scala source code of DefaultSource

/*
 * 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,
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 * See the License for the specific language governing permissions and
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package io.github.tmheo.spark.athena

import org.apache.spark.sql.SQLContext
import org.apache.spark.sql.sources._

class DefaultSource extends RelationProvider {

  override def createRelation(
                               sqlContext: SQLContext,
                               parameters: Map[String, String]): BaseRelation = {
    val jdbcOptions = new JDBCOptions(parameters)
    val partitionColumn = jdbcOptions.partitionColumn
    val lowerBound = jdbcOptions.lowerBound
    val upperBound = jdbcOptions.upperBound
    val numPartitions = jdbcOptions.numPartitions

    val partitionInfo = if (partitionColumn.isEmpty) {
      assert(lowerBound.isEmpty && upperBound.isEmpty)
      null
    } else {
      assert(lowerBound.nonEmpty && upperBound.nonEmpty && numPartitions.nonEmpty)
      JDBCPartitioningInfo(
        partitionColumn.get, lowerBound.get, upperBound.get, numPartitions.get)
    }
    val parts = JDBCRelation.columnPartition(partitionInfo)
    JDBCRelation(parts, jdbcOptions)(sqlContext.sparkSession)
  }

}