Update GenericArrayListQueue.java

Documentations added

DataStructures/Queues/GenericArrayListQueue.java

@@ -2,29 +2,68 @@ package DataStructures.Queues;
 
 import java.util.ArrayList;
 
+/**
+ * This class implements a GenericArrayListQueue.
+ * <p>
+ * A GenericArrayListQueue data structure functions the same as any specific-typed queue.
+ * The GenericArrayListQueue holds elemets of types to-be-specified at runtime.
+ * The elements that are added first are the first to be removed (FIFO)
+ * New elements are added to the back/rear of the queue.
+ *
+ */
 public class GenericArrayListQueue<T> {
+    /**
+     * The generic ArrayList for the queue
+     * T is the generic element
+     */
     ArrayList<T> _queue = new ArrayList<T>();
 
+    /**
+     * Checks if the queue has elements (not empty)
+     *
+     * @return True if the queue has elements. False otherwise.
+     */
     private boolean hasElements() {
         return !_queue.isEmpty();
     }
 
+    /**
+     * Checks what's at the front of the queue
+     *
+     * @return If queue is not empty, element at the front of the queue. Otherwise, null
+     */
     public T peek() {
         T result = null;
         if(this.hasElements()) { result = _queue.get(0); }
         return result;
     }
 
+    /**
+     * Inserts an element of type T to the queue.
+     *
+     * @param element of type T to be added
+     * @return True if the element was added successfully
+     */
     public boolean add(T element) {
         return _queue.add(element);
     }
 
+    /**
+     * Retrieve what's at the front of the queue
+     *
+     * @return If queue is not empty, element retrieved. Otherwise, null
+     */
     public T poll() {
         T result = null;
         if(this.hasElements()) { result = _queue.remove(0); }
         return result;
     }
 
+    /**
+     * Main method
+     *
+     * @param args Command line arguments
+     */
     public static void main(String[] args) {
         GenericArrayListQueue<Integer> queue = new GenericArrayListQueue<Integer>();
         System.out.println("Running...");