package javaBasic;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
public class JavaAmoticTest {
static abstract class CalculatorBase {
// Creates a new {@code AtomicBoolean} with initial value {@code false}.
AtomicBoolean calledStart = new AtomicBoolean();
AtomicBoolean calledDispose = new AtomicBoolean();
protected void StartCore() {
boolean called = calledStart.getAndSet(true);
// if Called is False, Keeping Running
// if not match, throw java.lang.AssertionError
// and output error message.
assert !called;
try {
Thread.sleep(1000);
System.out.println("Start Finished");
} catch (InterruptedException e) {
}
}
protected void DisposeCore() {
boolean called = calledDispose.getAndSet(true);
assert !called;
try {
Thread.sleep(1000);
System.out.println("Dispose Finished");
} catch (InterruptedException e) {
}
}
public abstract void Start();
public abstract void Dispose();
}
static class CasCalculator extends CalculatorBase {
// Creates a new AtomicInteger with the given initial value.
AtomicInteger state = new AtomicInteger(kNotStarted);
static final int kNotStarted = 0, kStarting = 1, kStarted = 2,
kDisposed = 3;
@Override
public void Start() {
// Atomically sets the value to the given updated value
// if the current value {@code ==} the expected value.
boolean succeed = state.compareAndSet(kNotStarted, kStarting);
if (succeed) {
synchronized (this) {
StartCore();
}
boolean cont = state.compareAndSet(kStarting, kStarted);
if (!cont) {
synchronized (this) {
DisposeCore();
}
}
}
}
@Override
public void Dispose() {
// Atomically sets to the given value and returns the old value.
int orig = state.getAndSet(kDisposed);
if (orig == kStarted) {
synchronized (this) {
DisposeCore();
}
}
}
public static void main(String[] args) throws InterruptedException {
final CasCalculator cal = new CasCalculator();
new Thread() {
@Override
public void run() {
cal.Start();
}
}.start();
new Thread() {
@Override
public void run() {
cal.Start();
}
}.start();
new Thread() {
@Override
public void run() {
cal.Start();
}
}.start();
}
}
}来源：oschina
链接：https://my.oschina.net/u/1412027/blog/196507