docs: checkstyle for deque

Author: yeoshuheng

src/main/java/dataStructures/queue/Deque/Deque.java

@@ -1,170 +1,178 @@
 package dataStructures.queue;
 
+/**
+ * This class implements a doubly-ended queue, known as a deque.
+ *
+ * @param <T> The type of the element to be stored witin the deque.
+ */
 public class Deque<T> {
 
-    private Node<T> first;
-    private Node<T> last;
-    private int size;
+  private Node<T> first;
 
-    /**
-     * Constructor for empty Deque.
-     */
-    public Deque() {
-        this.size = 0;
-        this.first = this.last = null; // implemented with double-linked list
-    }
+  private Node<T> last;
 
-    /**
-     * Check if deque is empty.
-     *
-     * @return True if empty.
-     */
-    public boolean isEmpty() {
-        return this.size == 0;
-    }
+  private int size;
 
-    /**
-     * Get size of deque.
-     *
-     * @return Size of the deque.
-     */
-    public int getSize() {
-        return this.size;
-    }
+  /**
+   * Constructor for empty Deque.
+   */
+  public Deque() {
+    this.size = 0;
+    this.first = this.last = null; // implemented with double-linked list
+  }
+
+  /**
+   * Check if deque is empty.
+   *
+   * @return True if empty.
+   */
+  public boolean isEmpty() {
+    return this.size == 0;
+  }
 
-    /**
-     * Add element into the back of the deque.
-     *
-     * @param val Element to be added.
-     */
-    public void addElement(T val) {
-        Node<T> newNode = new Node<>(val);
-        if (this.isEmpty()) {
-            this.last = this.first = newNode;
-            size++;
-            return;
-        }
-        Node<T> temp = this.last;
-        temp.next = newNode;
-        newNode.prev = temp;
-        this.last = newNode;
-        this.size++;
+  /**
+   * Get size of deque.
+   *
+   * @return Size of the deque.
+   */
+  public int getSize() {
+    return this.size;
+  }
+
+  /**
+   * Add element into the back of the deque.
+   *
+   * @param val Element to be added.
+   */
+  public void addElement(T val) {
+    Node<T> newNode = new Node<>(val);
+    if (this.isEmpty()) {
+      this.last = this.first = newNode;
+      size++;
+      return;
     }
+    Node<T> temp = this.last;
+    temp.next = newNode;
+    newNode.prev = temp;
+    this.last = newNode;
+    this.size++;
+  }
 
-    /**
-     * Add a element into the front of the deque.
-     * @param val Element to be added.
-     */
-    public void addFirst(T val) {
-        Node<T> newNode = new Node<>(val);
-        if (this.isEmpty()) {
-            this.last = this.first = newNode;
-            size++;
-            return;
-        }
-        Node<T> temp = this.first;
-        temp.prev = newNode;
-        newNode.next = temp;
-        this.first = newNode;
-        size++;
+  /**
+   * Add a element into the front of the deque.
+   *
+   * @param val Element to be added.
+   */
+  public void addFirst(T val) {
+    Node<T> newNode = new Node<>(val);
+    if (this.isEmpty()) {
+      this.last = this.first = newNode;
+      size++;
+      return;
     }
+    Node<T> temp = this.first;
+    temp.prev = newNode;
+    newNode.next = temp;
+    this.first = newNode;
+    size++;
+  }
 
-    /**
-     * Peek the first element of the deque.
-     *
-     * @return The value in the first node of the deque.
-     */
-    public T peekFirst() {
-        if (this.isEmpty()) {
-            return null;
-        }
-        return first.val;
+  /**
+   * Peek the first element of the deque.
+   *
+   * @return The value in the first node of the deque.
+   */
+  public T peekFirst() {
+    if (this.isEmpty()) {
+      return null;
     }
+    return first.val;
+  }
 
