【Java】方法接受的参数过多？如何优化？

比如下面这个方法：

public static  Disposable subscribe(final Observable observable, final Consumer onSuccess, final Consumer onError, final boolean showLoading) {
    return observable.compose(handleErrors()).subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .doOnSubscribe(disposable1 -> {
                if (showLoading) {
                    DialogUtil.showLoading(AppUtil.getActivity());
                }
            })
            .doFinally(() -> {
                if (showLoading) {
                    DialogUtil.stopLoading(AppUtil.getActivity());
                }
            })
            .subscribe(onSuccess, onError);
}

这是android app项目中的一个方法，且不管它是做什么的，我们来看下如何优化。

我们可以使用Builder模式来优化，代码如下：

public class RxSubscriberBuilder {
    private final Observable observable;
    private Consumer onSuccess;
    private Consumer onError;
    private boolean showLoading = false;

    private RxSubscriberBuilder(Observable observable) {
        this.observable = observable;
    }

    public static   RxSubscriberBuilder create(Observable observable) {
        return new RxSubscriberBuilder(observable);
    }

    public RxSubscriberBuilder onSuccess(Consumer onSuccess) {
        this.onSuccess = onSuccess;
        return this;
    }

    public RxSubscriberBuilder onError(Consumer onError) {
        this.onError = onError;
        return this;
    }

    public RxSubscriberBuilder showLoading(boolean showLoading) {
        this.showLoading = showLoading;
        return this;
    }

    public Disposable subscribe() {
        return observable.compose(handleErrors()).subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .doOnSubscribe(disposable1 -> {
                    if (showLoading) {
                        DialogUtil.showLoading(AppUtil.getActivity());
                    }
                })
                .doFinally(() -> {
                    if (showLoading) {
                        DialogUtil.stopLoading(AppUtil.getActivity());
                    }
                })
                .subscribe(onSuccess, onError);
    }

    private ObservableTransformer handleErrors() {
        return upstream -> upstream.onErrorResumeNext((Throwable throwable) -> {
            if (throwable instanceof AuthException) {
                ToastUtils.show("登录失效");
            }
            return Observable.error(throwable);
        });
    }
}

 使用：

RxSubscriberBuilder.create(api.getUser().toObservable())
        .onSuccess(userDTO -> {})
        .onError(throwable -> {})
        .showLoading(true)
        .subscribe();

我个人感觉方便了很多，比如我可能不需要传入onerror，使用建造者模式后可以选择不调用onerror即可，但如果是写成工具类，那就需要进行方法重载了 。一个简单的例子，希望对你有启发。

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