lens-storage-db/src/main/java/org/apache/lens/storage/db/DBSerde.java

/**
 * 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.lens.storage.db;


import static org.apache.hadoop.hive.serde.serdeConstants.LIST_COLUMNS;
import static org.apache.hadoop.hive.serde.serdeConstants.LIST_COLUMN_TYPES;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Properties;

import org.apache.commons.lang.NotImplementedException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hive.serde2.AbstractSerDe;
import org.apache.hadoop.hive.serde2.SerDeException;
import org.apache.hadoop.hive.serde2.SerDeStats;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfoUtils;
import org.apache.hadoop.io.Writable;

/**
 * The Class DBSerde.
 */
public class DBSerde extends AbstractSerDe {

  /**
   * The cached object inspector.
   */
  private ObjectInspector cachedObjectInspector;

  /*
   * (non-Javadoc)
   *
   * @see org.apache.hadoop.hive.serde2.AbstractSerDe#deserialize(org.apache.hadoop.io.Writable)
   */
  @Override
  public Object deserialize(Writable arg0) throws SerDeException {
    throw new NotImplementedException();
  }

  @Override
  public ObjectInspector getObjectInspector() throws SerDeException {
    return cachedObjectInspector;
  }

  @Override
  public SerDeStats getSerDeStats() {
    return null;
  }

  /*
   * (non-Javadoc)
   *
   * @see org.apache.hadoop.hive.serde2.AbstractSerDe#initialize(org.apache.hadoop.conf.Configuration,
   * java.util.Properties)
   */
  @Override
  public void initialize(Configuration conf, Properties tbl) throws SerDeException {
    String columnNameProperty = tbl.getProperty(LIST_COLUMNS);
    String columnTypeProperty = tbl.getProperty(LIST_COLUMN_TYPES);
    List<String> columnNames = Arrays.asList(columnNameProperty.split(","));
    List<TypeInfo> columnTypes = TypeInfoUtils.getTypeInfosFromTypeString(columnTypeProperty);

    List<ObjectInspector> columnObjectInspectors = new ArrayList<ObjectInspector>(columnNames.size());
    ObjectInspector colObjectInspector;
    for (int col = 0; col < columnNames.size(); col++) {
      colObjectInspector = TypeInfoUtils.getStandardJavaObjectInspectorFromTypeInfo(columnTypes.get(col));
      columnObjectInspectors.add(colObjectInspector);
    }

    cachedObjectInspector = ObjectInspectorFactory
      .getColumnarStructObjectInspector(columnNames, columnObjectInspectors);
  }

  @Override
  public Class<? extends Writable> getSerializedClass() {
    return null;
  }

  /*
   * (non-Javadoc)
   *
   * @see org.apache.hadoop.hive.serde2.AbstractSerDe#serialize(java.lang.Object,
   * org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector)
   */
  @Override
  public Writable serialize(Object arg0, ObjectInspector arg1) throws SerDeException {
    throw new NotImplementedException();
  }

}