我有这个代码,但我不理解有一个方法调用以增量的零件。
。我的理解(这是正确的吗?)T2将在第35行
上创建一个新线程t3将在第36行中创建一个新线程,然后将其调用。
然后在第41行中,将对T2执行运行方法。在第42行中,将对T3执行运行方法。
package aa.race;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class ThreadDemoCounter implements Runnable
{
int counter;
int alternate;
String name;
public static int numLoops = 4;
public static int numPrints = 1500;
public ThreadDemoCounter(String n)
{
name = n;
counter = 0;
}
// For bonus -- delete method go. Change main to below code:
public static void main(String[] args) throws Exception
{
ThreadDemoCounter c1 = new ThreadDemoCounter("c1");
//Run the multithreaded demo a few times
for (int foo = 0; foo < numLoops; foo++)
{
c1.counter = 0;
Thread t1 = new Thread(c1);
Thread t2 = new Thread(c1);
Thread t3 = new Thread(c1::incrementOnly);
Thread t4 = new Thread(c1::incrementOnly);
t1.start();
t2.start();
t3.start();
t4.start();
t1.join();
t2.join(); //wait for both
t3.join();
t4.join(); //wait for both
System.out.println("c1 = " + c1.counter);
System.out.println("===== end loop =====");
}
}
public void incrementOnly()
{
for (int i =0 ; i < numPrints; i++)
{
incrementCounter();
}
}
public void run()
{
for (int j = 0; j < numPrints; j++)
{
LockFactory.getLock(name).lock();
System.out.println("counter " + name + " = " + getCounter() + " retrieved by thread: " + Thread.currentThread().getName());
incrementCounter();
LockFactory.getLock(name).unlock();
}
System.out.println();
}
public int getCounter()
{
return counter;
} //start at 0
public void incrementCounter()
{
LockFactory.getLock(name).lock();
counter++;
LockFactory.getLock(name).unlock();
}
}
所有4个构造函数都在调用 Thread(Runnable target)
,其中 Runnable
是带有方法void run()
的@FunctionalInterface
。当线程启动时,它将调用Runnable
的run()
方法。
前两个构造函数new Thread(c1)
正在传递ThreadDemoCounter
的实例,因此这两个线程将调用c1
实例的ThreadDemoCounter.run()
方法。
其他两个构造函数正在将A 方法参考传递给c1
的incrementOnly()
方法。这是一种有效的方法,因为它也是一种无验证方法。这两个线程将调用c1
实例的ThreadDemoCounter.incrementOnly()
方法。
总的来说,您将运行4个线程,其中两个执行run()
方法,而其中两个执行incrementOnly()
方法,所有这些方法都在ThreadDemoCounter
的同一实例上,即c1
。
fyi:该代码中没有lambda表达式。方法参考表达式不是lambda表达式。