Hive - Hadoop: The Definitive Guide - page 622

return true ;
}
if ( partial == null ) {
partial = new PartialResult ();
}
partial . sum += value . get ();
partial . count ++;
return true ;
}
public PartialResult terminatePartial () {
return partial ;
}
public boolean merge ( PartialResult other ) {
if ( other == null ) {
return true ;
}
if ( partial == null ) {
partial = new PartialResult ();
}
partial . sum += other . sum ;
partial . count += other . count ;
return true ;
}
public DoubleWritable terminate () {
if ( partial == null ) {
return null ;
}
return new DoubleWritable ( partial . sum / partial . count );
}
}
}