#Linked queue java plus

This is largely a duplicate of another question. Put probably won't block, because you aren't likely to put two billion objects into the queue. YourObject myObject = queue.take() // Blocks until queue isn't empty.Įverything else is the same. Queue.put(myObject) // Blocks until queue isn't full. If it isn't performant enough (PROFILE!), you can always try something else, and it means you don't have to deal with ANY synchronized stuff: BlockingQueue queue = new LinkedBlockingQueue()

It is still overkill for your application, but odds are it will work fine. Honestly, I'd just use a LinkedBlockingQueue. You will NOT need to do this if you want to block while the queue is empty, because poll() will simply return null while the queue is empty, and poll() is atomic. You CANNOT do this with a ConcurrentLinkedQueue, as all operations are done WITHOUT locking on the instance (using variables).

#Linked queue java plus

Your needs will probably be met by using: Queue queue = Collections.synchronizedList(new LinkedList()) Ī plus of this is that it locks on the instance (queue), so you can synchronize on queue to ensure atomicity of composite operations (as explained by Jared). It's more for when you may have hundreds or even thousands of threads accessing the queue at the same time. If you only have one thread putting stuff into the queue, and another thread taking stuff out of the queue, ConcurrentLinkedQueue is probably overkill. However, LinkedBlockingQueue has a maximum capacity (defaults to Integer.MAX_VALUE, which is over two billion) and thus may or may not be appropriate depending on your circumstances. If you need to block waiting for the queue to not be empty, you probably want to use a LinkedBlockingQueue, and use the take() method. Now, wherever you are creating your producer/consumer objects, pass in the queue so they have somewhere to put their objects (you could use a setter for this, instead, but I prefer to do this kind of thing in a constructor): YourProducer producer = new YourProducer(queue) Īnd: YourConsumer consumer = new YourConsumer(queue) Īnd add stuff to it in your producer: queue.offer(myObject) Īnd take stuff out in your consumer (if the queue is empty, poll() will return null, so check it): YourObject myObject = queue.poll() ConcurrentLinkedQueue does all the locking and other operations you need internally your producer(s) adds data into the queue, and your consumers poll for it.įirst, create your queue: Queue queue = new ConcurrentLinkedQueue()

The QueueNode.No, the methods don't need to be synchronized, and you don't need to define any methods they are already in ConcurrentLinkedQueue, just use them. Copy the QueueNode.java and Queue207.java source files from the following path in MathLAN and import them to the Eclipse project:Ī Queue can be implemented by a singly linked list of QueueNodes. Queue207Implementation.java implements the Queue207 interface.Ĭreate an Eclipse project called queues.Queue207.java defines an interface for queue operations.Creating linked lists and queues in Java are rather similar to the same operations and data structure that you might have enountered in CSC161 and C. In this lab, you will switch to implementing a singly-linked queue using a linked-list to store data. In the last few labs, you have worked at implementing some canonical data structures using an array as the underlying storage structure.