今天就跟大家聊聊有关RxJava简单源码的示例分析，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。
demo代码如下
public class ObservableTest {
public static void main(String[] args) {
Observable<Object> observable = Observable.create(new ObservableOnSubscribe<Object>() {
@Override
public void subscribe(ObservableEmitter<Object> observer) throws Exception {
observer.onNext("处理的数字是：" + Math.random() * 100);
observer.onComplete();
}
});
observable.subscribe(new Consumer<Object>() {
@Override
public void accept(Object consumer) throws Exception {
System.out.println("我处理的元素是：" + consumer);
}
});
}
}先看第一行代码
Observable<Object> observable = Observable.create(new ObservableOnSubscribe<Object>() {
@Override
public void subscribe(ObservableEmitter<Object> observer) throws Exception {
observer.onNext("处理的数字是：" + Math.random() * 100);
observer.onComplete();
}
});
//Observable.java
//第1560行
public static <T> Observable<T> create(ObservableOnSubscribe<T> source) {
ObjectHelper.requireNonNull(source, "source is null");
//RxJavaPlugins里有很多方法可以设置，
//有点类似于Spring的ApplicationListener，在对应的生命周期中会被调用
return RxJavaPlugins.onAssembly(new ObservableCreate<T>(source));
}
//RxJavaPlugins.java
//第1031行
public static <T> Observable<T> onAssembly(@NonNull Observable<T> source) {
Function<? super Observable, ? extends Observable> f = onObservableAssembly;
//如果设置了对应的方法，就执行，否则原样返回
if (f != null) {
return apply(f, source);
}
return source;
}可以看到RxJavaPlugins中的方法如果不配置的方法，参数就会原样返回，所以Observable.create最终得到的就是ObservableCreate这个类。
再来看第二行代码
observable.subscribe(new Consumer<Object>() {
@Override
public void accept(Object consumer) throws Exception {
System.out.println("我处理的元素是：" + consumer);
}
});
//Observable.java
//第10869行
public final Disposable subscribe(Consumer<? super T> onNext) {
return subscribe(onNext, Functions.ON_ERROR_MISSING, Functions.EMPTY_ACTION, Functions.emptyConsumer());
}
//Observable.java
//第10958行
public final Disposable subscribe(Consumer<? super T> onNext, Consumer<? super Throwable> onError,
Action onComplete, Consumer<? super Disposable> onSubscribe) {
ObjectHelper.requireNonNull(onNext, "onNext is null");
ObjectHelper.requireNonNull(onError, "onError is null");
ObjectHelper.requireNonNull(onComplete, "onComplete is null");
ObjectHelper.requireNonNull(onSubscribe, "onSubscribe is null");
//这里的onNext就是我们自己写的Consumer类
LambdaObserver<T> ls = new LambdaObserver<T>(onNext, onError, onComplete, onSubscribe);
subscribe(ls);
return ls;
}
//Observable.java
//第10974行
public final void subscribe(Observer<? super T> observer) {
ObjectHelper.requireNonNull(observer, "observer is null");
try {
observer = RxJavaPlugins.onSubscribe(this, observer);
ObjectHelper.requireNonNull(observer, "Plugin returned null Observer");
//还记得我们的observable变量是什么类型么？ObservableCreate！
subscribeActual(observer);
} catch (NullPointerException e) { // NOPMD
throw e;
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
// can't call onError because no way to know if a Disposable has been set or not
// can't call onSubscribe because the call might have set a Subscription already
RxJavaPlugins.onError(e);
NullPointerException npe = new NullPointerException("Actually not, but can't throw other exceptions due to RS");
npe.initCause(e);
throw npe;
}
}
//ObservableCreate.java
//第35行
protected void subscribeActual(Observer<? super T> observer) {
//这里的observer是LambdaObserver
CreateEmitter<T> parent = new CreateEmitter<T>(observer);
observer.onSubscribe(parent);
//省略部分代码
}
//LambdaObserver.java
//第47行
public void onSubscribe(Disposable s) {
//设置AtomicReference的值（LambdaObserver继承了AtomicReference）
//如果之前已经设置过了（AtomicReference的值不为空），则直接返回false
if (DisposableHelper.setOnce(this, s)) {
try {
//在new LambdaObserver()的时候我们设置了onSubscribe = Functions.emptyConsumer()
//所以这里什么都不做
onSubscribe.accept(this);
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
s.dispose();
onError(ex);
}
}
}
//ObservableCreate.java
//第35行
protected void subscribeActual(Observer<? super T> observer) {
//省略部分代码
try {
//还记得source是啥么，就是你在创建Observable的时候new的ObservableOnSubscribe
//于是终于执行到了我们编写的代码中
source.subscribe(parent);
} catch (Throwable ex) {
Exceptions.throwIfFatal(ex);
parent.onError(ex);
}
}
//ObservableOnSubscribe.java
//第6行
public static void main(String[] args) {
Observable<Object> observable = Observable.create(new ObservableOnSubscribe<Object>() {
//开始执行这个方法
//observer是new CreateEmitter<T>(new LambdaObserver());
@Override
public void subscribe(ObservableEmitter<Object> observer) throws Exception {
observer.onNext("处理的数字是：" + Math.random() * 100);
observer.onComplete();
}
});
}
//ObservableCreate$CreateEmitter
//第61行
public void onNext(T t) {
if (t == null) {
onError(new NullPointerException("onNext called with null. Null values are generally not allowed in 2.x operators and sources."));
return;
}
if (!isDisposed()) {
//这里的observer就是LambdaObserver
//t就是《"处理的数字是：" + Math.random() * 100》这段字符串
observer.onNext(t);
}
}
//LambdaObserver.java
//第60行
public void onNext(T t) {
if (!isDisposed()) {
try {
onNext.accept(t);
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
get().dispose();
onError(e);
}
}
}
//ObservableOnSubscribe.java
//第13行
public static void main(String[] args) {
//省略部分代码
observable.subscribe(new Consumer<Object>() {
@Override
public void accept(Object consumer) throws Exception {
System.out.println("我处理的元素是：" + consumer);
}
});
}
//ObservableOnSubscribe.java
//第8行
public static void main(String[] args) {
Observable<Object> observable = Observable.create(new ObservableOnSubscribe<Object>() {
@Override
public void subscribe(ObservableEmitter<Object> observer) throws Exception {
//省略部分代码
observer.onComplete();
}
});
//省略部分代码
}
//ObservableCreate.java
//第95行
public void onComplete() {
if (!isDisposed()) {
try {
observer.onComplete();
} finally {
//取消订阅
dispose();
}
}
}
//LambdaObserver.java
//第86行
public void onComplete() {
if (!isDisposed()) {
lazySet(DisposableHelper.DISPOSED);
try {
//new LambdaObserver的时候设置了为空，所以不执行操作
onComplete.run();
} catch (Throwable e) {
Exceptions.throwIfFatal(e);
RxJavaPlugins.onError(e);
}
}
}至此，调用流程分析完成，可以看到虽然在main方法里我们只写了几行代码，但是内部调用的流程还是很繁杂的
看完上述内容，你们对RxJava简单源码的示例分析有进一步的了解吗？如果还想了解更多知识或者相关内容，请关注天达云行业资讯频道，感谢大家的支持。