Understand the basic principles of the low -delayed original concurrent queue in the java class library
The basic principles of the low -delayed original parallel queue in the java class library
Low -Lecent Primitives Concurrent Queue is a data structure provided in the Java library for fast and efficient concurrent data storage and processing.This queue has low delay and can safely share data between multiple threads.This article will introduce the basic principles of low -delayed original concurrent queues, and provide some Java code examples.
Low latency original concurrent queue is mainly implemented based on the Lock-free algorithm.It uses CAS (Compaare-And-SWAP) operation, which is a common atomic operation in concurrent programming.CAS allows us to compare and replace the value of a variable. If the current value is equal to the expectations, the new value is written into the variable.With the help of CAS operations, the low -delayed primitive concurrent queue can achieve concurrent data processing without locking.
First, let's take a look at the data structure of the low -delayed original concurrent queue.It is usually implemented by a ring array. The size of the array is fixed, and it stores the element in a continuous memory block.This data structure can provide fast random access and efficient reuse when removing elements.
The following is an example of a simple low latency original concurrent queue:
import java.util.concurrent.atomic.AtomicReferenceArray;
public class LowLatencyQueue<T> {
private final int capacity;
private final AtomicReferenceArray<T> queue;
private final int mask;
private volatile long head;
private volatile long tail;
public LowLatencyQueue(int capacity) {
this.capacity = findNextPowerOfTwo(capacity);
this.queue = new AtomicReferenceArray<>(this.capacity);
this.mask = this.capacity - 1;
}
public boolean offer(T element) {
long currentTail = tail;
long wrapPoint = currentTail - capacity;
if (head <= wrapPoint) {
return false;
}
int index = (int) currentTail & mask;
queue.set(index, element);
tail++;
return true;
}
public T poll() {
long currentHead = head;
if (currentHead >= tail) {
return null;
}
int index = (int) currentHead & mask;
T element = queue.get(index);
if (element == null) {
return null;
}
queue.set(index, null);
head++;
return element;
}
private int findNextPowerOfTwo(int number) {
number--;
number |= number >> 1;
number |= number >> 2;
number |= number >> 4;
number |= number >> 8;
number |= number >> 16;
return number + 1;
}
}
In the above code, we use the AtomicReferenceArray class to achieve the atomic operation of the array.The offer method is used to add elements to the queue. It first checks whether the queue is full. If it is full, it returns false.Then, it uses CAS operation to put the element into the end of the team and move the tail pointer back.The Poll method is used to obtain elements from the queue. It first checks whether the queue is empty. If it is empty, it returns NULL.Then, it uses CAS operation to remove the team element and move the head pointer back.
The basic principle of low latency primitive concurrent queue is to achieve efficient concurrent data processing through lock -free algorithms and CAS operations.Using this queue can effectively reduce the competition between the low threads and improve the overall performance of the system.This is a very useful data structure in concurrent programming.
To sum up, the low -delayed original concurrent queue is a high -performance data structure in the Java class library. It realizes fast concurrency storage and processing through lock -free algorithm and CAS operation.By using this queue reasonably, we can improve the response speed of the system and maintain data security at the same time.
I hope this article can help you understand the basic principles of low -delayed original concurrent queues and be able to use it flexibly in actual projects.I wish you a happy and efficient programming!
