package com.ctrip.xpipe.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.LockSupport;
/**
* @author wenchao.meng
* <p>
* Jun 29, 2018
*/
public class Gate {
private AtomicBoolean isOpen = new AtomicBoolean(true);
private Queue<Thread> passengers = new ConcurrentLinkedDeque<>();
private String name;
private static final Logger logger = LoggerFactory.getLogger(Gate.class);
public Gate(String name) {
this.name = name;
}
public boolean isOpen() {
return isOpen.get();
}
public void close() {
if (isOpen.compareAndSet(true, false)) {
logger.info("[close][{}]", name);
}
}
public void tryPass() {
if (isOpen.get()) {
return;
}
if (isOpen.get() == false) {
Thread currentThread = Thread.currentThread();
passengers.offer(currentThread);
if (isOpen.get() == true) {
passengers.remove(currentThread);
return;
}
logger.info("[pass][{}]park", name);
LockSupport.park();
logger.info("[pass][{}][park finished]", name);
}
}
public void open() {
if (isOpen.compareAndSet(false, true)) {
logger.info("[open][{}]", name);
makeAllPass();
}
}
private void makeAllPass() {
Thread passenger;
while ((passenger = passengers.poll()) != null) {
logger.info("[makeAllPass][{}], {}", name, passenger);
LockSupport.unpark(passenger);
}
}
@Override
public String toString() {
return String.format("Gate:%s", name);
}
}
