/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.jena.sparql.core.mem;
import static java.util.stream.Stream.empty;
import static java.util.stream.Stream.of;
import static org.slf4j.LoggerFactory.getLogger;
import java.util.stream.Stream;
import org.apache.jena.atlas.lib.persistent.PMap;
import org.apache.jena.atlas.lib.persistent.PersistentSet;
import org.apache.jena.atlas.lib.tuple.TConsumer4;
import org.apache.jena.atlas.lib.tuple.TFunction4;
import org.apache.jena.atlas.lib.tuple.TupleMap;
import org.apache.jena.graph.Node;
import org.apache.jena.sparql.core.Quad;
import org.apache.jena.sparql.core.mem.FourTupleMap.ThreeTupleMap;
import org.apache.jena.sparql.core.mem.FourTupleMap.TwoTupleMap;
import org.slf4j.Logger;
/**
* An implementation of {@link QuadTable} based on the use of nested {@link PMap}s. Intended for high-speed in-memory
* use.
*
*/
public class PMapQuadTable extends PMapTupleTable<FourTupleMap, Quad, TConsumer4<Node>>implements QuadTable {
/**
* @param order an internal order for this table
*/
public PMapQuadTable(final String order) {
this("GSPO", order);
}
/**
* @param canonical the canonical order outside this table
* @param order the internal order for this table
*/
public PMapQuadTable(final String canonical, final String order) {
this(canonical + "->" + order, TupleMap.create(canonical, order));
}
/**
* @param tableName a name for this table
* @param order the order of elements in this table
*/
public PMapQuadTable(final String tableName, final TupleMap order) {
super(tableName, order);
}
private static final Logger log = getLogger(PMapQuadTable.class);
@Override
protected Logger log() {
return log;
}
@Override
protected FourTupleMap initial() {
return new FourTupleMap();
}
@Override
public void add(final Quad q) {
map(add()).accept(q);
}
@Override
public void delete(final Quad q) {
map(delete()).accept(q);
}
@Override
public Stream<Quad> find(Node g, Node s, Node p, Node o) {
return map(find).apply(g, s, p, o);
}
/**
* We descend through the nested {@link PMap}s building up {@link Stream}s of partial tuples from which we develop a
* {@link Stream} of full tuples which is our result. Use {@link Node#ANY} or <code>null</code> for a wildcard.
*/
@SuppressWarnings("unchecked") // Because of (Stream<Quad>) -- but why is that needed?
private TFunction4<Node, Stream<Quad>> find = (first, second, third, fourth) -> {
debug("Querying on four-tuple pattern: {} {} {} {} .", first, second, third, fourth);
final FourTupleMap fourTuples = local().get();
if (isConcrete(first)) {
debug("Using a specific first slot value.");
return (Stream<Quad>) fourTuples.get(first).map(threeTuples -> {
if (isConcrete(second)) {
debug("Using a specific second slot value.");
return threeTuples.get(second).map(twoTuples -> {
if (isConcrete(third)) {
debug("Using a specific third slot value.");
return twoTuples.get(third).map(oneTuples -> {
if (isConcrete(fourth)) {
debug("Using a specific fourth slot value.");
return oneTuples.contains(fourth) ? of(unmap(first, second, third, fourth))
: empty();
}
debug("Using a wildcard fourth slot value.");
return oneTuples.stream().map(slot4 -> unmap(first, second, third, slot4));
}).orElse(empty());
}
debug("Using wildcard third and fourth slot values.");
return twoTuples.flatten((slot3, oneTuples) -> oneTuples.stream()
.map(slot4 -> unmap(first, second, slot3, slot4)));
}).orElse(empty());
}
debug("Using wildcard second, third and fourth slot values.");
return threeTuples.flatten((slot2, twoTuples) -> twoTuples.flatten(
(slot3, oneTuples) -> oneTuples.stream().map(slot4 -> unmap(first, slot2, slot3, slot4))));
}).orElse(empty());
}
debug("Using a wildcard for all slot values.");
return fourTuples.flatten((slot1, threeTuples) -> threeTuples.flatten((slot2, twoTuples) -> twoTuples
.flatten((slot3, oneTuples) -> oneTuples.stream().map(slot4 -> unmap(slot1, slot2, slot3, slot4)))));
};
@Override
protected TConsumer4<Node> add() {
return (first, second, third, fourth) -> {
debug("Adding four-tuple: {} {} {} {} .", first, second, third, fourth);
final FourTupleMap fourTuples = local().get();
ThreeTupleMap threeTuples = fourTuples.get(first).orElse(new ThreeTupleMap());
TwoTupleMap twoTuples = threeTuples.get(second).orElse(new TwoTupleMap());
PersistentSet<Node> oneTuples = twoTuples.get(third).orElse(PersistentSet.empty());
if (!oneTuples.contains(fourth)) oneTuples = oneTuples.plus(fourth);
twoTuples = twoTuples.minus(third).plus(third, oneTuples);
threeTuples = threeTuples.minus(second).plus(second, twoTuples);
debug("Setting transactional index to new value.");
local().set(fourTuples.minus(first).plus(first, threeTuples));
};
}
@Override
protected TConsumer4<Node> delete() {
return (first, second, third, fourth) -> {
debug("Removing four-tuple: {} {} {} {} .", first, second, third, fourth);
final FourTupleMap fourTuples = local().get();
fourTuples.get(first).ifPresent(threeTuples -> threeTuples.get(second)
.ifPresent(twoTuples -> twoTuples.get(third).ifPresent(oneTuples -> {
if (oneTuples.contains(fourth)) {
oneTuples = oneTuples.minus(fourth);
final TwoTupleMap newTwoTuples = twoTuples.minus(third).plus(third, oneTuples);
final ThreeTupleMap newThreeTuples = threeTuples.minus(second).plus(second, newTwoTuples);
debug("Setting transactional index to new value.");
local().set(fourTuples.minus(first).plus(first, newThreeTuples));
}
})));
};
}
}