sampleimple.py

# Wneh we can pass FileObject to write
class SampleStorletWithWriter(object):
    def __init__(self, logger):
        self.logger = logger

    def __call__(self, in_md, in_files, out_md_files, params):
        for i in xrange(2):
            out_md_files[i].dumps(in_md[i])

        while True:
            data0 = in_files[0].read(1)
            data1 = in_files[1].read(1)
            if not data0 == '' or data1 == '':
                break
            out_files[0].write(max(data0, data1))
            out_files[0].write(min(data0, data1))

# When we get iterator as its return value
from collections import deque

class SampleStorlet(object):
    def __init__(self, logger):
        self.logger = logger
        self.max_queue = deque()
        self.min_queue = deque()

    def read_next(self, in_files):
        d0 = in_files[0].read()
        d1 = in_files[1].read()
        if d0 == '' or d1 == '':
            raise StopIteration()
        else:
            self.max_queue.append(max(d0, d1))
            self.min_queue.append(min(d0, d1))

    def get_iter(self, queue):
        while True:
            if not queue:
                self.read_next()
                continue
            yield self.queue.popleft()

    def __call__(self, in_md, in_files, params):
        return in_md, [self.get_iter(self.max_queue), self.get_iter(self.min_queue)]