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.input.stream.factory;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.asterix.common.dataflow.ICcApplicationContext;
  import org.apache.asterix.common.external.IExternalFilterEvaluatorFactory;
  import org.apache.asterix.external.api.AsterixInputStream;
  import org.apache.asterix.external.api.IExternalDataRuntimeContext;
  import org.apache.asterix.external.api.IInputStreamFactory;
  import org.apache.asterix.external.input.stream.TwitterFirehoseInputStream;
  import org.apache.hyracks.algebricks.common.constraints.AlgebricksAbsolutePartitionConstraint;
  import org.apache.hyracks.api.application.IServiceContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.api.exceptions.IWarningCollector;
  
  /**
   * Factory class for creating @see{TwitterFirehoseFeedAdapter}. The adapter
   * simulates a twitter firehose with tweets being "pushed" into Asterix at a
   * configurable rate measured in terms of TPS (tweets/second). The stream of
   * tweets lasts for a configurable duration (measured in seconds).
   */
  public class TwitterFirehoseStreamFactory implements IInputStreamFactory {
  
      private static final long serialVersionUID = 1L;
  
      /**
       * Degree of parallelism for feed ingestion activity. Defaults to 1. This
       * determines the count constraint for the ingestion operator.
       **/
      private static final String KEY_INGESTION_CARDINALITY = "ingestion-cardinality";
  
      /**
       * The absolute locations where ingestion operator instances will be placed.
       **/
      private static final String KEY_INGESTION_LOCATIONS = "ingestion-location";
  
      private Map<String, String> configuration;
      private transient IServiceContext serviceCtx;
  
      @Override
      public AlgebricksAbsolutePartitionConstraint getPartitionConstraint() {
          String ingestionCardinalityParam = configuration.get(KEY_INGESTION_CARDINALITY);
          String ingestionLocationParam = configuration.get(KEY_INGESTION_LOCATIONS);
          String[] locations = null;
          if (ingestionLocationParam != null) {
              locations = ingestionLocationParam.split(",");
          }
          int count = locations != null ? locations.length : 1;
          if (ingestionCardinalityParam != null) {
              count = Integer.parseInt(ingestionCardinalityParam);
          }
          ICcApplicationContext appCtx = (ICcApplicationContext) serviceCtx.getApplicationContext();
          List<String> chosenLocations = new ArrayList<>();
          String[] availableLocations = locations != null ? locations
                  : appCtx.getClusterStateManager().getParticipantNodes().toArray(new String[] {});
          for (int i = 0, k = 0; i < count; i++, k = (k + 1) % availableLocations.length) {
              chosenLocations.add(availableLocations[k]);
          }
          return new AlgebricksAbsolutePartitionConstraint(chosenLocations.toArray(new String[] {}));
      }
  
      @Override
      public DataSourceType getDataSourceType() {
          return DataSourceType.STREAM;
      }
  
      @Override
      public void configure(IServiceContext serviceCtx, Map<String, String> configuration,
              IWarningCollector warningCollector, IExternalFilterEvaluatorFactory filterEvaluatorFactory) {
          this.serviceCtx = serviceCtx;
          this.configuration = configuration;
      }
  
      @Override
      public AsterixInputStream createInputStream(IExternalDataRuntimeContext context) throws HyracksDataException {
          try {
              return new TwitterFirehoseInputStream(configuration, context.getPartition());
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
      }
  }
  