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.nifi;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import org.apache.apex.malhar.lib.wal.WindowDataManager;
  import org.apache.nifi.remote.client.SiteToSiteClient;
  
  import com.datatorrent.api.DefaultInputPort;
  
  /**
   * NiFi output adapter operator with a single input port. Clients should provide a NiFiDataPacketBuilder implementation
   * for converting incoming tuples to NiFiDataPackets.
   * <p>
   * <br>
   * Ports:<br>
   * <b>Input</b>: Have only one input port<br>
   * <b>Output</b>: No output port<br>
   * <br>
   * Properties:<br>
   * None<br>
   * <br>
   * Compile time checks:<br>
   * None<br>
   * <br>
   * Run time checks:<br>
   * None<br>
   * <br>
   * Benchmarks:<br>
   * TBD<br>
   * <br>
   * </p>
   *
   * @displayName NiFi Single Port Output
   * @category Messaging
   * @tags output operator
   *
   *
   * @since 3.4.0
   */
  public class NiFiSinglePortOutputOperator<T> extends AbstractNiFiOutputOperator<T>
  {
  
    public final transient BufferingInputPort inputPort;
  
    // required by Kyro serialization
    private NiFiSinglePortOutputOperator()
    {
      this(null, null, null, 0);
    }
  
    /**
     * @param siteToSiteBuilder the builder for a NiFi SiteToSiteClient
     * @param dataPacketBuilder a builder to produce NiFiDataPackets from incoming data
     * @param windowDataManager  a WindowDataManager to save and load state for windows of tuples
     * @param batchSize the maximum number of tuples to send to NiFi in a single transaction
     */
    public NiFiSinglePortOutputOperator(
        final SiteToSiteClient.Builder siteToSiteBuilder,
        final NiFiDataPacketBuilder<T> dataPacketBuilder,
        final WindowDataManager windowDataManager,
        final int batchSize)
    {
      super(siteToSiteBuilder, dataPacketBuilder, windowDataManager);
      this.inputPort = new BufferingInputPort(batchSize);
    }
  
    @Override
    protected void endNewWindow()
    {
      // flush any tuples that may have been buffered between the last flush and endWindow()
      inputPort.flush();
    }
  
    /**
     * An InputPort that accumulates tuples up to the provided batch size before flushing.
     */
    public class BufferingInputPort extends DefaultInputPort<T>
    {
  
      private final int batchSize;
      private final List<T> tuples;
  
      public BufferingInputPort(final int batchSize)
      {
        this.tuples = new ArrayList<>();
        this.batchSize = batchSize;
      }
  
      @Override
      public void process(T tuple)
      {
        if (!skipProcessingTuple) {
          tuples.add(tuple);
  
          if (tuples.size() >= batchSize) {
            flush();
          }
        }
      }
  
      public void flush()
      {
        processTuples(tuples);
        tuples.clear();
      }
  
    }
  
  }
  