In the Javax Enterprise Concurrent API framework, the implementation principles of the Javax Enterprise Concurrent API framework Braries)
In the Java class library, the Javax Enterprise Concurrent API (Java Enterprise Paimori API) framework is a powerful tool for managing and controlling concurrent access.This article will discuss the implementation principle of the framework and provide the necessary Java code examples.
The Javax Enterprise Concurrent API framework aims to provide a reliable and efficient way to manage multi -threaded concurrent access.It can achieve this goal by introducing some key concepts and classes. These concepts and classes can help developers better control interaction between multiple threads.
In this framework, a core concept is lock.Locked to coordinate access between multiple threads to ensure that they do not modify shared resources at the same time.The framework provides a variety of types of locks, including the ReentrantLock (ReentrantLock), the ReentrantReadwritelock, etc. Developers can choose the appropriate lock mechanism according to the needs.
Below is an example of using heavy -duty locks:
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class ConcurrentAccessExample {
private Lock lock = new ReentrantLock();
public void performTask() {
lock.lock();
try {
// The task of executing concurrent access
} finally {
lock.unlock();
}
}
}
In the above example, it can be repeated to control the concurrent access to control the `Performtask ()` method.At the beginning of the method, the thread will try to get the lock. If the lock is occupied by other threads, the current thread will be blocked and waiting.Only when the current thread is successfully obtained can the task of concurrent access can be performed.When the task is executed, the lock is released by calling the `unlock ()` method.
In addition to the lock mechanism, the framework also provides some other useful classes such as Condition and Semaphore.Conditions for communication and waiting between threads can control the execution order of threads.The semaphore is used to control the number of threads that access a certain resource at the same time.
Below is an example of using conditions and semaphores:
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class ConcurrentCommunicationExample {
private Lock lock = new ReentrantLock();
private Condition condition = lock.newCondition();
Private semaphore semaphore = new semaphore (5); // control up to 5 threads at the same time
public void performTask() throws InterruptedException {
lock.lock();
try {
// Preparation before executing the task
condition.await (); // thread waiting conditions are met
// Execute the task
semaphore.acquire (); // Get the semaphore
// Execute the task of accessing shared resources
semaphore.release (); // Release the signal amount
// Clean up after executing the task
} finally {
lock.unlock();
}
}
public void fulfillCondition() {
lock.lock();
try {
condition.signalall (); // Wake up the thread waiting for
} finally {
lock.unlock();
}
}
}
In the above example, the conditions are used to control the obstruction before waiting for the task to meet the specific conditions.When the conditions are met, you wake up the waiting thread by calling the method of calling `signalall ()`.The semaphore is used to control the number of threads that access shared resources at the same time, obtain the semaphore by calling the `Acquire ()` method, and call the `release () method to release the signal volume after the task is executed.
Through the above examples, we can see that the Javax Enterprise Concurrent API framework provides a set of powerful tools and mechanisms to manage and control concurrent access.Developers can choose the right lock, conditions and semaphores, and other related classes according to specific needs.These tools and mechanisms can help developers build efficient and reliable multi -threaded applications.
