RxNonEmptyCursorTransformer.java

/*
 * Copyright (c) 2017 PlanGrid, Inc. All rights reserved.
 */

package com.plangrid.android.loaders.rx;

import android.database.Cursor;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;

import rx.Observable;
import rx.exceptions.Exceptions;

public class RxNonEmptyCursorTransformer extends RxLoaderTransformer<Cursor, CursorLoader> {
    public RxNonEmptyCursorTransformer(LoaderManager loaderManager,
                                       int loaderId,
                                       LoaderStartBehavior loaderStartBehavior,
                                       LoaderResetBehavior loaderResetBehavior) {
        super(loaderManager, loaderId, loaderStartBehavior, loaderResetBehavior);
    }

    @Override public Observable<Cursor> call(Observable<CursorLoader> loaderObservable) {
        return loaderObservable.publish(
                loaderObs -> loaderObs.zipWith(super.call(loaderObs),
                                               (loader, cursor) -> {
                                                   if (cursor == null || cursor.getCount() == 0) {
                                                       throw Exceptions.propagate(new RuntimeException("LOL"));
                                                   }
                                                   return cursor;
                                               }));
    }
}