queue

问题 I'm trying to understand a topic in class about using stacks and queues as a means of programming a calculator. I understand what infix and postfix expression is but how does it make it easier for a program to evaluate an expression and why are queues and stacks ideal in this situation? Thanks 回答1: It makes the order of operations simpler to handle, for example: + * - 4 2 5 3 Can only mean ((4 - 2) * 5) + 3 Which might be more readable for us, but we need to know the order of operations and

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago . I needed to know if laravel 5 queue management system is suitable for big projects (having about 100.000 users). I want to do something like messaging (not spam :) ) users at once each day. Is redis good enough for this job (queuing)? Or it is better to use a lib that is

问题 I'd like to set up propagation in Oracle AQ (11). I'd like to propagate from queue "Q" in queue table "QT" to queue "QD" in queue table "QTD". This is my setup: DECLARE subscriber sys.aq$_agent; BEGIN DBMS_AQADM.CREATE_QUEUE_TABLE(queue_table=>'QT',multiple_consumers=>TRUE,queue_payload_type=>'RAW'); DBMS_AQADM.CREATE_QUEUE_TABLE(queue_table=>'QTD',queue_payload_type=>'RAW'); DBMS_AQADM.CREATE_QUEUE(queue_name => 'Q', queue_table => 'QT'); DBMS_AQADM.CREATE_QUEUE(queue_name => 'QD', queue

问题 I want to use Kafka to "divide the work". I want to publish instances of work to a topic, and run a cloud of identical consumers to process them. As each consumer finishes its work, it will pluck the next work from the topic. Each work should only be processed once by one consumer. Processing work is expensive, so I will need many consumers running on many machines to keep up. I want the number of consumers to grow and shrink as needed (I plan to use Kubernetes for this). I found a pattern

问题 I am working on a practical scenario related with Java;a socket program. The existing system and the expected system are as follows. Existing System - The system checks that a certain condition is satisfied. If so It will create some message to be sent and put it into a queue. The queue processor is a separate thread. It periodically check the queue for existence of items in it. If found any items (messages) it just sends the message to a remote host (hardcoded) and remove the item from queue

问题 I've been reading on the Event-Driven Message Programming Model introduced in April 2013, the OnMessageOptions.ExceptionReceived Event, the built-in RetryPolicy (May 2013, RetryPolicy.Default), The Transient Fault Handling Application Block (2011) which is outdated, and more (see bottom). I've been monitoring the exceptions received through the message pump for transient errors and I get daily MessagingCommunicationExceptions . This article (Updated: September 16, 2014), recommend the

问题 I have an event that is fired when I receive certain notifications. I want to Queue the event so that they aren't all fired at the same time but are Queued up as I receive them and then fired after the previous event completes. I want to know the best way to do this. Edit: Just for anyone in the future, setting up the database Queue driver is very straightforward and simple. You run the php artisan queue:table and change the driver to 'database'. My problem was that my app wasn't recognizing

问题 I'm implementing a queue using a circular array , and I'm kind of stuck in the resize() method implementation (when the array is full). Inside the enqueue() method I check if the size of the array equals it's length, and get if it's full. Now, instead of throwing an exception, I'm trying to resize the array. The thing is, I have two cases to consider front <= rear rear < front Which is the best way to copy the elements of the old array into the new, larger one? I thought it using a for-loop,

问题 I have written a class called QueueManager: class QueueManager { Queue functionsQueue; public bool IsEmpty { get { if (functionsQueue.Count == 0) return true; else return false; } } public QueueManager() { functionsQueue = new Queue(); } public bool Contains(Action action) { if (functionsQueue.Contains(action)) return true; else return false; } public Action Pop() { return functionsQueue.Dequeue() as Action; } public void Add(Action function) { functionsQueue.Enqueue(function); } public void

问题 In my Java application, several threads put data in a queue from which another thread (just one) takes objects and dispatches them. Occasionally, the consuming thread seems to not notice that new items have been added to the queue, as the log messages indicating a poll cease to appear. Log messages from the producing threads indicate that these items do indeed arrive. Googling some taught me that this seems to be known as "missed signal". Since I'm neither wait ing nor using locks, I'm not