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J**A Concurrency Basics: LinkedBlockingDeque Full Analysis! - programmer GoodelinkedblockingqueueClasses are efficient thread-safe queues with a linked list structure, with excellent concurrency performance, flexible blocking and non-blocking operations, and the ability to work with producer and consumer patterns, in additionlinkedblockingqueueIt is also highly scalable and can effectively manage data sharing in a multi-threaded environment, which is a key component to improve the concurrency performance and stability of the program.
If there is a ** shopping platform, this platform needs to process a large number of orders, whenever a user places an order, the system needs to pass the order information to the background handler for further processing, such as inventory management, payment processing, logistics distribution, etc., however, due to the huge number of users, the order volume is also very large, if you directly let the handler immediately process each order, then the system may crash because it can't be processed.
This is and can be usedlinkedblockingqueueTo solve this problem, you can putlinkedblockingqueueImagine a queuing waiting area, whenever a user places an order, the order information is put into this queuing waiting area, and the backend handler can take out the order from this queuing waiting area for processinglinkedblockingqueueIt is a thread-safe queue, so it can guarantee that in a multi-threaded environment, order information will not be duplicated or lost.
Moreover,linkedblockingqueueAnother useful feature is that it can set the waiting time when inserting an element, so if the waiting area is full (reaching the maximum capacity), the new order information needs to wait until there is space to put it, by setting the waiting time, you can control how long the new order information needs to wait, if there is no space beyond this time, then you can throw an exception or do other processing.
linkedblockingqueueIt is mainly used to solve the problem of data sharing and transmission between multiple threads, especially in the producer-consumer scenario. This is a thread-safe blocking queue, and it implementsblockingqueueinterface, and is based on a linked list data structure.
linkedblockingqueueIt is commonly used to solve the following problems:
Thread-safe data sharing: In a multi-threaded environment, data inconsistencies may occur when multiple threads need to access and modify shared datalinkedblockingqueueEnsure data integrity and consistency in concurrent situations through internal locking mechanisms and other synchronization measures. Producer-consumer issues: This is a classic problem in concurrent programming, where the producer generates data and puts it into a buffer, the consumer takes the data out of the buffer, and if the buffer is full, the producer needs to wait; If the buffer is empty, the consumer needs to waitlinkedblockingqueueBlocking is providedput()withtake()method, which allows producers and consumers to automatically block waits when the queue is full or empty, simplifying programming complexity. Flow control: In a high-concurrency system, if the back-end processing speed cannot keep up with the speed at which the front-end generates data, it may cause the system to crash by usinglinkedblockingqueue, a limited queue capacity can be set, and when the queue is full, the producer is blocked, thus achieving control over the flow. DecouplinglinkedblockingqueueIt can also be used to decouple the direct dependencies between producers and consumers, where producers only need to queue data without caring about when or how consumers consume it; Similarly, consumers only need to take data processing out of the queue and don't need to care about who or how the data was produced. This decoupling helps to improve the maintainability and scalability of the system. Use belowlinkedblockingqueueThe class simulates a producer-consumer scenario in which the producer generates integers and puts them into a queue, while the consumer takes the integers from the queue and processes them, as follows:
import j**a.util.concurrent.blockingqueue;
import j**a.util.concurrent.linkedblockingqueue;
A producer class that generates data and puts it into a queue
class producer implements runnable
override
public void run()
catch (interruptedexception e)
The consumer class, which is used to take data from the queue and process it
class consumer implements runnable
override
public void run()
catch (interruptedexception e)
The main class, which is used to demonstrate the use of producers and consumers
public class linkedblockingqueuedemo catch (interruptedexception e)
system.out.println("The procedure is complete");
producerand a consumer classconsumer, they all come truerunnableinterface, so it can run as a thread, and the producer is in itrunmethod to generate integers in a loop and passqueue.put(item)method puts them in a queue where the consumer is locatedrunmethod passedqueue.take()method takes integers from the queue and processes them, if the queue is emptytake()The method blocks until an element is available in the queue.
Inmainmethod, create a capacity of 10linkedblockingqueueinstance, and start a producer thread and a consumer thread respectively, and the program waits for the execution of these two threads to complete and output "Program Execution Completed".
linkedblockingqueueYes, it was realizedblockingqueueinterface, which is a linked list-based, thread-safe blocking queue, is as followslinkedblockingqueueMeaning of some of the main methods in the class:
Constructorlinkedblockingqueue(): Create a one with a default capacity (integer..)max value).linkedblockingqueuelinkedblockingqueue(int capacity): Create a one with the specified capacitylinkedblockingqueue。Add elementsadd(e e): Inserts the specified element into this queue (if it is immediately feasible and does not violate the capacity limit), and returns when successfultrue, if there is currently no space available, it is thrownillegalstateexceptionoffer(e e): Inserts the specified element into this queue (if it is immediately feasible and does not violate the capacity limit), and returns when successfultrueand return if there is currently no space availablefalseput(e e) throws interruptedexception: inserts the specified element into this queue and waits for the necessary space to become available; If space is unavailable, wait until space is available or the thread is interrupted. offer(e e, long timeout, timeunit unit): Inserts the specified element into this queue, waits the specified amount of time to allow other threads to insert or remove the element, or until the thread is interrupted. Remove the elementremove(): Removes and returns the head of this queue, or throws if this queue is emptynosuchelementexceptionpoll(): Removes and returns the head of this queue, or returns if the queue is emptynulltake() throws interruptedexception: Removes and returns to the head of this queue, waiting (if necessary) until the element becomes available or the thread is interrupted. poll(long timeout, timeunit unit): Removes and returns to the head of this queue, waiting for the specified amount of time to allow other threads to insert elements, or until this thread is interrupted or times out. Check the elementselement(): Retrieves but does not remove the head of this queue, and if this queue is empty, throws itnosuchelementexceptionpeek(): Retrieves but does not remove the head of this queue, and returns if the queue is emptynull。Other useful methodssize(): Returns the number of elements in the queue. The accuracy of this method can be affected by concurrent modifications, so it is primarily used for monitoring rather than synchronous control. remainingcapacity(): Returns the number of extra elements that are ideally (without memory and resource constraints) acceptable for this queue. clear(): Removes all elements from the queue. contains(object o): Checks whether the specified element is contained in the queue. drainto(collection c)withdrainto(collection c, int maxelements): Removes and adds elements from the queue to the specified collection until the queue is empty or the specified number of elements are removed. iterator(): Returns an iterator for elements in the queue. Note that the iterators'remove()The method deletes the elements in the queue, but does not automatically adjust the capacity of the queue. toarray(): Returns an array containing all the elements in the queue. 
J**A Concurrency Basics: LinkedBlockingDeque Full Analysis! - programmer GoodelinkedblockingqueueRealizedblockingqueueThe interface stores elements in a linked list structure to ensure thread safety, and its advantage is that it has efficient concurrency performance and scalability, is suitable for producer and consumer modes, and can well handle the problem of data sharing between multiple threads, but its disadvantage is that when the amount of data is very large, it may occupy more memory due to the memory overhead of the linked list structure, in addition, although it provides blocking and non-blocking operations, in high concurrency scenarios, competition between threads may lead to performance degradation.
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