CavalliumDBEngine/src/main/java/it/cavallium/dbengine/database/luceneutil/ParallelCollectorStreamSearcher.java
2020-12-07 22:15:18 +01:00

68 lines
2.1 KiB
Java

package it.cavallium.dbengine.database.luceneutil;
import it.cavallium.dbengine.database.utils.LuceneParallelStreamCollectorManager;
import java.io.IOException;
import java.util.Set;
import java.util.concurrent.CompletionException;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.function.Consumer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.IndexableField;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.Sort;
import org.jetbrains.annotations.Nullable;
/**
* Unsorted search (low latency and constant memory usage)
*/
public class ParallelCollectorStreamSearcher implements LuceneStreamSearcher {
@Override
public Long streamSearch(IndexSearcher indexSearcher,
Query query,
int limit,
@Nullable Sort luceneSort,
String keyFieldName,
Consumer<String> consumer) throws IOException {
if (luceneSort != null) {
throw new IllegalArgumentException("ParallelCollectorStreamSearcher doesn't support sorted searches");
}
AtomicInteger currentCount = new AtomicInteger();
var result = indexSearcher.search(query, LuceneParallelStreamCollectorManager.fromConsumer(docId -> {
if (currentCount.getAndIncrement() >= limit) {
return false;
} else {
try {
Document d = indexSearcher.doc(docId, Set.of(keyFieldName));
if (d.getFields().isEmpty()) {
System.err.println("The document docId:" + docId + " is empty.");
var realFields = indexSearcher.doc(docId).getFields();
if (!realFields.isEmpty()) {
System.err.println("Present fields:");
for (IndexableField field : realFields) {
System.err.println(" - " + field.name());
}
}
} else {
var field = d.getField(keyFieldName);
if (field == null) {
System.err.println("Can't get key of document docId:" + docId);
} else {
consumer.accept(field.stringValue());
}
}
} catch (IOException e) {
e.printStackTrace();
throw new CompletionException(e);
}
return true;
}
}));
//todo: check the accuracy of our hits counter!
return result.getTotalHitsCount();
}
}