Added style #8

08-letterbox/README.md

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+Style #8
+==============================
+
+Constraints:
+
+- The larger problem is decomposed into 'things' that make sense for
+  the problem domain 
+
+- Each 'thing' is a capsule of data that exposes one single procedure,
+  namely the ability to receive and dispatch messages that are sent to
+  it
+
+- Message dispatch can result in sending the message to another capsule
+
+Possible names:
+
+- Letterbox
+- Messaging style
+- Objects
+- Actors

08-letterbox/tf-08.py

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+import sys, re, operator, string
+
+class DataStorageManager():
+    """ Models the contents of the file """
+    _data = ''
+
+    def dispatch(self, message):
+        if message[0] == 'init':
+            return self._init(message[1])
+        elif message[0] == 'words':
+            return self._words()
+        else:
+            raise Exception("Message not understood " + message[0])
+ 
+    def _init(self, path_to_file):
+        f = open(path_to_file)
+        self._data = f.read()
+        f.close()
+        pattern = re.compile('[\W_]+')
+        self._data = pattern.sub(' ', self._data).lower()
+
+    def _words(self):
+        """
+        Returns the list words in storage
+        """
+        data_str = ''.join(self._data)
+        return data_str.split()
+
+
+class StopWordManager():
+    """ Models the stop word filter """
+    _stop_words = []
+
+    def dispatch(self, message):
+        if message[0] == 'init':
+            return self._init()
+        elif message[0] == 'is_stop_word':
+            return self._is_stop_word(message[1])
+        else:
+            raise Exception("Message not understood " + message[0])
+ 
+    def _init(self):
+        f = open('../stop_words.txt')
+        self._stop_words = f.read().split(',')
+        f.close()
+        self._stop_words.extend(list(string.ascii_lowercase))
+
+    def _is_stop_word(self, word):
+        return word in self._stop_words
+
+class WordFrequencyManager():
+    """ Keeps the word frequency data """
+    _word_freqs = {}
+
+    def dispatch(self, message):
+        if message[0] == 'increment_count':
+            return self._increment_count(message[1])
+        elif message[0] == 'sorted':
+            return self._sorted()
+        else:
+            raise Exception("Message not understood " + message[0])
+ 
+    def _increment_count(self, word):
+        if word in self._word_freqs:
+            self._word_freqs[word] += 1
+        else:
+            self._word_freqs[word] = 1
+
+    def _sorted(self):
+        return sorted(self._word_freqs.iteritems(), key=operator.itemgetter(1), reverse=True)
+
+class WordFrequencyController():
+
+    def dispatch(self, message):
+        if message[0] == 'init':
+            return self._init(message[1])
+        elif message[0] == 'run':
+            return self._run()
+        else:
+            raise Exception("Message not understood " + message[0])
+ 
+    def _init(self, path_to_file):
+        self._storage_manager = DataStorageManager()
+        self._stop_word_manager = StopWordManager()
+        self._word_freq_manager = WordFrequencyManager()
+        self._storage_manager.dispatch(['init', path_to_file])
+        self._stop_word_manager.dispatch(['init'])
+
+    def _run(self):
+        for w in self._storage_manager.dispatch(['words']):
+            if not self._stop_word_manager.dispatch(['is_stop_word', w]):
+                self._word_freq_manager.dispatch(['increment_count', w])
+
+        word_freqs = self._word_freq_manager.dispatch(['sorted'])
+        for tf in word_freqs[0:25]:
+            print tf[0], ' - ', tf[1]
+
+#
+# The main function
+#
+wfcontroller = WordFrequencyController()
+wfcontroller.dispatch(['init', sys.argv[1]])
+wfcontroller.dispatch(['run'])
+