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.asterix.metadata.valueextractors;
  
  import java.io.ByteArrayInputStream;
  import java.io.DataInput;
  import java.io.DataInputStream;
  import java.io.IOException;
  
  import org.apache.asterix.common.transactions.TxnId;
  import org.apache.asterix.metadata.api.IValueExtractor;
  import org.apache.hyracks.algebricks.common.exceptions.AlgebricksException;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.dataflow.common.data.accessors.ITupleReference;
  import org.apache.hyracks.util.string.UTF8StringReader;
  
  /**
   * Extracts the value of field 'DataypeName' of the first nested type from an
   * ITupleReference that contains a serialized representation of a Datatype
   * metadata entity.
   *
   * TODO Is this class used?
   */
  public class NestedDatatypeNameValueExtractor implements IValueExtractor<String> {
  
      private final String datatypeName;
  
      public NestedDatatypeNameValueExtractor(String datatypeName) {
          this.datatypeName = datatypeName;
      }
  
      private final UTF8StringReader reader = new UTF8StringReader();
  
      @Override
      public String getValue(TxnId txnId, ITupleReference tuple) throws AlgebricksException, HyracksDataException {
          byte[] serRecord = tuple.getFieldData(2);
          int recordStartOffset = tuple.getFieldStart(2);
          int recordLength = tuple.getFieldLength(2);
          ByteArrayInputStream stream = new ByteArrayInputStream(serRecord, recordStartOffset, recordLength);
          DataInput in = new DataInputStream(stream);
          try {
              String nestedType = reader.readUTF(in);
              if (nestedType.equals(datatypeName)) {
                  recordStartOffset = tuple.getFieldStart(1);
                  recordLength = tuple.getFieldLength(1);
                  stream = new ByteArrayInputStream(serRecord, recordStartOffset, recordLength);
                  in = new DataInputStream(stream);
                  return reader.readUTF(in);
              }
          } catch (IOException e) {
              throw HyracksDataException.create(e);
          }
          return null;
      }
  }
  