File readers inside of Mappers ad Reducers

[Dennis Kubes <nu...@dragonflymc.com>]

How would someone go about reading Map and Sequence file contents in 
Mappers and Reducers?  Is it best to only use the addInputDirectory 
method and find a way to get all of the data one needs by key or is 
there a good way to read file contents inside of map and reduce calls. 

I am not asking about what classes (i.e. MapFile.Reader, etc.)  I want 
to know a consistent way to do it.  Right now I am using a static 
reference in the main class, called by an inner class.  This works well 
on one machine but I don't think it is going to work across nodes.  Here 
is how I have it now:

class x {

  private static MapFile.Reader reader = null;

  public x() {
    reader = new MapFile.Reader...
    create mapreduce job
       setMapperClass(InnerX.class);
    submit job
    close reader.
  }

  class InnerX {
 
    map(WritableComparable key, Writable value, OutputCollector output, 
Reporter reporter) {
      do something with reader...
    }
  }

}

Is there a better way to do this?

Dennis