/*
* 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 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.TConsumer3;
import org.apache.jena.atlas.lib.tuple.TFunction3;
import org.apache.jena.atlas.lib.tuple.TupleMap;
import org.apache.jena.graph.Node;
import org.apache.jena.graph.Triple;
import org.apache.jena.sparql.core.mem.FourTupleMap.ThreeTupleMap;
import org.apache.jena.sparql.core.mem.FourTupleMap.TwoTupleMap;
import org.slf4j.Logger;
/**
* A {@link TripleTable} employing persistent maps to index triples in one particular slot order (e.g. SPO, OSP or POS).
*
*/
public class PMapTripleTable extends PMapTupleTable<ThreeTupleMap, Triple, TConsumer3<Node>>implements TripleTable {
/**
* @param order an internal order for this table
*/
public PMapTripleTable(final String order) {
this("SPO", order);
}
/**
* @param canonical the canonical order outside this table
* @param order the internal order for this table
*/
public PMapTripleTable(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 PMapTripleTable(final String tableName, final TupleMap order) {
super(tableName, order);
}
private final static Logger log = getLogger(PMapTripleTable.class);
@Override
protected Logger log() {
return log;
}
@Override
protected ThreeTupleMap initial() {
return new ThreeTupleMap();
}
@Override
public void add(final Triple t) {
map(add()).accept(t);
}
@Override
public void delete(final Triple t) {
map(delete()).accept(t);
}
@Override
public Stream<Triple> find(final Node s, final Node p, final Node o) {
return map(find).apply(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<Triple>) -- but why is that needed?
private TFunction3<Node, Stream<Triple>> find = (first, second, third) -> {
debug("Querying on three-tuple pattern: {} {} {} .", first, second, third);
final ThreeTupleMap threeTuples = local().get();
if (isConcrete(first)) {
debug("Using a specific first slot value.");
return (Stream<Triple>) threeTuples.get(first).map(twoTuples -> {
if (isConcrete(second)) {
debug("Using a specific second slot value.");
return twoTuples.get(second).map(oneTuples -> {
if (isConcrete(third)) {
debug("Using a specific third slot value.");
return oneTuples.contains(third) ? Stream.of(unmap(first, second, third)) : empty();
}
debug("Using a wildcard third slot value.");
return oneTuples.stream().map(slot3 -> unmap(first, second, slot3));
}).orElse(empty());
}
debug("Using wildcard second and third slot values.");
return twoTuples
.flatten((slot2, oneTuples) -> oneTuples.stream().map(slot3 -> unmap(first, slot2, slot3)));
}).orElse(empty());
}
debug("Using a wildcard for all slot values.");
return threeTuples.flatten((slot1, twoTuples) -> twoTuples
.flatten((slot2, oneTuples) -> oneTuples.stream().map(slot3 -> unmap(slot1, slot2, slot3))));
};
@Override
protected TConsumer3<Node> add() {
return (first, second, third) -> {
debug("Adding three-tuple {} {} {}", first, second, third);
final ThreeTupleMap threeTuples = local().get();
TwoTupleMap twoTuples = threeTuples.get(first).orElse(new TwoTupleMap());
PersistentSet<Node> oneTuples = twoTuples.get(second).orElse(PersistentSet.empty());
oneTuples = oneTuples.plus(third);
twoTuples = twoTuples.minus(second).plus(second, oneTuples);
local().set(threeTuples.minus(first).plus(first, twoTuples));
};
}
@Override
protected TConsumer3<Node> delete() {
return (first, second, third) -> {
debug("Deleting three-tuple {} {} {}", first, second, third);
final ThreeTupleMap threeTuples = local().get();
threeTuples.get(first).ifPresent(twoTuples -> twoTuples.get(second).ifPresent(oneTuples -> {
if (oneTuples.contains(third)) {
final TwoTupleMap newTwoTuples = twoTuples.minus(second).plus(second, oneTuples.minus(third));
debug("Setting transactional index to new value.");
local().set(threeTuples.minus(first).plus(first, newTwoTuples));
}
}));
};
}
}