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.arrow.vector.complex.impl;
  
  import java.util.HashMap;
  import java.util.Map;
  import org.apache.arrow.vector.ValueVector;
  import org.apache.arrow.vector.complex.NonNullableStructVector;
  import org.apache.arrow.vector.complex.reader.FieldReader;
  import org.apache.arrow.vector.complex.writer.BaseWriter.StructWriter;
  import org.apache.arrow.vector.types.Types.MinorType;
  import org.apache.arrow.vector.types.pojo.Field;
  
  /**
   * {@link FieldReader} for a single {@link org.apache.arrow.vector.complex.NonNullableStructVector}.
   */
  @SuppressWarnings("unused")
  public class SingleStructReaderImpl extends AbstractFieldReader {
  
    private final NonNullableStructVector vector;
    private final Map<String, FieldReader> fields = new HashMap<>();
  
    public SingleStructReaderImpl(NonNullableStructVector vector) {
      this.vector = vector;
    }
  
    private void setChildrenPosition(int index) {
      for (FieldReader r : fields.values()) {
        r.setPosition(index);
      }
    }
  
    @Override
    public Field getField() {
      return vector.getField();
    }
  
    @Override
    public FieldReader reader(String name) {
      FieldReader reader = fields.get(name);
      if (reader == null) {
        ValueVector child = vector.getChild(name);
        if (child == null) {
          reader = NullReader.INSTANCE;
        } else {
          reader = child.getReader();
        }
        fields.put(name, reader);
        reader.setPosition(idx());
      }
      return reader;
    }
  
    @Override
    public void setPosition(int index) {
      super.setPosition(index);
      for (FieldReader r : fields.values()) {
        r.setPosition(index);
      }
    }
  
    @Override
    public Object readObject() {
      return vector.getObject(idx());
    }
  
    @Override
    public MinorType getMinorType() {
      return MinorType.STRUCT;
    }
  
    @Override
    public boolean isSet() {
      return true;
    }
  
    @Override
    public java.util.Iterator<String> iterator() {
      return vector.fieldNameIterator();
    }
  
    @Override
    public void copyAsValue(StructWriter writer) {
      SingleStructWriter impl = (SingleStructWriter) writer;
      impl.container.copyFromSafe(idx(), impl.idx(), vector);
    }
  
    @Override
    public void copyAsField(String name, StructWriter writer) {
      SingleStructWriter impl = (SingleStructWriter) writer.struct(name);
      impl.container.copyFromSafe(idx(), impl.idx(), vector);
    }
  }
  