/*
* 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.tinkerpop.gremlin.structure.util.star;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.tinkerpop.gremlin.process.computer.GraphFilter;
import org.apache.tinkerpop.gremlin.structure.Direction;
import org.apache.tinkerpop.gremlin.structure.Edge;
import org.apache.tinkerpop.gremlin.structure.T;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;
import org.apache.tinkerpop.gremlin.structure.io.gryo.kryoshim.InputShim;
import org.apache.tinkerpop.gremlin.structure.io.gryo.kryoshim.KryoShim;
import org.apache.tinkerpop.gremlin.structure.io.gryo.kryoshim.OutputShim;
import org.apache.tinkerpop.gremlin.structure.io.gryo.kryoshim.SerializerShim;
/**
* Kryo serializer for {@link StarGraph}. Implements an internal versioning capability for backward compatibility.
* The single byte at the front of the serialization stream denotes the version. That version can be used to choose
* the correct deserialization mechanism. The limitation is that this versioning won't help with backward
* compatibility for custom serializers from providers. Providers should be encouraged to write their serializers
* with backward compatibility in mind.
*
* @author Marko A. Rodriguez (http://markorodriguez.com)
* @author Stephen Mallette (http://stephen.genoprime.com)
*/
public class StarGraphSerializer implements SerializerShim<StarGraph> {
private final Direction edgeDirectionToSerialize;
private GraphFilter graphFilter;
private final static byte VERSION_1 = Byte.MIN_VALUE;
public StarGraphSerializer(final Direction edgeDirectionToSerialize, final GraphFilter graphFilter) {
this.edgeDirectionToSerialize = edgeDirectionToSerialize;
this.graphFilter = graphFilter;
}
@Override
public <O extends OutputShim> void write(final KryoShim<?, O> kryo, final O output, final StarGraph starGraph) {
output.writeByte(VERSION_1);
kryo.writeObjectOrNull(output, starGraph.edgeProperties, HashMap.class);
kryo.writeObjectOrNull(output, starGraph.metaProperties, HashMap.class);
kryo.writeClassAndObject(output, starGraph.starVertex.id);
kryo.writeObject(output, starGraph.starVertex.label);
writeEdges(kryo, output, starGraph, Direction.IN);
writeEdges(kryo, output, starGraph, Direction.OUT);
kryo.writeObject(output, null != starGraph.starVertex.vertexProperties);
if (null != starGraph.starVertex.vertexProperties) {
kryo.writeObject(output, starGraph.starVertex.vertexProperties.size());
for (final Map.Entry<String, List<VertexProperty>> vertexProperties : starGraph.starVertex.vertexProperties.entrySet()) {
kryo.writeObject(output, vertexProperties.getKey());
kryo.writeObject(output, vertexProperties.getValue().size());
for (final VertexProperty vertexProperty : vertexProperties.getValue()) {
kryo.writeClassAndObject(output, vertexProperty.id());
kryo.writeClassAndObject(output, vertexProperty.value());
}
}
}
}
/**
* If the returned {@link StarGraph} is null, that means that the {@link GraphFilter} filtered the vertex.
*/
@Override
public <I extends InputShim> StarGraph read(final KryoShim<I, ?> kryo, final I input, final Class<StarGraph> clazz) {
final StarGraph starGraph = StarGraph.open();
input.readByte(); // version field ignored for now - for future use with backward compatibility
starGraph.edgeProperties = kryo.readObjectOrNull(input, HashMap.class);
starGraph.metaProperties = kryo.readObjectOrNull(input, HashMap.class);
starGraph.addVertex(T.id, kryo.readClassAndObject(input), T.label, kryo.readObject(input, String.class));
readEdges(kryo, input, starGraph, Direction.IN);
readEdges(kryo, input, starGraph, Direction.OUT);
if (kryo.readObject(input, Boolean.class)) {
final int numberOfUniqueKeys = kryo.readObject(input, Integer.class);
for (int i = 0; i < numberOfUniqueKeys; i++) {
final String vertexPropertyKey = kryo.readObject(input, String.class);
final int numberOfVertexPropertiesWithKey = kryo.readObject(input, Integer.class);
for (int j = 0; j < numberOfVertexPropertiesWithKey; j++) {
final Object id = kryo.readClassAndObject(input);
final Object value = kryo.readClassAndObject(input);
starGraph.starVertex.property(VertexProperty.Cardinality.list, vertexPropertyKey, value, T.id, id);
}
}
}
return this.graphFilter.hasFilter() ? starGraph.applyGraphFilter(this.graphFilter).orElse(null) : starGraph;
}
private <O extends OutputShim> void writeEdges(final KryoShim<?, O> kryo, final O output, final StarGraph starGraph, final Direction direction) {
// only write edges if there are some AND if the user requested them to be serialized AND if they match
// the direction being serialized by the format
final Map<String, List<Edge>> starEdges = direction.equals(Direction.OUT) ? starGraph.starVertex.outEdges : starGraph.starVertex.inEdges;
final boolean writeEdges = null != starEdges && edgeDirectionToSerialize != null
&& (edgeDirectionToSerialize == direction || edgeDirectionToSerialize == Direction.BOTH);
kryo.writeObject(output, writeEdges);
if (writeEdges) {
kryo.writeObject(output, starEdges.size());
for (final Map.Entry<String, List<Edge>> edges : starEdges.entrySet()) {
kryo.writeObject(output, edges.getKey());
kryo.writeObject(output, edges.getValue().size());
for (final Edge edge : edges.getValue()) {
kryo.writeClassAndObject(output, edge.id());
kryo.writeClassAndObject(output, direction.equals(Direction.OUT) ? edge.inVertex().id() : edge.outVertex().id());
}
}
}
}
private <I extends InputShim> void readEdges(final KryoShim<I, ?> kryo, final I input, final StarGraph starGraph, final Direction direction) {
if (kryo.readObject(input, Boolean.class)) {
final int numberOfUniqueLabels = kryo.readObject(input, Integer.class);
for (int i = 0; i < numberOfUniqueLabels; i++) {
final String edgeLabel = kryo.readObject(input, String.class);
final int numberOfEdgesWithLabel = kryo.readObject(input, Integer.class);
for (int j = 0; j < numberOfEdgesWithLabel; j++) {
final Object edgeId = kryo.readClassAndObject(input);
final Object adjacentVertexId = kryo.readClassAndObject(input);
if (this.graphFilter.checkEdgeLegality(direction, edgeLabel).positive()) {
if (direction.equals(Direction.OUT))
starGraph.starVertex.addOutEdge(edgeLabel, starGraph.addVertex(T.id, adjacentVertexId), T.id, edgeId);
else
starGraph.starVertex.addInEdge(edgeLabel, starGraph.addVertex(T.id, adjacentVertexId), T.id, edgeId);
} else if (null != starGraph.edgeProperties) {
starGraph.edgeProperties.remove(edgeId);
}
}
}
}
}
}