CodePattern/15 工程化/松耦合/消息驱动的组件/2 仅有消息接口.py

''' 
依靠给各个不同线程组件的队列发指令来驱动所有工作，比较繁琐。
比较 01.py 的实现，各个组件完全不能互操作，仅依靠队列发消息进行协作
这是一个示例性质的原型，具体分布式环境下需要调整
'''

from threading import Thread
from queue import Queue
from cppy.cp_util import *

class ActiveWFObject(Thread):
    def __init__(self):
        super().__init__()
        self.queue = Queue()
        self._stopMe = False
        self.start()

    def run(self):
        while not self._stopMe:
            message = self.queue.get()
            self._dispatch(message)
            if message[0] == 'over':
                break

def send(receiver, message):
    receiver.queue.put(message)

class DataStorageManager(ActiveWFObject):
    """ Models the contents of the file """
    _data = ''

    def _dispatch(self, message):
        if message[0] == 'init':
            self._init(message[1:])
        elif message[0] == 'send_word_freqs':
            self._process_words(message[1:])
        else:
            # forward
            send(self._stop_word_manager, message)
 
    def _init(self, message):
        self._data = extract_file_words(message[0])
        self._stop_word_manager = message[1]            

    def _process_words(self, message):
        recipient = message[0]        
        for w in self._data:
            send(self._stop_word_manager, ['filter', w])
        send(self._stop_word_manager, ['topWord', recipient])

class StopWordManager(ActiveWFObject):
    """ Models the stop word filter """
    _stop_words = []

    def _dispatch(self, message):
        if message[0] == 'init':
            self._init(message[1:])
        elif message[0] == 'filter':
            return self._filter(message[1:])
        else:
            # forward
            send(self._word_freqs_manager, message)
 
    def _init(self, message):        
        self._stop_words = get_stopwords()
        self._word_freqs_manager = message[0]

    def _filter(self, message):
        word = message[0]
        if word not in self._stop_words:
            send(self._word_freqs_manager, ['word', word])

class WordFrequencyManager(ActiveWFObject):
    """ Keeps the word frequency data """
    _word_freqs = {}

    def _dispatch(self, message):
        if message[0] == 'word':
            self._increment_count(message[1:])
        elif message[0] == 'topWord':
            self._topWord(message[1:])
 
    def _increment_count(self, message):
        word, = message
        self._word_freqs[word] = self._word_freqs.get(word, 0) + 1

    def _topWord(self, message):
        recipient = message[0]
        freqs_sorted = sort_dict ( self._word_freqs )
        send(recipient, ['topWord', freqs_sorted])

class MyController(ActiveWFObject):

    def _dispatch(self, message):
        if message[0] == 'run':
            self._run(message[1:])
        elif message[0] == 'topWord':
            self._display(message[1:])
        else:
            raise Exception("Message not understood " + message[0])
 
    def _run(self, message):
        self._storage_manager, = message
        send(self._storage_manager, ['send_word_freqs', self])

    def _display(self, message):
        word_freqs, = message
        print_word_freqs( word_freqs)        
        send(self._storage_manager, ['over'])
        self._stopMe = True


if __name__ == '__main__':    
    word_freq_manager = WordFrequencyManager()
    stop_word_manager = StopWordManager()
    storage_manager = DataStorageManager()
    wfcontroller = MyController()

    send(storage_manager, ['init', testfilepath, stop_word_manager])
    send(stop_word_manager, ['init', word_freq_manager])        
    send(wfcontroller, ['run', storage_manager])

    # 等待所有管理器完成工作
    threads = [word_freq_manager, stop_word_manager, storage_manager, wfcontroller]
    for thread in threads:  thread.join()