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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,
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"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
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*/
package org.apache.griffin.measure.datasource

import scala.util.Success

import org.apache.spark.sql.SparkSession
import org.apache.spark.streaming.StreamingContext

import org.apache.griffin.measure.Loggable
import org.apache.griffin.measure.configuration.dqdefinition.DataSourceParam
import org.apache.griffin.measure.datasource.cache.StreamingCacheClientFactory
import org.apache.griffin.measure.datasource.connector.{DataConnector, DataConnectorFactory}


object DataSourceFactory extends Loggable {

  def getDataSources(sparkSession: SparkSession,
                     ssc: StreamingContext,
                     dataSources: Seq[DataSourceParam]
                    ): Seq[DataSource] = {
    dataSources.zipWithIndex.flatMap { pair =>
      val (param, index) = pair
      getDataSource(sparkSession, ssc, param, index)
    }
  }

  private def getDataSource(sparkSession: SparkSession,
                            ssc: StreamingContext,
                            dataSourceParam: DataSourceParam,
                            index: Int
                           ): Option[DataSource] = {
    val name = dataSourceParam.getName
    val connectorParams = dataSourceParam.getConnectors
    val timestampStorage = TimestampStorage()

    // for streaming data cache
    val streamingCacheClientOpt = StreamingCacheClientFactory.getClientOpt(
      sparkSession.sqlContext, dataSourceParam.getCheckpointOpt, name, index, timestampStorage)

    val dataConnectors: Seq[DataConnector] = connectorParams.flatMap { connectorParam =>
      DataConnectorFactory.getDataConnector(sparkSession, ssc, connectorParam,
        timestampStorage, streamingCacheClientOpt) match {
          case Success(connector) => Some(connector)
          case _ => None
        }
    }

    Some(DataSource(name, dataSourceParam, dataConnectors, streamingCacheClientOpt))
  }

}