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.Iterator;
  import org.apache.arrow.vector.complex.reader.FieldReader;
  import org.apache.arrow.vector.complex.writer.BaseWriter.ListWriter;
  import org.apache.arrow.vector.complex.writer.BaseWriter.MapWriter;
  import org.apache.arrow.vector.complex.writer.FieldWriter;
  import org.apache.arrow.vector.holders.DenseUnionHolder;
  import org.apache.arrow.vector.holders.UnionHolder;
  
  /**
   * Base class providing common functionality for {@link FieldReader} implementations.
   *
   * <p>This includes tracking the current index and throwing implementations of optional methods.
   */
  abstract class AbstractBaseReader implements FieldReader {
  
    static final org.slf4j.Logger logger =
        org.slf4j.LoggerFactory.getLogger(AbstractBaseReader.class);
  
    private int index;
  
    public AbstractBaseReader() {
      super();
    }
  
    @Override
    public int getPosition() {
      return index;
    }
  
    @Override
    public void setPosition(int index) {
      this.index = index;
    }
  
    protected int idx() {
      return index;
    }
  
    @Override
    public void reset() {
      index = 0;
    }
  
    @Override
    public Iterator<String> iterator() {
      throw new IllegalStateException("The current reader doesn't support reading as a map.");
    }
  
    @Override
    public boolean next() {
      throw new IllegalStateException("The current reader doesn't support getting next information.");
    }
  
    @Override
    public int size() {
      throw new IllegalStateException("The current reader doesn't support getting size information.");
    }
  
    @Override
    public void read(UnionHolder holder) {
      holder.reader = this;
      holder.isSet = this.isSet() ? 1 : 0;
    }
  
    @Override
    public void read(int index, UnionHolder holder) {
      throw new IllegalStateException("The current reader doesn't support reading union type");
    }
  
    @Override
    public void copyAsValue(UnionWriter writer) {
      throw new IllegalStateException("The current reader doesn't support reading union type");
    }
  
    @Override
    public void read(DenseUnionHolder holder) {
      holder.reader = this;
      holder.isSet = this.isSet() ? 1 : 0;
    }
  
    @Override
    public void read(int index, DenseUnionHolder holder) {
      throw new IllegalStateException("The current reader doesn't support reading dense union type");
    }
  
    @Override
    public void copyAsValue(DenseUnionWriter writer) {
      throw new IllegalStateException("The current reader doesn't support reading dense union type");
    }
  
    @Override
    public void copyAsValue(ListWriter writer) {
      ComplexCopier.copy(this, (FieldWriter) writer);
    }
  
    @Override
    public void copyAsValue(MapWriter writer) {
      ComplexCopier.copy(this, (FieldWriter) writer);
    }
  
    @Override
    public void copyAsValue(ListWriter writer, ExtensionTypeWriterFactory writerFactory) {
      ComplexCopier.copy(this, (FieldWriter) writer, writerFactory);
    }
  
    @Override
    public void copyAsValue(MapWriter writer, ExtensionTypeWriterFactory writerFactory) {
      ComplexCopier.copy(this, (FieldWriter) writer, writerFactory);
    }
  }
  