gobblin.hive.HiveSchemaManager.java Source code

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Here is the source code for gobblin.hive.HiveSchemaManager.java

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/*
 * Copyright (C) 2014-2016 LinkedIn Corp. All rights reserved.
 *
 * Licensed 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.
 */

package gobblin.hive;

import org.apache.commons.lang3.reflect.ConstructorUtils;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.metastore.api.SerDeInfo;

import com.google.common.base.Enums;
import com.google.common.base.Optional;

import gobblin.configuration.State;
import gobblin.hive.avro.HiveAvroSchemaManager;
import lombok.extern.slf4j.Slf4j;

/**
 * This class manages the schema for Hive registration.
 *
 * @author ziliu
 */
@Slf4j
public abstract class HiveSchemaManager {

    protected final State props;

    protected HiveSchemaManager(State props) {
        this.props = props;
    }

    /**
     * Add the appropriate schema properties to the given {@link SerDeInfo}.
     *
     * For example, when registering Avro tables, one needs to specify either
     * {@link org.apache.hadoop.hive.serde2.avro.AvroSerdeUtils.AvroTableProperties#SCHEMA_LITERAL}
     * or {@link org.apache.hadoop.hive.serde2.avro.AvroSerdeUtils.AvroTableProperties#SCHEMA_URL}
     * in the {@link SerDeInfo}.
     */
    public abstract void addSchemaProperties(SerDeInfo si, Path path);

    public enum Implementation {
        NOP(HiveNopSchemaManager.class.getName()), AVRO(HiveAvroSchemaManager.class.getName());

        private final String schemaManagerClassName;

        private Implementation(String schemaManagerClassName) {
            this.schemaManagerClassName = schemaManagerClassName;
        }

        @Override
        public String toString() {
            return this.schemaManagerClassName;
        }
    }

    /**
     * Get an instance of {@link HiveSchemaManager}.
     *
     * @param type The {@link HiveSchemaManager} type. It could be AVRO, NOP or the name of a class that implements
     * {@link HiveSchemaManager}. The specified {@link HiveSchemaManager} type must have a constructor that takes a
     * {@link State} object.
     * @param props A {@link State} object used to instantiate {@link HiveSchemaManager}.
     */
    public static HiveSchemaManager getInstance(String type, State props) {
        Optional<Implementation> implementation = Enums.getIfPresent(Implementation.class, type.toUpperCase());
        if (implementation.isPresent()) {
            try {
                return (HiveSchemaManager) ConstructorUtils
                        .invokeConstructor(Class.forName(implementation.get().toString()), props);
            } catch (ReflectiveOperationException e) {
                throw new RuntimeException(
                        "Unable to instantiate " + HiveSchemaManager.class.getSimpleName() + " with type " + type,
                        e);
            }
        } else {
            log.info(String.format("%s with type %s does not exist. Using %s",
                    HiveSchemaManager.class.getSimpleName(), type, HiveNopSchemaManager.class.getSimpleName()));
            return new HiveNopSchemaManager(props);
        }
    }

}