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 com.alibaba.dts.common;
  
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  
  public class FieldEntryHolder {
      private final List<Object> originFields;
      private final Iterator<Object> iterator;
      private final List<Object> filteredFields;
      public FieldEntryHolder(List<Object> originFields) {
          this.originFields = originFields;
          if (null == originFields) {
              this.filteredFields = null;
              this.iterator = null;
          } else {
              this.filteredFields = new LinkedList<>();
              this.iterator = originFields.iterator();
          }
      }
  
      public boolean hasNext() {
          if (iterator == null) {
              return true;
          }
          return iterator.hasNext();
      }
  
      public void skip() {
          if (null != iterator) {
              iterator.next();
          }
      }
  
      public Object take() {
          if (null != iterator) {
              Object current = iterator.next();
              filteredFields.add(current);
              return  current;
          } else {
              return null;
          }
      }
  }
  