Java tutorial
/* * 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.hadoop.structure.util; import org.apache.commons.configuration.BaseConfiguration; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.mapreduce.InputFormat; import org.apache.tinkerpop.gremlin.hadoop.Constants; import org.apache.tinkerpop.gremlin.hadoop.structure.io.VertexWritable; /** * @author Marko A. Rodriguez (http://markorodriguez.com) */ public final class ConfUtil { private ConfUtil() { } public static org.apache.commons.configuration.Configuration makeApacheConfiguration( final Configuration hadoopConfiguration) { final BaseConfiguration apacheConfiguration = new BaseConfiguration(); apacheConfiguration.setDelimiterParsingDisabled(true); hadoopConfiguration.iterator() .forEachRemaining(e -> apacheConfiguration.setProperty(e.getKey(), e.getValue())); return apacheConfiguration; } public static Configuration makeHadoopConfiguration( final org.apache.commons.configuration.Configuration apacheConfiguration) { final Configuration hadoopConfiguration = new Configuration(); apacheConfiguration.getKeys().forEachRemaining(key -> { final Object object = apacheConfiguration.getProperty(key); hadoopConfiguration.set(key, object.toString()); }); return hadoopConfiguration; } public static void mergeApacheIntoHadoopConfiguration( final org.apache.commons.configuration.Configuration apacheConfiguration, final Configuration hadoopConfiguration) { apacheConfiguration.getKeys().forEachRemaining(key -> { final Object object = apacheConfiguration.getProperty(key); hadoopConfiguration.set(key, object.toString()); }); } public static InputFormat<NullWritable, VertexWritable> getReaderAsInputFormat( final Configuration hadoopConfiguration) { final Class<?> readerClass = hadoopConfiguration.getClass(Constants.GREMLIN_HADOOP_GRAPH_READER, Object.class); try { return InputFormat.class.isAssignableFrom(readerClass) ? (InputFormat<NullWritable, VertexWritable>) readerClass.newInstance() : (InputFormat<NullWritable, VertexWritable>) Class .forName("org.apache.tinkerpop.gremlin.spark.structure.io.InputRDDFormat") .newInstance(); } catch (final Exception e) { throw new IllegalStateException(e.getMessage(), e); } } }