Add Queue using ArrayList

Author: bcExpt1123

src/main/java/org/alda/structure/queue/array/QueueArray.java

@@ -0,0 +1,71 @@
+package org.alda.structure.queue.array;
+
+import org.alda.structure.queue.IQueue;
+
+import java.util.ArrayList;
+
+/**
+ * @author bcExpt1123
+ *
+ * Implementation of a generic Queue using an ArrayList.
+ * @param <T>
+ */
+public class QueueArray<T> implements IQueue<T> {
+    /**
+     * Internal storage for the queue elements.
+     */
+    public ArrayList<T> items;
+
+    public QueueArray() {
+        items = new ArrayList<>();
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return
+     */
+    public boolean isEmpty() {
+        return items.isEmpty();
+    }
+
+    /**
+     * {@inheritDoc}
+     * @param item the item to be added.
+     */
+    public void enqueue(T item) {
+        items.add(item);
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return
+     */
+    public T dequeue() {
+        if (items.isEmpty()) {
+            return null;
+        }
+        return items.removeLast();
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return
+     */
+    public T front() {
+        if (items.isEmpty()) {
+            return null;
+        }
+        return items.getFirst();
+    }
+
+    /**
+     * {@inheritDoc}
+     * @return
+     */
+    public T rear(){
+        if (items.isEmpty()) {
+            return null;
+        }
+        return items.getLast();
+    }
+}