RMP.java

package com.tevinjeffrey.rmp.common;

import com.tevinjeffrey.rmp.client.RMPClient;
import com.tevinjeffrey.rmp.scraper.RMPScraper;

import rx.Observable;
import rx.Subscriber;
import rx.functions.Func1;
import rx.schedulers.Schedulers;

public class RMP {
    private final RMPClient mRMPClient;
    private final RMPScraper mRMPScraper;

    public static final String RMP_BASE_URL = "http://www.ratemyprofessors.com";

    public RMP(RMPClient mRMPClient, RMPScraper mRMPScraper) {
        this.mRMPClient = mRMPClient;
        this.mRMPScraper = mRMPScraper;
    }

    public Observable<Professor> getProfessor(final Parameter params) {
        Observable<Professor> professorFromClient = mRMPClient.findProfessor(params)
                //Since this is first in the chain, don't try an error just yet.
                .onErrorResumeNext(Observable.<Professor>empty())
                .subscribeOn(Schedulers.io());
        Observable<Professor> professorFromScraper = mRMPScraper.findBestProfessor(params)
                .subscribeOn(Schedulers.io());

        return Observable.concat(professorFromClient, professorFromScraper)
                .takeFirst(new Func1<Professor, Boolean>() {
                    @Override
                    public Boolean call(Professor professor) {
                        return true;
                    }
                })
                .filter(new Func1<Professor, Boolean>() {
                    @Override
                    public Boolean call(Professor professor) {
                        return professor != null;
                    }
                });

    }
}