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.flink.connectors.kudu.connector.writer;
  
  import org.apache.flink.annotation.PublicEvolving;
  import org.apache.kudu.client.KuduTable;
  import org.apache.kudu.client.Operation;
  import org.apache.kudu.client.PartialRow;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.Optional;
  
  /**
   * Base implementation for {@link KuduOperationMapper}s that have one-to-one input to
   * Kudu operation mapping. It requires a fixed table schema to be provided at construction
   * time and only requires users to implement a getter for a specific column index (relative
   * to the ones provided in the constructor).
   * <br>
   * Supports both fixed operation type per record by specifying the {@link KuduOperation} or a
   * custom implementation for creating the base {@link Operation} throwugh the
   * {@link #createBaseOperation(Object, KuduTable)} method.
   *
   * @param <T> Input type
   */
  @PublicEvolving
  public abstract class AbstractSingleOperationMapper<T> implements KuduOperationMapper<T> {
  
      protected final String[] columnNames;
      private final KuduOperation operation;
  
      protected AbstractSingleOperationMapper(String[] columnNames) {
          this(columnNames, null);
      }
  
      public AbstractSingleOperationMapper(String[] columnNames, KuduOperation operation) {
          this.columnNames = columnNames;
          this.operation = operation;
      }
  
      /**
       * Returns the object corresponding to the given column index.
       *
       * @param input Input element
       * @param i     Column index
       * @return Column value
       */
      public abstract Object getField(T input, int i);
  
      public Optional<Operation> createBaseOperation(T input, KuduTable table) {
          if (operation == null) {
              throw new UnsupportedOperationException("createBaseOperation must be overridden if no operation specified in constructor");
          }
          switch (operation) {
              case INSERT:
                  return Optional.of(table.newInsert());
              case UPDATE:
                  return Optional.of(table.newUpdate());
              case UPSERT:
                  return Optional.of(table.newUpsert());
              case DELETE:
                  return Optional.of(table.newDelete());
              default:
                  throw new RuntimeException("Unknown operation " + operation);
          }
      }
  
      @Override
      public List<Operation> createOperations(T input, KuduTable table) {
          Optional<Operation> operationOpt = createBaseOperation(input, table);
          if (!operationOpt.isPresent()) {
              return Collections.emptyList();
          }
  
          Operation operation = operationOpt.get();
          PartialRow partialRow = operation.getRow();
  
          for (int i = 0; i < columnNames.length; i++) {
              partialRow.addObject(columnNames[i], getField(input, i));
          }
  
          return Collections.singletonList(operation);
      }
  
      public enum KuduOperation {
          INSERT,
          UPDATE,
          UPSERT,
          DELETE
      }
  }
  