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.apex.malhar.contrib.elasticsearch;
  
  import org.elasticsearch.action.search.SearchRequestBuilder;
  import org.elasticsearch.action.search.SearchResponse;
  import org.elasticsearch.search.SearchHit;
  
  import org.apache.apex.malhar.lib.db.AbstractStoreInputOperator;
  
  import com.datatorrent.api.Context.OperatorContext;
  
  /**
   * This is the base implementation for a non transactional input operator for ElasticSearch
   * <br>
   * Ports:<br>
   * <b>Input</b>: no input port<br>
   * <b>Output</b>: You can have one output port<br>
   * <br>
   * Compile time checks:<br>
   * None<br>
   * <br>
   * Run time checks:<br>
   * hostName port<br>
   *
   * <b>Benchmarks</b>: <br>
   *
   * @displayName Elastic Search Input
   * @category Input
   * @tags elastic search
   *
   * @since 2.1.0
   */
  public abstract class AbstractElasticSearchInputOperator<T, S extends ElasticSearchConnectable> extends AbstractStoreInputOperator<T, S>
  {
    protected transient SearchRequestBuilder searchRequestBuilder;
  
    /**
     * Initializing transient fields such as ElasticSearchConnectable, SearchRequestBuilder
     *
     * @see org.apache.apex.malhar.lib.db.AbstractStoreInputOperator#setup(com.datatorrent.api.Context.OperatorContext)
     */
    @Override
    public void setup(OperatorContext t1)
    {
      super.setup(t1);
      this.searchRequestBuilder = new SearchRequestBuilder(store.client);
    }
  
    /**
     * Emit one tuple per {@code SearchHit} for given search query
     *
     * @see com.datatorrent.api.InputOperator#emitTuples()
     */
    @Override
    public void emitTuples()
    {
      SearchResponse response = getSearchRequestBuilder().execute().actionGet();
      for (SearchHit hit : response.getHits().hits()) {
        T tuple = convertToTuple(hit);
        if (tuple != null) {
          outputPort.emit(tuple);
        }
      }
    }
  
    /**
     * Converts SearchHit to Tuple
     *
     * @param hit
     * @return tuple constructed from <code>hit</code>
     */
    protected abstract T convertToTuple(SearchHit hit);
  
    /**
     * Set {@link SearchRequestBuilder} properties according to search query requirements. Properties which do not change
     * for each window can be set in {@code setup()}. Properties which may change for each window should be set in this
     * function
     *
     * @return {@link SearchRequestBuilder}
     */
    protected abstract SearchRequestBuilder getSearchRequestBuilder();
  
  }
  