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.runtime.evaluators.functions;
  
  import java.io.DataOutput;
  import java.io.IOException;
  
  import org.apache.asterix.om.functions.BuiltinFunctions;
  import org.apache.asterix.om.functions.IFunctionDescriptorFactory;
  import org.apache.asterix.om.types.ATypeTag;
  import org.apache.asterix.runtime.evaluators.base.AbstractScalarFunctionDynamicDescriptor;
  import org.apache.hyracks.algebricks.core.algebra.functions.FunctionIdentifier;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluator;
  import org.apache.hyracks.algebricks.runtime.base.IScalarEvaluatorFactory;
  import org.apache.hyracks.api.context.IEvaluatorContext;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  import org.apache.hyracks.data.std.api.IPointable;
  import org.apache.hyracks.data.std.primitive.VoidPointable;
  import org.apache.hyracks.data.std.util.ArrayBackedValueStorage;
  import org.apache.hyracks.dataflow.common.data.accessors.IFrameTupleReference;
  import org.apache.hyracks.util.string.UTF8StringWriter;
  
  public class GetTypeDescriptor extends AbstractScalarFunctionDynamicDescriptor {
      public static final IFunctionDescriptorFactory FACTORY = GetTypeDescriptor::new;
      private static final long serialVersionUID = 1L;
  
      @Override
      public IScalarEvaluatorFactory createEvaluatorFactory(final IScalarEvaluatorFactory[] args) {
          return new IScalarEvaluatorFactory() {
              private static final long serialVersionUID = 1L;
  
              @Override
              public IScalarEvaluator createScalarEvaluator(final IEvaluatorContext ctx) throws HyracksDataException {
                  return new IScalarEvaluator() {
                      private ArrayBackedValueStorage resultStorage = new ArrayBackedValueStorage();
                      private DataOutput dataOutput = resultStorage.getDataOutput();
                      private IScalarEvaluator inputEval = args[0].createScalarEvaluator(ctx);
                      private final IPointable inputArg = new VoidPointable();
                      private final UTF8StringWriter writer = new UTF8StringWriter();
  
                      @Override
                      public void evaluate(IFrameTupleReference tuple, IPointable result) throws HyracksDataException {
                          resultStorage.reset();
                          inputEval.evaluate(tuple, inputArg);
  
                          try {
                              byte[] bytes = inputArg.getByteArray();
                              int offset = inputArg.getStartOffset();
                              dataOutput.writeByte(ATypeTag.SERIALIZED_STRING_TYPE_TAG);
                              writer.writeUTF8(ATypeTag.VALUE_TYPE_MAPPING[bytes[offset]].toString(), dataOutput);
                          } catch (IOException e) {
                              throw HyracksDataException.create(e);
                          }
                          result.set(resultStorage);
                      }
                  };
  
              }
          };
  
      }
  
      @Override
      public FunctionIdentifier getIdentifier() {
          return BuiltinFunctions.GET_TYPE;
      }
  }
  