task 1.1. first try

project_tasks/src/main/scala/Transaction.scala

@@ -1,5 +1,6 @@
 import exceptions._
 import scala.collection.mutable
+import scala.collection.mutable._
 
 object TransactionStatus extends Enumeration {
   val SUCCESS, PENDING, FAILED = Value
@@ -10,21 +11,21 @@ class TransactionQueue {
     // TODO
     // project task 1.1
     // Add datastructure to contain the transactions
-
+    var queue: Queue[Transaction] = Queue()
     // Remove and return the first element from the queue
-    def pop: Transaction = ???
+    def pop: Transaction = {queue.synchronized(queue.dequeue())}
 
     // Return whether the queue is empty
-    def isEmpty: Boolean = ???
+    def isEmpty: Boolean = {queue.synchronized(queue.isEmpty())}
 
     // Add new element to the back of the queue
-    def push(t: Transaction): Unit = ???
+    def push(t: Transaction): Unit = {queue.synchronized(queue.push(t))}
 
     // Return the first element from the queue without removing it
-    def peek: Transaction = ???
+    def peek: Transaction = {queue.synchronized(queue.front())}
 
     // Return an iterator to allow you to iterate over the queue
-    def iterator: Iterator[Transaction] = ???
+    def iterator: Iterator[Transaction] = {queue.synchronized(queue.iterator())}
 }
 
 class Transaction(val transactionsQueue: TransactionQueue,