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.nio.ByteBuffer;
  
  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.dataflow.value.ITypeTraits;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.dataflow.common.data.accessors.ITupleReference;
  import org.apache.hyracks.storage.am.common.api.INullIntrospector;
  import org.apache.hyracks.storage.am.common.tuples.TypeAwareTupleReference;
  import org.apache.hyracks.storage.am.common.tuples.TypeAwareTupleWriter;
  
  /**
   * Returns a copy of the given input tuple.
   */
  public class TupleCopyValueExtractor implements IValueExtractor<ITupleReference> {
      private final TypeAwareTupleWriter tupleWriter;
      private final TypeAwareTupleReference tupleReference;
      // TODO: Try avoid reallocating the tupleBytes.
      // TODO: Get rid of the ByteBuffer by chancing the TypeAwareTupleReference
      // reset() interface.
      private byte[] tupleBytes;
      private ByteBuffer buf;
  
      public TupleCopyValueExtractor(ITypeTraits[] typeTraits, ITypeTraits nullTypeTraits,
              INullIntrospector nullIntrospector) {
          this.tupleWriter = new TypeAwareTupleWriter(typeTraits, nullTypeTraits, nullIntrospector);
          this.tupleReference = tupleWriter.createTupleReference();
      }
  
      @Override
      public ITupleReference getValue(TxnId txnId, ITupleReference tuple)
              throws AlgebricksException, HyracksDataException {
          int numBytes = tupleWriter.bytesRequired(tuple);
          tupleBytes = new byte[numBytes];
          tupleWriter.writeTuple(tuple, tupleBytes, 0);
          buf = ByteBuffer.wrap(tupleBytes);
          tupleReference.resetByTupleOffset(buf.array(), 0);
          return tupleReference;
      }
  }
  