/*
* 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.io.gryo;
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.Graph;
import org.apache.tinkerpop.gremlin.structure.Property;
import org.apache.tinkerpop.gremlin.structure.T;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;
import org.apache.tinkerpop.gremlin.structure.io.GraphReader;
import org.apache.tinkerpop.gremlin.structure.io.GraphWriter;
import org.apache.tinkerpop.gremlin.structure.io.Mapper;
import org.apache.tinkerpop.gremlin.structure.util.Attachable;
import org.apache.tinkerpop.gremlin.structure.util.Host;
import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedEdge;
import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedProperty;
import org.apache.tinkerpop.gremlin.structure.util.detached.DetachedVertexProperty;
import org.apache.tinkerpop.gremlin.structure.util.star.StarGraph;
import org.apache.tinkerpop.gremlin.structure.util.star.StarGraphGryoSerializer;
import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;
import org.apache.tinkerpop.shaded.kryo.Kryo;
import org.apache.tinkerpop.shaded.kryo.io.Input;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Function;
/**
* The {@link GraphReader} for the Gremlin Structure serialization format based on Kryo. The format is meant to be
* non-lossy in terms of Gremlin Structure to Gremlin Structure migrations (assuming both structure implementations
* support the same graph features).
* <p/>
* This implementation is not thread-safe. Have one {@code GryoReader} instance per thread.
*
* @author Stephen Mallette (http://stephen.genoprime.com)
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class GryoReader implements GraphReader {
private final Kryo kryo;
private final Map<GraphFilter, StarGraphGryoSerializer> graphFilterCache = new HashMap<>();
private final long batchSize;
private GryoReader(final long batchSize, final Mapper<Kryo> gryoMapper) {
this.kryo = gryoMapper.createMapper();
this.batchSize = batchSize;
}
/**
* Read data into a {@link Graph} from output generated by any of the {@link GryoWriter} {@code writeVertex} or
* {@code writeVertices} methods or by {@link GryoWriter#writeGraph(OutputStream, Graph)}.
*
* @param inputStream a stream containing an entire graph of vertices and edges as defined by the accompanying
* {@link GraphWriter#writeGraph(OutputStream, Graph)}.
* @param graphToWriteTo the graph to write to when reading from the stream.
* @throws IOException
*/
@Override
public void readGraph(final InputStream inputStream, final Graph graphToWriteTo) throws IOException {
// dual pass - create all vertices and store to cache the ids. then create edges. as long as we don't
// have vertex labels in the output we can't do this single pass
final Map<StarGraph.StarVertex, Vertex> cache = new HashMap<>();
final AtomicLong counter = new AtomicLong(0);
final Graph.Features.EdgeFeatures edgeFeatures = graphToWriteTo.features().edge();
final boolean supportsTx = graphToWriteTo.features().graph().supportsTransactions();
IteratorUtils.iterate(new VertexInputIterator(new Input(inputStream), attachable -> {
final Vertex v = cache.put((StarGraph.StarVertex) attachable.get(), attachable.attach(Attachable.Method.create(graphToWriteTo)));
if (supportsTx && counter.incrementAndGet() % batchSize == 0)
graphToWriteTo.tx().commit();
return v;
}, null, null));
cache.entrySet().forEach(kv -> kv.getKey().edges(Direction.IN).forEachRemaining(e -> {
// can't use a standard Attachable attach method here because we have to use the cache for those
// graphs that don't support userSuppliedIds on edges. note that outVertex/inVertex methods return
// StarAdjacentVertex whose equality should match StarVertex.
final Vertex cachedOutV = cache.get(e.outVertex());
final Vertex cachedInV = cache.get(e.inVertex());
if (null == cachedOutV) throw new IllegalStateException(String.format("Could not find outV with id [%s] to create edge with id [%s]", e.outVertex().id(), e.id()));
if (null == cachedInV) throw new IllegalStateException(String.format("Could not find inV with id [%s] to create edge with id [%s]", e.inVertex().id(), e.id()));
final Edge newEdge = edgeFeatures.willAllowId(e.id()) ? cachedOutV.addEdge(e.label(), cachedInV, T.id, e.id()) : cachedOutV.addEdge(e.label(), cachedInV);
e.properties().forEachRemaining(p -> newEdge.property(p.key(), p.value()));
if (supportsTx && counter.incrementAndGet() % batchSize == 0)
graphToWriteTo.tx().commit();
}));
if (supportsTx) graphToWriteTo.tx().commit();
}
@Override
public Optional<Vertex> readVertex(final InputStream inputStream, final GraphFilter graphFilter) throws IOException {
StarGraphGryoSerializer serializer = this.graphFilterCache.get(graphFilter);
if (null == serializer) {
serializer = StarGraphGryoSerializer.withGraphFilter(graphFilter);
this.graphFilterCache.put(graphFilter, serializer);
}
final Input input = new Input(inputStream);
this.readHeader(input);
final StarGraph starGraph = this.kryo.readObject(input, StarGraph.class, serializer);
// read the terminator
this.kryo.readClassAndObject(input);
return Optional.ofNullable(starGraph == null ? null : starGraph.getStarVertex());
}
/**
* Read {@link Vertex} objects from output generated by any of the {@link GryoWriter} {@code writeVertex} or
* {@code writeVertices} methods or by {@link GryoWriter#writeGraph(OutputStream, Graph)}.
