_생성_및_초기화_테스트() {
+    Deque<Integer> deque = new LinkedListDeque<>();
+
+    assertThat(deque).isNotNull();
+    assertThat(deque.size()).isEqualTo(0);
+    assertThat(deque.isEmpty()).isTrue();
+  }
+
+  @Test
+  @DisplayName("덱에_데이터_삽입_테스트")
+  void 덱에_데이터_삽입_테스트() {
+    Deque<Integer> deque = new LinkedListDeque<>();
+
+    deque.addFirst(3);
+    deque.addFirst(2);
+    deque.addFirst(1);
+    deque.addLast(4);
+    deque.addLast(5);
+    deque.addLast(6);
+
+    assertThat(deque).isNotNull();
+    assertThat(deque.size()).isEqualTo(6);
+    assertThat(deque.isEmpty()).isFalse();
+  }
+
+  @Test
+  @DisplayName("덱에_데이터_삽입_앞에서_삭제_테스트")
+  void 덱에_데이터_삽입_앞에서_삭제_테스트() {
+    Deque<Integer> deque = new LinkedListDeque<>();
+
+    deque.addFirst(3);
+    deque.addFirst(2);
+    deque.addFirst(1);
+    deque.addLast(4);
+    deque.addLast(5);
+    deque.addLast(6);
+
+    assertThat(deque).isNotNull();
+    assertThat(deque.size()).isEqualTo(6);
+    assertThat(deque.isEmpty()).isFalse();
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(1);
+    assertThat(deque.size()).isEqualTo(5);
+    assertThat(deque.getFirst()).isEqualTo(2);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(2);
+    assertThat(deque.size()).isEqualTo(4);
+    assertThat(deque.getFirst()).isEqualTo(3);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(3);
+    assertThat(deque.size()).isEqualTo(3);
+    assertThat(deque.getFirst()).isEqualTo(4);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(4);
+    assertThat(deque.size()).isEqualTo(2);
+    assertThat(deque.getFirst()).isEqualTo(5);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(5);
+    assertThat(deque.size()).isEqualTo(1);
+    assertThat(deque.getFirst()).isEqualTo(6);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeFirst()).isEqualTo(6);
+    assertThat(deque.size()).isEqualTo(0);
+    assertThat(deque.isEmpty()).isTrue();
+  }
+
+  @Test
+  @DisplayName("덱에_데이터_삽입_뒤에서_삭제_테스트")
+  void 덱에_데이터_삽입_뒤에서_삭제_테스트() {
+    Deque<Integer> deque = new LinkedListDeque<>();
+
+    deque.addFirst(3);
+    deque.addFirst(2);
+    deque.addFirst(1);
+    deque.addLast(4);
+    deque.addLast(5);
+    deque.addLast(6);
+
+    assertThat(deque).isNotNull();
+    assertThat(deque.size()).isEqualTo(6);
+    assertThat(deque.isEmpty()).isFalse();
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(6);
+    assertThat(deque.removeLast()).isEqualTo(6);
+    assertThat(deque.size()).isEqualTo(5);
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(5);
+    assertThat(deque.removeLast()).isEqualTo(5);
+    assertThat(deque.size()).isEqualTo(4);
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(4);
+    assertThat(deque.removeLast()).isEqualTo(4);
+    assertThat(deque.size()).isEqualTo(3);
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(3);
+    assertThat(deque.removeLast()).isEqualTo(3);
+    assertThat(deque.size()).isEqualTo(2);
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(2);
+    assertThat(deque.removeLast()).isEqualTo(2);
+    assertThat(deque.size()).isEqualTo(1);
+    assertThat(deque.getFirst()).isEqualTo(1);
+    assertThat(deque.getLast()).isEqualTo(1);
+    assertThat(deque.removeLast()).isEqualTo(1);
+    assertThat(deque.size()).isEqualTo(0);
+    assertThat(deque.isEmpty()).isTrue();
+  }
+
+  @Test
+  @DisplayName("덱이_비어있을_때_예외_처리_테스트")
+  void 덱이_비어있을_때_예외_처리_테스트() {
+    Deque<Integer> deque = new LinkedListDeque<>();
+
+    assertThat(deque).isNotNull();
+    assertThat(deque.size()).isEqualTo(0);
+    assertThat(deque.isEmpty()).isTrue();
+    assertThatThrownBy(deque::getFirst).isInstanceOf(EmptyDequeException.class);
+    assertThatThrownBy(deque::removeFirst).isInstanceOf(EmptyDequeException.class);
+    assertThatThrownBy(deque::getLast).isInstanceOf(EmptyDequeException.class);
+    assertThatThrownBy(deque::removeLast).isInstanceOf(EmptyDequeException.class);
+  }
+}