-    /**
-     * Peek the last element of the deque.
-     *
-     * @return The value in the last node of the deque.
-     */
-    public T peekLast() {
-        if (this.isEmpty()) {
-            return null;
-        }
-        return last.val;
+  /**
+   * Peek the last element of the deque.
+   *
+   * @return The value in the last node of the deque.
+   */
+  public T peekLast() {
+    if (this.isEmpty()) {
+      return null;
     }
+    return last.val;
+  }
 
-    /**
-     * Removes and retrieves the first element of the deque.
-     *
-     * @return The value in the first node of the deque.
-     */
-    public T pollFirst() {
-        if (this.isEmpty()) {
-            return null;
-        }
-        Node<T> firstNode = this.first;
-        Node<T> newFirstNode = this.first.next;
-        if (newFirstNode != null) {
-            newFirstNode.prev = null;
-        }
-        this.first = newFirstNode;
-        firstNode.next = null;
-        this.size--;
-        return firstNode.val;
+  /**
+   * Removes and retrieves the first element of the deque.
+   *
+   * @return The value in the first node of the deque.
+   */
+  public T pollFirst() {
+    if (this.isEmpty()) {
+      return null;
+    }
+    Node<T> firstNode = this.first;
+    Node<T> newFirstNode = this.first.next;
+    if (newFirstNode != null) {
+      newFirstNode.prev = null;
     }
+    this.first = newFirstNode;
+    firstNode.next = null;
+    this.size--;
+    return firstNode.val;
+  }
 
-    /**
-     * Removes and retrieves the last element of the deque.
-     *
-     * @return The value in the last node of the deque.
-     */
-    public T pollLast() {
-        if (this.isEmpty()) {
-            return null;
-        }
-        Node<T> lastNode = this.last;
-        Node<T> newLastNode = lastNode.prev;
-        if (newLastNode != null) {
-            newLastNode.next = null;
-        }
-        lastNode.prev = null;
-        this.last = newLastNode;
-        this.size--;
-        return lastNode.val;
+  /**
+   * Removes and retrieves the last element of the deque.
+   *
+   * @return The value in the last node of the deque.
+   */
+  public T pollLast() {
+    if (this.isEmpty()) {
+      return null;
+    }
+    Node<T> lastNode = this.last;
+    Node<T> newLastNode = lastNode.prev;
+    if (newLastNode != null) {
+      newLastNode.next = null;
     }
+    lastNode.prev = null;
+    this.last = newLastNode;
+    this.size--;
+    return lastNode.val;
+  }
 
-    /**
-     * Converts Deque into String iteratively.
-     *
-     * @return String representation of elements in the deque.
-     */
-    @Override
-    public String toString() {
-        if (this.isEmpty()) {
-            return "[]";
-        }
-        String ret = "[";
-        Node<T> temp = this.first;
-        while (temp != null) {
-            ret += " " + temp.toString() + " ";
-            temp = temp.next;
-        }
-        return ret + "]";
+  /**
+   * Converts Deque into String iteratively.
+   *
+   * @return String representation of elements in the deque.
+   */
+  @Override
+  public String toString() {
+    if (this.isEmpty()) {
+      return "[]";
+    }
+    String ret = "[";
+    Node<T> temp = this.first;
+    while (temp != null) {
+      ret += " " + temp.toString() + " ";
+      temp = temp.next;
     }
+    return ret + "]";
+  }
 
-    private static class Node<T> {
-        private T val;
-        Node<T> next;
-        Node<T> prev;
+  private static class Node<T> {
+    private T val;
+    Node<T> next;
+    Node<T> prev;
 
-        public Node(T val) {
-            this.val = val;
-            this.next = this.prev = null;
-        }
+    public Node(T val) {
+      this.val = val;
+      this.next = this.prev = null;
+    }
 
-        @Override
-        public String toString() {
-            return this.val.toString();
-        }
+    @Override
+    public String toString() {
+      return this.val.toString();
     }
+  }
 }