*
* @param inputStream a stream containing at least one {@link Vertex} as defined by the accompanying
* {@link GraphWriter#writeVertices(OutputStream, Iterator, Direction)} or
* {@link GraphWriter#writeVertices(OutputStream, Iterator)} methods.
* @param vertexAttachMethod a function that creates re-attaches a {@link Vertex} to a {@link Host} object.
* @param edgeAttachMethod a function that creates re-attaches a {@link Edge} to a {@link Host} object.
* @param attachEdgesOfThisDirection only edges of this direction are passed to the {@code edgeMaker}.
*/
@Override
public Iterator<Vertex> readVertices(final InputStream inputStream,
final Function<Attachable<Vertex>, Vertex> vertexAttachMethod,
final Function<Attachable<Edge>, Edge> edgeAttachMethod,
final Direction attachEdgesOfThisDirection) throws IOException {
return new VertexInputIterator(new Input(inputStream), vertexAttachMethod, attachEdgesOfThisDirection, edgeAttachMethod);
}
/**
* Read a {@link Vertex} from output generated by any of the {@link GryoWriter} {@code writeVertex} or
* {@code writeVertices} methods or by {@link GryoWriter#writeGraph(OutputStream, Graph)}.
*
* @param inputStream a stream containing at least a single vertex as defined by the accompanying
* {@link GraphWriter#writeVertex(OutputStream, Vertex)}.
* @param vertexAttachMethod a function that creates re-attaches a {@link Vertex} to a {@link Host} object.
*/
@Override
public Vertex readVertex(final InputStream inputStream, final Function<Attachable<Vertex>, Vertex> vertexAttachMethod) throws IOException {
return readVertex(inputStream, vertexAttachMethod, null, null);
}
/**
* Read a {@link Vertex} from output generated by any of the {@link GryoWriter} {@code writeVertex} or
* {@code writeVertices} methods or by {@link GryoWriter#writeGraph(OutputStream, Graph)}.
*
* @param inputStream a stream containing at least one {@link Vertex} as defined by the accompanying
* {@link GraphWriter#writeVertices(OutputStream, Iterator, Direction)} method.
* @param vertexAttachMethod a function that creates re-attaches a {@link Vertex} to a {@link Host} object.
* @param edgeAttachMethod a function that creates re-attaches a {@link Edge} to a {@link Host} object.
* @param attachEdgesOfThisDirection only edges of this direction are passed to the {@code edgeMaker}.
*/
@Override
public Vertex readVertex(final InputStream inputStream,
final Function<Attachable<Vertex>, Vertex> vertexAttachMethod,
final Function<Attachable<Edge>, Edge> edgeAttachMethod,
final Direction attachEdgesOfThisDirection) throws IOException {
final Input input = new Input(inputStream);
return readVertexInternal(vertexAttachMethod, edgeAttachMethod, attachEdgesOfThisDirection, input);
}
/**
* Read an {@link Edge} from output generated by {@link GryoWriter#writeEdge(OutputStream, Edge)} or via
* an {@link Edge} passed to {@link GryoWriter#writeObject(OutputStream, Object)}.
*
* @param inputStream a stream containing at least one {@link Edge} as defined by the accompanying
* {@link GraphWriter#writeEdge(OutputStream, Edge)} method.
* @param edgeAttachMethod a function that creates re-attaches a {@link Edge} to a {@link Host} object.
*/
@Override
public Edge readEdge(final InputStream inputStream, final Function<Attachable<Edge>, Edge> edgeAttachMethod) throws IOException {
final Input input = new Input(inputStream);
readHeader(input);
final Attachable<Edge> attachable = kryo.readObject(input, DetachedEdge.class);
return edgeAttachMethod.apply(attachable);
}
/**
* Read a {@link VertexProperty} from output generated by
* {@link GryoWriter#writeVertexProperty(OutputStream, VertexProperty)} or via an {@link VertexProperty} passed
* to {@link GryoWriter#writeObject(OutputStream, Object)}.
