content: /*
   * 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.asterix.external.api;
  
  import java.io.Serializable;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.asterix.common.cluster.IClusterStateManager;
  import org.apache.asterix.common.dataflow.ICcApplicationContext;
  import org.apache.asterix.common.exceptions.AsterixException;
  import org.apache.asterix.common.external.IExternalFilterEvaluatorFactory;
  import org.apache.asterix.external.provider.context.DefaultExternalRuntimeDataContext;
  import org.apache.hyracks.algebricks.common.constraints.AlgebricksAbsolutePartitionConstraint;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.api.application.IServiceContext;
  import org.apache.hyracks.api.context.IHyracksTaskContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.IWarningCollector;
  
  public interface IExternalDataSourceFactory extends Serializable {
  
      /**
       * The data source type indicates whether the data source produces a continuous stream or
       * a set of records
       */
      enum DataSourceType {
          STREAM,
          RECORDS
      }
  
      /**
       * @return The data source type {STREAM or RECORDS}
       */
      DataSourceType getDataSourceType();
  
      /**
       * Specifies on which locations this data source is expected to run.
       *
       * @return
       * @throws AsterixException
       */
      AlgebricksAbsolutePartitionConstraint getPartitionConstraint() throws AlgebricksException;
  
      /**
       * Configure the data parser factory. The passed map contains key value pairs from the
       * submitted AQL statement and any additional pairs added by the compiler
       *
       * @param configuration
       * @param filterEvaluatorFactory
       * @throws AsterixException
       */
      void configure(IServiceContext ctx, Map<String, String> configuration, IWarningCollector warningCollector,
              IExternalFilterEvaluatorFactory filterEvaluatorFactory) throws AlgebricksException, HyracksDataException;
  
      default IExternalDataRuntimeContext createExternalDataRuntimeContext(IHyracksTaskContext context, int partition)
              throws HyracksDataException {
          return new DefaultExternalRuntimeDataContext(context, partition);
      }
  
      /**
       * returns the passed partition constraints if not null, otherwise returns round robin absolute partition
       * constraints that matches the count.
       *
       * @param constraints
       * @param count
       * @return
       * @throws AlgebricksException
       */
      static AlgebricksAbsolutePartitionConstraint getPartitionConstraints(ICcApplicationContext appCtx,
              AlgebricksAbsolutePartitionConstraint constraints, int count) throws AlgebricksException {
          if (constraints == null) {
              IClusterStateManager clusterStateManager = appCtx.getClusterStateManager();
              ArrayList<String> locs = new ArrayList<>();
              Set<String> stores = appCtx.getMetadataProperties().getStores().keySet();
              if (stores.isEmpty()) {
                  throw new AlgebricksException("Configurations don't have any stores");
              }
              int i = 0;
              outer: while (i < count) {
                  Iterator<String> storeIt = stores.iterator();
                  while (storeIt.hasNext()) {
                      String node = storeIt.next();
                      int numIODevices = clusterStateManager.getIODevices(node).length;
                      for (int k = 0; k < numIODevices; k++) {
                          locs.add(node);
                          i++;
                          if (i == count) {
                              break outer;
                          }
                      }
                  }
                  if (i == 0) {
                      throw new AlgebricksException("All stores have 0 IO devices");
                  }
              }
              return new AlgebricksAbsolutePartitionConstraint(locs.toArray(new String[locs.size()]));
          }
          return constraints;
      }
  }
  