| /* |
| * 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; |
| |
| import org.apache.tinkerpop.gremlin.structure.Graph; |
| import org.apache.tinkerpop.gremlin.structure.io.gryo.GryoReader; |
| import org.apache.tinkerpop.gremlin.structure.io.gryo.GryoWriter; |
| |
| import java.io.IOException; |
| import java.io.PipedInputStream; |
| import java.io.PipedOutputStream; |
| |
| import static org.apache.tinkerpop.gremlin.structure.io.IoCore.gryo; |
| |
| /** |
| * {@code GraphMigrator} takes the data in one graph and pipes it to another graph. Uses the {@link GryoReader} |
| * and {@link GryoWriter} by default. Note that this utility is meant as a convenience for "small" graph migrations. |
| * |
| * @author Alex Averbuch (alex.averbuch@gmail.com) |
| * @author Stephen Mallette (http://stephen.genoprime.com) |
| */ |
| public final class GraphMigrator { |
| |
| private GraphMigrator() {} |
| |
| /** |
| * Use Gryo to pipe the data from one graph to another graph. Uses readers and writers generated from each |
| * {@link Graph} via the {@link Graph#io(Io.Builder)} method. |
| */ |
| public static void migrateGraph(final Graph fromGraph, final Graph toGraph) throws IOException { |
| migrateGraph(fromGraph, toGraph, fromGraph.io(gryo()).reader().create(), toGraph.io(gryo()).writer().create()); |
| } |
| |
| /** |
| * Pipe the data from one graph to another graph. It is important that the reader and writer utilize the |
| * same format. |
| * |
| * @param fromGraph the graph to take data from. |
| * @param toGraph the graph to take data to. |
| * @param reader reads from the graph written by the writer. |
| * @param writer writes the graph to be read by the reader. |
| * @throws IOException thrown if there is an error in steam between the two graphs. |
| */ |
| public static void migrateGraph(final Graph fromGraph, final Graph toGraph, |
| final GraphReader reader, final GraphWriter writer) throws IOException { |
| final PipedInputStream inPipe = new PipedInputStream(1024); |
| |
| final PipedOutputStream outPipe = new PipedOutputStream(inPipe) { |
| @Override |
| public void close() throws IOException { |
| while (inPipe.available() > 0) { |
| try { |
| Thread.sleep(500); |
| } catch (InterruptedException e) { |
| // do nothing |
| } |
| } |
| super.close(); |
| } |
| }; |
| |
| new Thread(() -> { |
| try { |
| writer.writeGraph(outPipe, fromGraph); |
| outPipe.flush(); |
| outPipe.close(); |
| } catch (IOException e) { |
| throw new RuntimeException(e); |
| } finally { |
| if (fromGraph.features().graph().supportsTransactions()) fromGraph.tx().rollback(); |
| if (toGraph.features().graph().supportsTransactions()) toGraph.tx().rollback(); |
| } |
| }).start(); |
| |
| reader.readGraph(inPipe, toGraph); |
| } |
| } |