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.accumulo;
  
  import java.util.List;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.accumulo.core.client.MutationsRejectedException;
  import org.apache.accumulo.core.data.Mutation;
  import org.apache.apex.malhar.lib.db.AbstractAggregateTransactionableStoreOutputOperator;
  
  import com.google.common.collect.Lists;
  
  import com.datatorrent.api.Context.OperatorContext;
  import com.datatorrent.netlet.util.DTThrowable;
  
  /**
   * Base output operator that stores tuples in Accumulo rows.&nbsp; Subclasses should provide implementation of operationMutation method. <br>
   *
   * <br>
   * This class provides a Accumulo output operator that can be used to store
   * tuples in rows in a Accumulo table. It should be extended to provide specific
   * implementation. The extending class should implement operationMutation method
   * and provide a Accumulo Mutation metric object that specifies where and what
   * to store for the tuple in the table.<br>
   *
   * <br>
   * This class provides a batch put where tuples are collected till the end
   * window and they are put on end window
   *
   * Note that since Accumulo doesn't support transactions this store cannot
   * guarantee each tuple is written only once to Accumulo in case the operator is
   * restarted from an earlier checkpoint. It only tries to minimize the number of
   * duplicates limiting it to the tuples that were processed in the window when
   * the operator shutdown.
   * @displayName Abstract Accumulo Output
   * @category Output
   * @tags accumulo, key value
   * @param <T>
   *            The tuple type
   * @since 1.0.4
   */
  public abstract class AbstractAccumuloOutputOperator<T> extends AbstractAggregateTransactionableStoreOutputOperator<T, AccumuloWindowStore>
  {
    private static final transient Logger logger = LoggerFactory.getLogger(AbstractAccumuloOutputOperator.class);
    private final List<T> tuples;
    private transient ProcessingMode mode;
    public ProcessingMode getMode()
    {
      return mode;
    }
  
    public void setMode(ProcessingMode mode)
    {
      this.mode = mode;
    }
  
    public AbstractAccumuloOutputOperator()
    {
      tuples = Lists.newArrayList();
      store = new AccumuloWindowStore();
    }
  
    @Override
    public void processTuple(T tuple)
    {
      tuples.add(tuple);
    }
  
    @Override
    public void storeAggregate()
    {
      try {
        for (T tuple : tuples) {
          Mutation mutation = operationMutation(tuple);
          store.getBatchwriter().addMutation(mutation);
        }
        store.getBatchwriter().flush();
  
      } catch (MutationsRejectedException e) {
        logger.error("unable to write mutations", e);
        DTThrowable.rethrow(e);
      }
      tuples.clear();
    }
  
    /**
     *
     * @param t
     * @return Mutation
     */
    public abstract Mutation operationMutation(T t);
  
    @Override
    public void setup(OperatorContext context)
    {
      mode = context.getValue(context.PROCESSING_MODE);
      if (mode == ProcessingMode.EXACTLY_ONCE) {
        throw new RuntimeException("This operator only supports atmost once and atleast once processing modes");
      }
      if (mode == ProcessingMode.AT_MOST_ONCE) {
        tuples.clear();
      }
      super.setup(context);
    }
  }
  
  