Create java-queue-example

java-queue-example

@@ -0,0 +1,112 @@
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class IterateOverQueueExample {
+    public static void main(String[] args) {
+        Queue<String> waitingQueue = new LinkedList<>();
+
+        waitingQueue.add("John");
+        waitingQueue.add("Brad");
+        waitingQueue.add("Angelina");
+        waitingQueue.add("Julia");
+
+        System.out.println("=== Iterating over a Queue using Java 8 forEach() ===");
+        waitingQueue.forEach(name -> {
+            System.out.println(name);
+        });
+
+        System.out.println("\n=== Iterating over a Queue using iterator() ===");
+        Iterator<String> waitingQueueIterator = waitingQueue.iterator();
+        while (waitingQueueIterator.hasNext()) {
+            String name = waitingQueueIterator.next();
+            System.out.println(name);
+        }
+
+        System.out.println("\n=== Iterating over a Queue using iterator() and Java 8 forEachRemaining() ===");
+        waitingQueueIterator = waitingQueue.iterator();
+        waitingQueueIterator.forEachRemaining(name -> {
+            System.out.println(name);
+        });
+
+        System.out.println("\n=== Iterating over a Queue using simple for-each loop ===");
+        for(String name: waitingQueue) {
+            System.out.println(name);
+        }
+    }
+}
+
+************************************************************************************************************************************************************************
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class QueueExample {
+    public static void main(String[] args) {
+        // Create and initialize a Queue using a LinkedList
+        Queue<String> waitingQueue = new LinkedList<>();
+
+        // Adding new elements to the Queue (The Enqueue operation)
+        waitingQueue.add("Rajeev");
+        waitingQueue.add("Chris");
+        waitingQueue.add("John");
+        waitingQueue.add("Mark");
+        waitingQueue.add("Steven");
+
+        System.out.println("WaitingQueue : " + waitingQueue);
+
+        // Removing an element from the Queue using remove() (The Dequeue operation)
+        // The remove() method throws NoSuchElementException if the Queue is empty
+        String name = waitingQueue.remove();
+        System.out.println("Removed from WaitingQueue : " + name + " | New WaitingQueue : " + waitingQueue);
+
+        // Removing an element from the Queue using poll()
+        // The poll() method is similar to remove() except that it returns null if the Queue is empty.
+        name = waitingQueue.poll();
+        System.out.println("Removed from WaitingQueue : " + name + " | New WaitingQueue : " + waitingQueue);
+    }
+}
+
+***********************************************************************************************************************************************************************
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class QueueSizeSearchFrontExample {
+    public static void main(String[] args) {
+        Queue<String> waitingQueue = new LinkedList<>();
+
+        waitingQueue.add("Jennifer");
+        waitingQueue.add("Angelina");
+        waitingQueue.add("Johnny");
+        waitingQueue.add("Sachin");
+
+        System.out.println("WaitingQueue : " + waitingQueue);
+
+        // Check is a Queue is empty
+        System.out.println("is waitingQueue empty? : " + waitingQueue.isEmpty());
+
+        // Find the size of the Queue
+        System.out.println("Size of waitingQueue : " + waitingQueue.size());
+
+        // Check if the Queue contains an element
+        String name = "Johnny";
+        if(waitingQueue.contains(name)) {
+            System.out.println("WaitingQueue contains " + name);
+        } else {
+            System.out.println("Waiting Queue doesn't contain " + name);
+        }
+
+        // Get the element at the front of the Queue without removing it using element()
+        // The element() method throws NoSuchElementException if the Queue is empty
+        String firstPersonInTheWaitingQueue =  waitingQueue.element();
+        System.out.println("First Person in the Waiting Queue (element()) : " + firstPersonInTheWaitingQueue);
+
+        // Get the element at the front of the Queue without removing it using peek()
+        // The peek() method is similar to element() except that it returns null if the Queue is empty
+        firstPersonInTheWaitingQueue = waitingQueue.peek();
+        System.out.println("First Person in the Waiting Queue : " + firstPersonInTheWaitingQueue);
+
+    }
+}
+