okhttp系列-enqueue过程

本文主要是介绍okhttp系列-enqueue过程，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

1.RealCall.enqueue

final class RealCall implements Call {@Override public void enqueue(Callback responseCallback) {synchronized (this) {if (executed) throw new IllegalStateException("Already Executed");executed = true;}transmitter.callStart();//创建AsyncCall，调用Dispatcher的enqueueclient.dispatcher().enqueue(new AsyncCall(responseCallback));}
}

2.Dispatcher.enqueue

public final class Dispatcher {private final Deque<AsyncCall> readyAsyncCalls = new ArrayDeque<>();void enqueue(AsyncCall call) {synchronized (this) {readyAsyncCalls.add(call); //将call添加到readyAsyncCalls}promoteAndExecute(); //调用执行的方法}
}

3.Dispatcher.promoteAndExecute

public final class Dispatcher {private boolean promoteAndExecute() {assert (!Thread.holdsLock(this));List<AsyncCall> executableCalls = new ArrayList<>();boolean isRunning;synchronized (this) {//遍历readyAsyncCallsfor (Iterator<AsyncCall> i = readyAsyncCalls.iterator(); i.hasNext(); ) {AsyncCall asyncCall = i.next();//如果正在执行的call超过了最大数目64，则不执行if (runningAsyncCalls.size() >= maxRequests) break; // Max capacity.// Host max capacity.//超过了一个主机的最大请求数5if (asyncCall.callsPerHost().get() >= maxRequestsPerHost) continue; //从readyAsyncCalls removei.remove();asyncCall.callsPerHost().incrementAndGet();//添加到executableCallsexecutableCalls.add(asyncCall);//添加到runningAsyncCallsrunningAsyncCalls.add(asyncCall);}isRunning = runningCallsCount() > 0;}for (int i = 0, size = executableCalls.size(); i < size; i++) {AsyncCall asyncCall = executableCalls.get(i);//执行asyncCall.executeOn(executorService());}return isRunning;}
}

4.AsyncCall执行

AsyncCall其实是一个Runnable，所以最终执行的是AsyncCall的execute

final class RealCall implements Call {@Override protected void execute() {try {Response response = getResponseWithInterceptorChain();//触发callback，返回responseresponseCallback.onResponse(RealCall.this, response);} finally {client.dispatcher().finished(this);//从runningAsyncCalls移除}}
}