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105 lines
3.5 KiB
105 lines
3.5 KiB
from cppy.cp_util import *
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'''
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订阅者 = 注册者 = 观察者
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注册回调的一个变体
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要点是：中心化、统一化
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为了简化消息订阅可能形成的复杂性，
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提供一个中心消息管理器统一负责消息的订阅和回调
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各个功能组件只是完成自己的功能，
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在中心管理器上订阅消息挂到自己响应的处理函数上
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总结，相比较的改变：
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- 注册的时候，通过提供一个类型字段标识不同消息
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- 其它实体不做注册和做回调，统一这两个功能到一个中心单元
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这是一个示例性质的原型，具体分布式环境下需要调整
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'''
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from collections import defaultdict
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#################################################
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# Event Manager
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#################################################
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class EventManager:
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def __init__(self):
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self._subs = defaultdict(list)
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def subscribe(self, event_type, handler):
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self._subs[event_type].append(handler)
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def publish(self, event):
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event_type = event[0]
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for handle in self._subs.get(event_type, []):
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handle(event)
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#################################################
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# Application Entities
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#################################################
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class DataStorage:
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def __init__(self, event_manager):
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self._event_manager = event_manager
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self._event_manager.subscribe('load', self._load)
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self._event_manager.subscribe('start', self.produce_words)
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def _load(self, event):
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self._data = extract_file_words( event[1] )
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def produce_words(self, _):
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for word in self._data:
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self._event_manager.publish(('word', word ))
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self._event_manager.publish(('eof', None))
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class StopWordFilter:
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def __init__(self, event_manager):
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self._event_manager = event_manager
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self._event_manager.subscribe('load', self.load_stop_words)
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self._event_manager.subscribe('word', self.filter_word)
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self._stop_words = set()
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def load_stop_words(self, _ ):
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self._stop_words = set( get_stopwords() )
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def filter_word(self, event):
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word = event[1]
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if word not in self._stop_words:
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self._event_manager.publish(('valid_word', word))
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class WordFrequencyCounter:
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def __init__(self, event_manager):
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self._event_manager = event_manager
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self._event_manager.subscribe('valid_word', self.count_word)
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self._event_manager.subscribe('print', self.print_freqs)
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self._word_freqs = {}
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def count_word(self, event):
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word = event[1]
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self._word_freqs[word] = self._word_freqs.get(word, 0) + 1
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def print_freqs(self, _ ):
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print_word_freqs ( sort_dict (self._word_freqs) )
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class WordFrequencyApp:
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def __init__(self, event_manager):
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self._event_manager = event_manager
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self._event_manager.subscribe('run', self.start_application)
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self._event_manager.subscribe('eof', self.stop_application)
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def start_application(self, event):
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path_to_file = event[1]
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self._event_manager.publish(('load', path_to_file))
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self._event_manager.publish(('start', ))
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def stop_application(self, _ ):
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self._event_manager.publish(('print', ))
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def main():
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event_manager = EventManager()
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DataStorage( event_manager )
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StopWordFilter( event_manager )
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WordFrequencyCounter( event_manager )
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WordFrequencyApp( event_manager )
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event_manager.publish(('run', testfilepath ))
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if __name__ == "__main__":
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main() |