RangedSupplierQuery.java

package org.aksw.jena_sparql_api.concept_cache.core;

import java.util.Iterator;
import java.util.stream.Stream;

import org.aksw.commons.collections.utils.StreamUtils;
import org.aksw.jena_sparql_api.core.QueryExecutionFactory;
import org.aksw.jena_sparql_api.util.collection.RangedSupplier;
import org.aksw.jena_sparql_api.utils.IteratorResultSetBinding;
import org.aksw.jena_sparql_api.utils.QueryUtils;
import org.apache.jena.query.Query;
import org.apache.jena.query.QueryExecution;
import org.apache.jena.query.ResultSet;
import org.apache.jena.sparql.algebra.Algebra;
import org.apache.jena.sparql.algebra.Op;
import org.apache.jena.sparql.engine.binding.Binding;

import com.google.common.collect.Range;

public class RangedSupplierQuery
	implements RangedSupplier<Long, Binding>, OpAttribute
{
	protected QueryExecutionFactory qef;
	protected Query query;

	public RangedSupplierQuery(QueryExecutionFactory qef, Query query) {
		super();
		this.qef = qef;
		this.query = query;
	}

	@Override
	public Stream<Binding> apply(Range<Long> range) {
		Query clone = query.cloneQuery();
		QueryUtils.applyRange(clone, range);

		QueryExecution qe = qef.createQueryExecution(clone);
		ResultSet rs = qe.execSelect();


		Iterator<Binding> it = new IteratorResultSetBinding(rs);
		Stream<Binding> result = StreamUtils.stream(it);
		result.onClose(qe::close);

		return result;
//
//		ClosableIterator<Binding> result = new IteratorClosable<>(it, () -> qe.close());
//		return result;
	}

	@Override
	public Op getOp() {
		Op result = Algebra.compile(query);
		return result;
	}

//	@Override
//    public <X> X unwrap(Class<X> clazz, boolean reflexive) {
//    	@SuppressWarnings("unchecked")
//		X result = reflexive && this.getClass().isAssignableFrom(clazz)
//    		? (X)this
//    		: null;
//
//    	return result;
//    }

}