The Merore Concurrency Strategy in the Java Class Library
The Merore Concurrency Strategy in the Java Class Library
introduction:
In multi -threaded concurrent programming, it is essential to effectively manage and control the concurrent access to shared resources.The Java class library provides many concurrent tools and classes, which contain some efficient concurrent strategies and models.This article will introduce the efficient concurrent Theore Concurrency strategy in the Java class library, and provide corresponding code examples.
1. Lock mechanism and synchronizer:
The lock mechanism and synchronizer in Java are a basic concurrent control strategy.By using the synchronized keywords or using the Lock interface and its implementation class, we can ensure that multiple threads have a mutually exclusive access to shared resources.The following is a simple example of implementing the keywords using the synchronized keyword:
public class Counter {
private int count = 0;
public synchronized void increment() {
count++;
}
public synchronized void decrement() {
count--;
}
public synchronized int getCount() {
return count;
}
}
2. signal quantity:
Symptoms are a synchronization tool for controlling concurrent access. It can limit the number of threads that access a certain resource at the same time.The SEMAPHORE class is a class that implements the signal mechanism provided in the Java concurrent packet.The following is a simple example:
public class ConnectionPool {
private Semaphore connections;
public ConnectionPool(int size) {
connections = new Semaphore(size);
}
public void getConnection() {
try {
Connections.acquire (); // Get the semaphore, indicate the connection
// Get the operation of connection
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void releaseConnection() {
// Release the operation of the connection
ConnectionS.release (); // Release the signal amount, indicating the release of the connection
}
}
3. Countdown locks:
Countdown locks (Countdownlatch) is a multi -threaded synchronization tool that allows one or more threads to wait for a set of operations to be completed before continuing execution.The COUNTDOWLATCH class controls the number of operations waiting to be completed through a counter.The following is a simple example:
public class DataProcessor {
private CountDownLatch latch;
public DataProcessor(int count) {
latch = new CountDownLatch(count);
}
public void processData() {
try {
// Execute data processing operation
} finally {
LATCH.COUNTDOWN (); // After the operation is completed, the counter is reduced by one
}
}
public void waitForCompletion() {
try {
latch.await (); // Waiting for all operations to complete
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
4. Avoiding dead locks and dead lock detection:
Dead lock is a common problem in multi -threaded concurrent programming.The Java class library provides some strategies and tools to avoid and detect dead locks.For example, by using the `TryLock ()" method instead of the keywords of `synchronized` to avoid dead locks, the ReentrantLock class provides this ability.In addition, the ThreadMXBEAN class provided by Java can be used to detect dead locks in the concurrent program.
public class DeadlockExample {
private final Object lock1 = new Object();
private final Object lock2 = new Object();
public void acquireLocks() {
while (true) {
if (tryAcquireLocks()) {
return;
}
// Waiting for re -try to get the lock
}
}
private boolean tryAcquireLocks() {
if (Thread.holdsLock(lock1) || Thread.holdsLock(lock2)) {
Return false; // already hold locks to avoid dead locks
}
if (Thread.currentThread().getName().equals("Thread1")) {
synchronized (lock1) {
synchronized (lock2) {
// Execute operations
return true;
}
}
} else if (Thread.currentThread().getName().equals("Thread2")) {
synchronized (lock2) {
synchronized (lock1) {
// Execute operations
return true;
}
}
}
return false;
}
}
in conclusion:
The Java class library provides a variety of strategies and tools for achieving high -efficiency concurrency.This article introduces the lock mechanism and synchronizer, semaphore, countdown locks, and common concurrent control strategies such as commonly used with dead lock detection, and provide corresponding Java code examples.In actual development, according to specific business scenarios and needs, you can choose suitable strategies to achieve efficient concurrent programming.
