@Override
    public Path call() throws Exception {
      if (!this.skipDummy && isEmptyPath(this.job, this.path, this.ctx)) {
        return createDummyFileForEmptyPartition(this.path, this.job, this.work.getPathToPartitionInfo().get(this.path),
                this.hiveScratchDir);
      }
      return this.path;
    }
Computes a list of all input paths needed to compute the given MapWork. All aliases
are considered and a merged list of input paths is returned. If any input path points
to an empty table or partition a dummy file in the scratch dir is instead created and
added to the list. This is needed to avoid special casing the operator pipeline for
these cases.

@param job JobConf used to run the job
@param work MapWork encapsulating the info about the task
@param hiveScratchDir The tmp dir used to create dummy files if needed
@param ctx Context object
@return List of paths to process for the given MapWork
@throws Exception
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java