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.couchbase;
  
  import java.util.ArrayList;
  
  import javax.validation.constraints.NotNull;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.apex.malhar.lib.util.PojoUtils;
  import org.apache.apex.malhar.lib.util.PojoUtils.Getter;
  import org.apache.hadoop.classification.InterfaceStability.Evolving;
  
  /**
   * An implementation of Couchbase Output Operator which takes a POJO,serializes it into key,value
   * pair and then writes to couchbase.
   *
   * @displayName Couchbase Output Operator
   * @category Output
   * @tags database, nosql, pojo, couchbase
   * @since 3.0.0
   */
  @Evolving
  public class CouchbasePOJOSetOperator extends AbstractCouchBaseSetOperator<Object>
  {
    private static final Logger logger = LoggerFactory.getLogger(CouchBaseStore.class);
    //Key stored in couchbase is always a string.
    private transient Getter<Object, String> keyGetter;
    //Value stored in Couchbase can be of these data types: boolean,numeric,string,arrays,object,null.
    private transient Getter<Object, ? extends Object> valueGetter;
    @NotNull
    private ArrayList<String> expressions;
  
    /*
     * An ArrayList of Java expressions that will yield the field value from the POJO.
     * Each expression corresponds to one column in the Couchbase table.
     */
    public ArrayList<String> getExpressions()
    {
      return expressions;
    }
  
    public void setExpressions(ArrayList<String> expressions)
    {
      this.expressions = expressions;
    }
  
    @Override
    public String getKey(Object tuple)
    {
      // first tuple
      if (null == keyGetter) {
        Class<?> tupleClass = tuple.getClass();
        keyGetter = PojoUtils.createGetter(tupleClass, expressions.get(0), String.class);
      }
      String key = keyGetter.get(tuple);
      logger.debug("key is {}", key);
      return key;
    }
  
    @Override
    public Object getValue(Object tuple)
    {
      Object value = null;
      if (null == valueGetter) {
        Class<?> tupleClass = tuple.getClass();
        final String getterExpression = expressions.get(1);
        valueGetter = PojoUtils.createGetter(tupleClass, getterExpression, Object.class);
      }
      if (valueGetter != null) {
        value = valueGetter.get(tuple);
      }
      logger.debug("value is {}", value);
      return value;
    }
  
  }
  