core/src/main/java/org/apache/hcatalog/mapreduce/HCatInputFormat.java

/**
 * 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.hcatalog.mapreduce;

import java.io.IOException;
import java.util.Properties;

import com.google.common.base.Preconditions;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.Job;

/**
 * The InputFormat to use to read data from HCatalog.
 */
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class HCatInputFormat extends HCatBaseInputFormat {

    private Configuration conf;
    private InputJobInfo inputJobInfo;

    /**
     * @deprecated as of release 0.5, and will be removed in a future release
     */
    @Deprecated
    public static void setInput(Job job, InputJobInfo inputJobInfo) throws IOException {
        setInput(job.getConfiguration(), inputJobInfo);
    }

    /**
     * @deprecated as of release 0.5, and will be removed in a future release
     */
    @Deprecated
    public static void setInput(Configuration conf, InputJobInfo inputJobInfo) throws IOException {
        setInput(conf, inputJobInfo.getDatabaseName(), inputJobInfo.getTableName())
            .setFilter(inputJobInfo.getFilter())
            .setProperties(inputJobInfo.getProperties());
    }

    /**
     * See {@link #setInput(org.apache.hadoop.conf.Configuration, String, String)}
     */
    public static HCatInputFormat setInput(Job job, String dbName, String tableName) throws IOException {
        return setInput(job.getConfiguration(), dbName, tableName);
    }

    /**
     * Set inputs to use for the job. This queries the metastore with the given input
     * specification and serializes matching partitions into the job conf for use by MR tasks.
     * @param conf the job configuration
     * @param dbName database name, which if null 'default' is used
     * @param tableName table name
     * @throws IOException on all errors
     */
    public static HCatInputFormat setInput(Configuration conf, String dbName, String tableName)
        throws IOException {

        Preconditions.checkNotNull(conf, "required argument 'conf' is null");
        Preconditions.checkNotNull(tableName, "required argument 'tableName' is null");

        HCatInputFormat hCatInputFormat = new HCatInputFormat();
        hCatInputFormat.conf = conf;
        hCatInputFormat.inputJobInfo = InputJobInfo.create(dbName, tableName, null, null);

        try {
            InitializeInput.setInput(conf, hCatInputFormat.inputJobInfo);
        } catch (Exception e) {
            throw new IOException(e);
        }

        return hCatInputFormat;
    }

    /**
     * Set a filter on the input table.
     * @param filter the filter specification, which may be null
     * @return this
     * @throws IOException on all errors
     */
    public HCatInputFormat setFilter(String filter) throws IOException {
        // null filters are supported to simplify client code
        if (filter != null) {
            inputJobInfo = InputJobInfo.create(
                inputJobInfo.getDatabaseName(),
                inputJobInfo.getTableName(),
                filter,
                inputJobInfo.getProperties());
            try {
                InitializeInput.setInput(conf, inputJobInfo);
            } catch (Exception e) {
                throw new IOException(e);
            }
        }
        return this;
    }

    /**
     * Set properties for the input format.
     * @param properties properties for the input specification
     * @return this
     * @throws IOException on all errors
     */
    public HCatInputFormat setProperties(Properties properties) throws IOException {
        Preconditions.checkNotNull(properties, "required argument 'properties' is null");
        inputJobInfo = InputJobInfo.create(
            inputJobInfo.getDatabaseName(),
            inputJobInfo.getTableName(),
            inputJobInfo.getFilter(),
            properties);
        try {
            InitializeInput.setInput(conf, inputJobInfo);
        } catch (Exception e) {
            throw new IOException(e);
        }
        return this;
    }
}