package rx;

import io.reactivex.rxjava3.core.Observable;
import io.reactivex.rxjava3.core.Observer;
import io.reactivex.rxjava3.disposables.Disposable;

import java.util.ArrayList;
import java.util.List;

// 模拟本地数据源
class LocalDataSource {
 public Observable<List<String>> getUserInfo() {
 // 模拟本地没有数据
// return Observable.empty();
 List<String> userInfo = new ArrayList<>();
 userInfo.add("Local");
// return Observable.just(userInfo);
 return Observable.empty();
 }

}

// 模拟网络数据源
class RemoteDataSource {
 public Observable<List<String>> getUserInfo() {
 List<String> userInfo = new ArrayList<>();
 userInfo.add("Remote");
 return Observable.just(userInfo);
// return Observable.empty();
 }
}

// 数据仓库类
class UserRepository {
 private final LocalDataSource localDataSource;
 private final RemoteDataSource remoteDataSource;

 public UserRepository(LocalDataSource localDataSource, RemoteDataSource remoteDataSource) {
 this.localDataSource = localDataSource;
 this.remoteDataSource = remoteDataSource;
 }

 public Observable<List<String>> getUserInfo() {
 Observable observable=localDataSource.getUserInfo();
 return localDataSource.getUserInfo()
 .switchIfEmpty(remoteDataSource.getUserInfo());
 }


 public static void main(String[] args) {
 LocalDataSource localDataSource = new LocalDataSource();
 RemoteDataSource remoteDataSource = new RemoteDataSource();
 UserRepository userRepository = new UserRepository(localDataSource, remoteDataSource);
 userRepository.getUserInfo()
 .subscribe(new Observer<List<String>>() {
 @Override
 public void onSubscribe(Disposable d) {
 System.out.println("onSubscribe");
 }

 @Override
 public void onNext(List<String> userInfo) {
 System.out.println("User Info: " + userInfo);
 }

 @Override
 public void onError(Throwable e) {
 System.out.println("onError: " + e.getMessage());
 }

 @Override
 public void onComplete() {
 System.out.println("onComplete");
 }
 });
 }

}