org.apache.hadoop.hive.serde2.columnar.OptimizedLazyBinaryColumnarSerde Maven / Gradle / Ivy

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/*
 * Licensed 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.hadoop.hive.serde2.columnar;

import org.apache.hadoop.hive.serde2.SerDeException;
import org.apache.hadoop.hive.serde2.lazybinary.LazyBinarySerDe;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.StructField;
import org.apache.hadoop.hive.serde2.objectinspector.StructObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
import org.apache.hadoop.io.Writable;

import java.util.List;

/**
 * This is a variant of {@link LazyBinaryColumnarSerDe} that avoids a call to
 * {@code StringObjectInspector.getPrimitiveJavaObject()} in {@code serialize()}
 * to check whether the string is empty (it calls {@code getPrimitiveWritableObject()}
 * instead). This improves CPU efficiency by avoiding turning the underlying bytes into
 * a Java String.
 */
public class OptimizedLazyBinaryColumnarSerde
        extends LazyBinaryColumnarSerDe
{
    @Override
    public Writable serialize(Object obj, ObjectInspector objInspector)
            throws SerDeException
    {
        if (objInspector.getCategory() != ObjectInspector.Category.STRUCT) {
            throw new SerDeException(getClass().toString()
                    + " can only serialize struct types, but we got: "
                    + objInspector.getTypeName());
        }

        StructObjectInspector soi = (StructObjectInspector) objInspector;
        List fields = soi.getAllStructFieldRefs();
        List