*
* @param inputStream a stream containing at least one {@link VertexProperty} as written by the accompanying
* {@link GraphWriter#writeVertexProperty(OutputStream, VertexProperty)} method.
* @param vertexPropertyAttachMethod a function that creates re-attaches a {@link VertexProperty} to a
* {@link Host} object.
*/
@Override
public VertexProperty readVertexProperty(final InputStream inputStream,
final Function<Attachable<VertexProperty>, VertexProperty> vertexPropertyAttachMethod) throws IOException {
final Input input = new Input(inputStream);
readHeader(input);
final Attachable<VertexProperty> attachable = kryo.readObject(input, DetachedVertexProperty.class);
return vertexPropertyAttachMethod.apply(attachable);
}
/**
* Read a {@link Property} from output generated by {@link GryoWriter#writeProperty(OutputStream, Property)} or
* via an {@link Property} passed to {@link GryoWriter#writeObject(OutputStream, Object)}.
*
* @param inputStream a stream containing at least one {@link Property} as written by the accompanying
* {@link GraphWriter#writeProperty(OutputStream, Property)} method.
* @param propertyAttachMethod a function that creates re-attaches a {@link Property} to a {@link Host} object.
*/
@Override
public Property readProperty(final InputStream inputStream,
final Function<Attachable<Property>, Property> propertyAttachMethod) throws IOException {
final Input input = new Input(inputStream);
readHeader(input);
final Attachable<Property> attachable = kryo.readObject(input, DetachedProperty.class);
return propertyAttachMethod.apply(attachable);
}
/**
* {@inheritDoc}
*/
@Override
public <C> C readObject(final InputStream inputStream, final Class<? extends C> clazz) throws IOException {
return clazz.cast(this.kryo.readClassAndObject(new Input(inputStream)));
}
private Vertex readVertexInternal(final Function<Attachable<Vertex>, Vertex> vertexMaker,
final Function<Attachable<Edge>, Edge> edgeMaker,
final Direction d,
final Input input) throws IOException {
readHeader(input);
final StarGraph starGraph = kryo.readObject(input, StarGraph.class);
// read the terminator
kryo.readClassAndObject(input);
final Vertex v = vertexMaker.apply(starGraph.getStarVertex());
if (edgeMaker != null)
starGraph.getStarVertex().edges(d).forEachRemaining(e -> edgeMaker.apply((Attachable<Edge>) e));
return v;
}
private void readHeader(final Input input) throws IOException {
if (!Arrays.equals(GryoMapper.GIO, input.readBytes(3)))
throw new IOException("Invalid format - first three bytes of header do not match expected value");
// skip the next 13 bytes - for future use
input.readBytes(13);
}
public static Builder build() {
return new Builder();
}
public final static class Builder implements ReaderBuilder<GryoReader> {
private long batchSize = 10000;
/**
* Always use the most recent gryo version by default
*/
private Mapper<Kryo> gryoMapper = GryoMapper.build().create();
private Builder() {
}
/**
* Number of mutations to perform before a commit is executed when using
* {@link GryoReader#readGraph(InputStream, Graph)}.
*/
public Builder batchSize(final long batchSize) {
this.batchSize = batchSize;
return this;
}
/**
* Supply a mapper {@link GryoMapper} instance to use as the serializer for the {@code KryoWriter}.
*/
public Builder mapper(final Mapper<Kryo> gryoMapper) {
this.gryoMapper = gryoMapper;
return this;
}
public GryoReader create() {
return new GryoReader(batchSize, this.gryoMapper);
}
}
private class VertexInputIterator implements Iterator<Vertex> {
private final Input input;
private final Function<Attachable<Vertex>, Vertex> vertexMaker;
private final Direction d;
private final Function<Attachable<Edge>, Edge> edgeMaker;
public VertexInputIterator(final Input input,
final Function<Attachable<Vertex>, Vertex> vertexMaker,
final Direction d,
final Function<Attachable<Edge>, Edge> edgeMaker) {
this.input = input;
this.d = d;
this.edgeMaker = edgeMaker;
this.vertexMaker = vertexMaker;
}
@Override
public boolean hasNext() {
return !input.eof();
}
@Override
public Vertex next() {
try {
return readVertexInternal(vertexMaker, edgeMaker, d, input);
} catch (Exception ex) {
throw new RuntimeException(ex);
}
}
}
}