Android 源码分析之okhttp3（builder二）

上篇博客简单地介绍了一下builder设计模式，其实也很简单，相信聪明的你能很快理解他的精髓，这篇就来说说okhttp3的设计模式，其实也是builder模式，只不过和alertdialog有点小小的区别，这个区别就是在成员变量位置，ok3没有对成员变量进行封装，而alertdialog将成员变量封装到了一个含有内部类的类中了；

下面先看下ok3的代码：

OkHttpClient okHttpClient = new OkHttpClient.Builder()
.connectTimeout(5, TimeUnit.SECONDS)
.cache(null)
.build();

okHttpClient.newCall(null).enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {

}

@Override
public void onResponse(Call call, Response response) throws IOException {

}
});

1 okhttpclient类的结构

大致分为三部分，成员变量（okhttpclient），内部类（builder）和内部类的的区部变量（builder）三部分；这里我就简单地写下：（看源码不要走进一个误区，非要看懂每一行代码的话那你就比高司令还厉害了，能看懂70%你就了不得了）

public class OkHttpClient{
//变量太多就不全部粘贴出来了
final boolean followRedirects;
final boolean retryOnConnectionFailure;
final int connectTimeout;
final int readTimeout;
final int writeTimeout;
final int pingInterval;

//各种get和set方法，此处省略一万字，你懂得

OkHttpClient(Builder builder) {
this.followRedirects = builder.followRedirects;
this.retryOnConnectionFailure = builder.retryOnConnectionFailure;
this.connectTimeout = builder.connectTimeout;
this.readTimeout = builder.readTimeout;
this.writeTimeout = builder.writeTimeout;
this.pingInterval = builder.pingInterval;
}

//内部类builder
public static final class Builder {

boolean followRedirects;
boolean retryOnConnectionFailure;
int connectTimeout;
int readTimeout;
int writeTimeout;
int pingInterval;

public Builder() {

followSslRedirects = true;
followRedirects = true;
retryOnConnectionFailure = true;
connectTimeout = 10_000;
readTimeout = 10_000;
writeTimeout = 10_000;
pingInterval = 0;
}
public Builder connectionPool(ConnectionPool connectionPool) {
if (connectionPool == null) throw new NullPointerException("connectionPool == null");
this.connectionPool = connectionPool;
return this;
}
//类似方法省略

public OkHttpClient build() {
return new OkHttpClient(this)；//这里直接将builder对象传入构造中，在okhttpclient的构造方法中将builder的变量取出赋值给okhttpclient的成员变量
}
}
}
}

2 newcall方法

/** 源码里面是这样的，
* Prepares the {@code request} to be executed at some point in the future.
*/
@Override public Call newCall(Request request) {
return new RealCall(this, request, false /* for web socket */);
}

//后面调用这个方法，他是而这个方法里面的关键就是AsyncCall，进行请求

@Override public void enqueue(Callback responseCallback) {
synchronized (this) {
if (executed) throw new IllegalStateException("Already Executed");
executed = true;
}
captureCallStackTrace();
client.dispatcher().enqueue(new AsyncCall(responseCallback));
}

我们再来看看Callback是干嘛的：
void onFailure(Call call, IOException e);
void onResponse(Call call, Response response) throws IOException;
原来是一个回调接口；

2 request

Request request = new Request.Builder()
.get()
.build();

也是一个builder模式；