PriorityQueue ES6 class syntax

loiane · loiane · commit f6e1f21078b4 · 2016-01-23T19:19:12.000-02:00
diff --git a/chapter04/03-PriorityQueue2.html b/chapter04/03-PriorityQueue2.html
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="UTF-8">
+    <title></title>
+</head>
+<body>
+<script type="text/javascript" src="01-Queue2.js"></script>
+<script type="text/javascript" src="03-PriorityQueue2.js"></script>
+</body>
+</html>
diff --git a/chapter04/03-PriorityQueue2.js b/chapter04/03-PriorityQueue2.js
@@ -0,0 +1,80 @@
+let PriorityQueue2 = (function () {
+
+    class QueueElement {
+        constructor(element, priority){
+            this.element = element;
+            this.priority = priority;
+        }
+    }
+
+    const items = new WeakMap();
+
+    class PriorityQueue2 { //extends Queue2 { //with this approach the private properties are not reachable through inheritance
+
+        constructor () {
+            items.set(this, []);
+        }
+
+        enqueue(element, priority){
+            let queueElement = new QueueElement(element, priority);
+
+            let q = items.get(this);
+
+            let added = false;
+            for (let i=0; i<q.length; i++){
+                if (queueElement.priority < q[i].priority){
+                    q.splice(i,0,queueElement);
+                    added = true;
+                    break;
+                }
+            }
+            if (!added){
+                q.push(queueElement);
+            }
+
+            items.set(this, q);
+        };
+
+        dequeue() {
+            let q = items.get(this);
+            let r = q.shift();
+            items.set(this, q);
+            return r;
+        }
+
+        front() {
+            let q = items.get(this);
+            return q[0];
+        }
+
+        isEmpty(){
+            return items.get(this).length == 0;
+        }
+
+        size(){
+            let q = items.get(this);
+            return q.length;
+        }
+
+        clear(){
+            items.set(this, []);
+        }
+
+        print(){
+            let q = items.get(this);
+            for (let i=0; i<q.length; i++){
+                console.log(`${q[i].element}  - ${q[i].priority}`);
+            }
+        };
+    }
+    return PriorityQueue2;
+})();
+
+
+let priorityQueue = new PriorityQueue2();
+priorityQueue.enqueue("John", 2);
+priorityQueue.enqueue("Jack", 1);
+priorityQueue.enqueue("Camila", 1);
+priorityQueue.enqueue("Maxwell", 2);
+priorityQueue.enqueue("Ana", 3);
+priorityQueue.print();
