tree 48ab341599590d68b8f7f24218fb242014d4c282
parent 400b4876c0613e52ab499e1db69b85069160f29f
author RamanGrover29 <RamanGrover29@123451ca-8445-de46-9d55-352943316053> 1288743703 +0000
committer RamanGrover29 <RamanGrover29@123451ca-8445-de46-9d55-352943316053> 1288743703 +0000

modified HadoopMapper operator to work in two modes :
1) SelfReadMode: The mapper reads the input directly from HDFS instead of receiving it from another specific read operator
2) DependentMode :  The mapper is not anymore a source operator, but requires input to be fed by some other operator ( eg a reducer in case of chained MR jobs )
For operators A & B that  connect using a one-to-one connector, A & B can be fused together to form a single operator. The above change maked HadoopReadOperator redundant.
It is not being deleted here as it is a useful operator for reading from HDFS and could be used in other scenarios. 

Modified AbstractHadoopReadOperator to take as argument in the constructor , the input arity. The input arity was earlier assumed to be 1 for Map and Reduce, but is 
0 for Map in the SelfReadMode. 
Modified Reducer to pass the inputArity to base class constructor

git-svn-id: https://hyracks.googlecode.com/svn/trunk@176 123451ca-8445-de46-9d55-352943316053