package rpc;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class SyncPromise {
 
    // 用于接收结果
    private RpcResponse rpcResponse;
 
    private final CountDownLatch countDownLatch = new CountDownLatch(1);
    
    // 用于判断是否超时
    private boolean isTimeout = false;
 
    /**
     * 同步等待返回结果
     */
    public RpcResponse get(long timeout, TimeUnit unit) throws InterruptedException {
        // 等待阻塞，超时时间内countDownLatch减到0，将提前唤醒，以此作为是否超时判断
        boolean earlyWakeUp = countDownLatch.await(timeout, unit);
 
        if(earlyWakeUp) {
            // 超时时间内countDownLatch减到0，提前唤醒，说明已有结果
            return rpcResponse;
        } else {
            // 超时时间内countDownLatch没有减到0，自动唤醒，说明超时时间内没有等到结果
            isTimeout = true;
            return null;
        }
    }
 
    public void wake() {
        countDownLatch.countDown();
    }
 
    public RpcResponse getRpcResponse() {
        return rpcResponse;
    }
 
    public void setRpcResponse(RpcResponse rpcResponse) {
        this.rpcResponse = rpcResponse;
    }
 
    public boolean isTimeout() {
        return isTimeout;
    }
 
}