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.gobblin.dataset; import com.google.common.base.Preconditions; import com.google.common.collect.ImmutableMap; import org.apache.gobblin.configuration.State; /** * Singleton {@link DatasetResolver} to convert a Hive {@link DatasetDescriptor} to HDFS {@link DatasetDescriptor} */ public class HiveToHdfsDatasetResolver implements DatasetResolver { public static final String HIVE_TABLE = "hiveTable"; public static final HiveToHdfsDatasetResolver INSTANCE = new HiveToHdfsDatasetResolver(); private HiveToHdfsDatasetResolver() { // To make it singleton } @Override public DatasetDescriptor resolve(DatasetDescriptor raw, State state) { ImmutableMap<String, String> metadata = raw.getMetadata(); Preconditions.checkArgument(metadata.containsKey(DatasetConstants.FS_SCHEME), String.format("Hive Dataset Descriptor must contain metadata %s to create Hdfs Dataset Descriptor", DatasetConstants.FS_SCHEME)); Preconditions.checkArgument(metadata.containsKey(DatasetConstants.FS_SCHEME), String.format("Hive Dataset Descriptor must contain metadata %s to create Hdfs Dataset Descriptor", DatasetConstants.FS_LOCATION)); DatasetDescriptor datasetDescriptor = new DatasetDescriptor(metadata.get(DatasetConstants.FS_SCHEME), metadata.get(DatasetConstants.FS_LOCATION)); datasetDescriptor.addMetadata(HIVE_TABLE, raw.getName()); return datasetDescriptor; } }