content: package com.airhacks.enhydrator.functions;
  
  /*
   * #%L
   * enhydrator
   * %%
   * Copyright (C) 2014 Adam Bien
   * %%
   * Licensed 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.
   * #L%
   */
  import com.airhacks.enhydrator.in.Row;
  import com.airhacks.enhydrator.transform.RowTransformer;
  import java.util.Objects;
  
  /**
   *
   * @author airhacks.com
   */
  public class NonRecursiveTree implements RowTransformer {
  
      private Row root;
  
      private final String parentIndicator;
      private final String idColumn;
  
      public NonRecursiveTree(String idColumn, String parentIndicator) {
          Objects.requireNonNull(parentIndicator, "Column for parent indication cannot be null");
          Objects.requireNonNull(idColumn, "ID Column cannot be null");
          this.parentIndicator = parentIndicator;
          this.idColumn = idColumn;
      }
  
      @Override
      public Row execute(Row input) {
          if (input == null) {
              return null;
          }
          if (isParent(input)) {
              this.root = input;
              return root;
          } else {
              root.add(input);
              return null;
          }
      }
  
      boolean isParent(Row input) {
          Object idValue = input.getColumnValue(idColumn);
          Object parentValue = input.getColumnValue(this.parentIndicator);
          return parentValue != null && idValue.equals(parentValue);
      }
  }
  