examples/spark/src/main/java/org/apache/carbondata/examples/sdk/SDKS3ReadExample.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.carbondata.examples.sdk;

import java.util.List;

import org.apache.carbondata.common.logging.LogServiceFactory;
import org.apache.carbondata.core.metadata.datatype.DataTypes;
import org.apache.carbondata.core.scan.expression.ColumnExpression;
import org.apache.carbondata.core.scan.expression.LiteralExpression;
import org.apache.carbondata.core.scan.expression.conditional.EqualToExpression;
import org.apache.carbondata.core.util.path.CarbonTablePath;
import org.apache.carbondata.sdk.file.CarbonReader;

import static org.apache.carbondata.sdk.file.utils.SDKUtil.listFiles;

import org.apache.hadoop.conf.Configuration;
import org.apache.log4j.Logger;

import static org.apache.hadoop.fs.s3a.Constants.ACCESS_KEY;
import static org.apache.hadoop.fs.s3a.Constants.ENDPOINT;
import static org.apache.hadoop.fs.s3a.Constants.SECRET_KEY;

/**
 * Example for testing carbonReader on S3
 */
public class SDKS3ReadExample {
  public static void main(String[] args) throws Exception {
    Logger logger = LogServiceFactory.getLogService(SDKS3ReadExample.class.getName());
    int parameterLength = 3;
    if (args == null || args.length < parameterLength) {
      logger.error("Usage: java CarbonS3Example: <access-key> <secret-key>"
          + "<s3-endpoint> [table-path-on-s3]");
      System.exit(0);
    }

    String path = "s3a://obs-xubo4/sdkdata/test";
    if (args.length > parameterLength) {
      path = args[3];
    }

    // 1. read with file list
    Configuration conf = new Configuration();

    conf.set(ACCESS_KEY, args[0]);
    conf.set(SECRET_KEY, args[1]);
    conf.set(ENDPOINT, args[2]);
    List fileLists = listFiles(path, CarbonTablePath.CARBON_DATA_EXT, conf);

    // Read data
    EqualToExpression equalToExpression = new EqualToExpression(
        new ColumnExpression("name", DataTypes.STRING),
        new LiteralExpression("robot1", DataTypes.STRING));

    CarbonReader reader = CarbonReader
        .builder()
        .projection(new String[]{"name", "age"})
        .filter(equalToExpression)
        .withHadoopConf(ACCESS_KEY, args[0])
        .withHadoopConf(SECRET_KEY, args[1])
        .withHadoopConf(ENDPOINT, args[2])
        .withFileLists(fileLists)
        .build();

    System.out.println("\nData:");
    int i = 0;
    int count = 20;
    while (i < count && reader.hasNext()) {
      Object[] row = (Object[]) reader.readNextRow();
      System.out.println(row[0] + " " + row[1]);
      i++;
    }
    System.out.println("\nFinished");
    reader.close();

    // Read without filter
    CarbonReader reader2 = CarbonReader
        .builder(path, "_temp")
        .projection(new String[]{"name", "age"})
        .withHadoopConf(ACCESS_KEY, args[0])
        .withHadoopConf(SECRET_KEY, args[1])
        .withHadoopConf(ENDPOINT, args[2])
        .build();

    System.out.println("\nData:");
    i = 0;
    while (i < count && reader2.hasNext()) {
      Object[] row = (Object[]) reader2.readNextRow();
      System.out.println(row[0] + " " + row[1]);
      i++;
    }
    System.out.println("\nFinished");
    reader2.close();
  }
}