/*
* Copyright 2011, Mysema Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.mysema.query.lucene;
import java.io.IOException;
import java.util.Set;
import javax.annotation.Nullable;
import org.apache.lucene.document.Document;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.ScoreDoc;
import com.google.common.base.Function;
import com.mysema.commons.lang.CloseableIterator;
import com.mysema.query.QueryException;
/**
* ResultIterator is a {@link CloseableIterator} implementation for Lucene query results
*
* @author tiwe
*
* @param <T>
*/
public final class ResultIterator<T> implements CloseableIterator<T> {
private final ScoreDoc[] scoreDocs;
private int cursor;
private final IndexSearcher searcher;
@Nullable
private final Set<String> fieldsToLoad;
private final Function<Document,T> transformer;
public ResultIterator(ScoreDoc[] scoreDocs, int offset, IndexSearcher searcher,
@Nullable Set<String> fieldsToLoad, Function<Document, T> transformer) {
this.scoreDocs = scoreDocs.clone();
this.cursor = offset;
this.searcher = searcher;
this.fieldsToLoad = fieldsToLoad;
this.transformer = transformer;
}
@Override
public boolean hasNext() {
return cursor != scoreDocs.length;
}
@Override
public T next() {
try {
Document document;
if (fieldsToLoad != null) {
document = searcher.doc(scoreDocs[cursor++].doc, fieldsToLoad);
} else {
document = searcher.doc(scoreDocs[cursor++].doc);
}
return transformer.apply(document);
} catch (IOException e) {
throw new QueryException(e);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public void close() {
}
}