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package de.danoeh.antennapod.discovery;
import android.content.Context;
import android.util.Log;
import android.util.Pair;
import io.reactivex.Single;
import io.reactivex.SingleOnSubscribe;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.schedulers.Schedulers;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
public class CombinedSearcher implements PodcastSearcher {
private static final String TAG = "CombinedSearcher";
private final List<Pair<PodcastSearcher, Float>> searchProviders = new ArrayList<>();
public CombinedSearcher(Context context) {
addProvider(new FyydPodcastSearcher(), 1.f);
addProvider(new ItunesPodcastSearcher(context), 1.f);
//addProvider(new GpodnetPodcastSearcher(), 0.6f);
}
private void addProvider(PodcastSearcher provider, float priority) {
searchProviders.add(new Pair<>(provider, priority));
}
public Single<List<PodcastSearchResult>> search(String query) {
ArrayList<Disposable> disposables = new ArrayList<>();
List<List<PodcastSearchResult>> singleResults = new ArrayList<>(Collections.nCopies(searchProviders.size(), null));
CountDownLatch latch = new CountDownLatch(searchProviders.size());
for (int i = 0; i < searchProviders.size(); i++) {
Pair<PodcastSearcher, Float> searchProviderInfo = searchProviders.get(i);
PodcastSearcher searcher = searchProviderInfo.first;
final int index = i;
disposables.add(searcher.search(query).subscribe(e -> {
singleResults.set(index, e);
latch.countDown();
}, throwable -> {
Log.d(TAG, Log.getStackTraceString(throwable));
latch.countDown();
}
));
}
return Single.create((SingleOnSubscribe<List<PodcastSearchResult>>) subscriber -> {
latch.await();
List<PodcastSearchResult> results = weightSearchResults(singleResults);
subscriber.onSuccess(results);
})
.doOnDispose(() -> {
for (Disposable disposable : disposables) {
disposable.dispose();
}
})
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread());
}
private List<PodcastSearchResult> weightSearchResults(List<List<PodcastSearchResult>> singleResults) {
HashMap<String, Float> resultRanking = new HashMap<>();
HashMap<String, PodcastSearchResult> urlToResult = new HashMap<>();
for (int i = 0; i < singleResults.size(); i++) {
float providerPriority = searchProviders.get(i).second;
List<PodcastSearchResult> providerResults = singleResults.get(i);
if (providerResults == null) {
continue;
}
for (int position = 0; position < providerResults.size(); position++) {
PodcastSearchResult result = providerResults.get(position);
urlToResult.put(result.feedUrl, result);
float ranking = 0;
if (resultRanking.containsKey(result.feedUrl)) {
ranking = resultRanking.get(result.feedUrl);
}
ranking += 1.f / (position + 1.f);
resultRanking.put(result.feedUrl, ranking * providerPriority);
}
}
List<Map.Entry<String, Float>> sortedResults = new ArrayList<>(resultRanking.entrySet());
Collections.sort(sortedResults, (o1, o2) -> Double.compare(o2.getValue(), o1.getValue()));
List<PodcastSearchResult> results = new ArrayList<>();
for (Map.Entry<String, Float> res : sortedResults) {
results.add(urlToResult.get(res.getKey()));
}
return results;
}
}
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