    001/*
    002 * Copyright (c) 2007-2017 Xplenty, Inc. All Rights Reserved.
    003 *
    004 * Project and contact information: http://www.cascading.org/
    005 *
    006 * This file is part of the Cascading project.
    007 *
    008 * Licensed under the Apache License, Version 2.0 (the "License");
    009 * you may not use this file except in compliance with the License.
    010 * You may obtain a copy of the License at
    011 *
    012 *     http://www.apache.org/licenses/LICENSE-2.0
    013 *
    014 * Unless required by applicable law or agreed to in writing, software
    015 * distributed under the License is distributed on an "AS IS" BASIS,
    016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    017 * See the License for the specific language governing permissions and
    018 * limitations under the License.
    019 */
    020
    021package cascading.tuple.hadoop.util;
    022
    023import java.io.InputStream;
    024import java.util.Comparator;
    025
    026import cascading.CascadingException;
    027import cascading.tuple.StreamComparator;
    028import cascading.tuple.hadoop.io.HadoopTupleInputStream;
    029
    030/**
    031 *
    032 */
    033public class TypedTupleElementStreamComparator implements StreamComparator<HadoopTupleInputStream>, Comparator<Object>
    034  {
    035  private final Class type;
    036  final StreamComparator comparator;
    037
    038  public TypedTupleElementStreamComparator( Class type, StreamComparator comparator )
    039    {
    040    this.type = type;
    041    this.comparator = comparator;
    042    }
    043
    044  @Override
    045  public int compare( Object lhs, Object rhs )
    046    {
    047    return ( (Comparator<Object>) comparator ).compare( lhs, rhs );
    048    }
    049
    050  @Override
    051  public int compare( HadoopTupleInputStream lhsStream, HadoopTupleInputStream rhsStream )
    052    {
    053    try
    054      {
    055      InputStream lhs = lhsStream.getInputStream();
    056      InputStream rhs = rhsStream.getInputStream();
    057
    058      if( !type.isPrimitive() )
    059        {
    060        int lhsToken = lhsStream.readToken();
    061        int rhsToken = rhsStream.readToken();
    062
    063        lhs = lhsToken == 0 ? null : lhs;
    064        rhs = rhsToken == 0 ? null : rhs;
    065        }
    066
    067      return comparator.compare( lhs, rhs );
    068      }
    069    catch( Exception exception )
    070      {
    071      throw new CascadingException( "unable to compare Tuples, likely a CoGroup is being attempted on fields of " +
    072        "different types or custom comparators are incorrectly set on Fields", exception );
    073      }
    074    }
    075  }