Add option to not use Janome for Japanese tokenization

examples/training/conllu.py

@@ -29,6 +29,7 @@ import conll17_ud_eval
 import spacy.lang.zh
 
 spacy.lang.zh.Chinese.Defaults.use_jieba = False
+spacy.lang.ja.Chinese.Defaults.use_janome = False
 
 random.seed(0)
 numpy.random.seed(0)

spacy/lang/ja/__init__.py

@@ -35,14 +35,32 @@ class JapaneseTokenizer(object):
     def from_disk(self, path, **exclude):
         return self
 
+class JapaneseCharacterSegmenter(object):
+    def __init__(self, vocab):
+        self.vocab = vocab
+
+    def __call__(self, text):
+        words = []
+        spaces = []
+        doc = self.tokenizer(text)
+        for token in self.tokenizer(text):
+            words.extend(list(token.text))
+            spaces.extend([False]*len(token.text))
+            spaces[-1] = bool(token.whitespace_)
+        return Doc(self.vocab, words=words, spaces=spaces)
+
 
 class JapaneseDefaults(Language.Defaults):
     lex_attr_getters = dict(Language.Defaults.lex_attr_getters)
     lex_attr_getters[LANG] = lambda text: 'ja'
+    use_janome = True
 
     @classmethod
     def create_tokenizer(cls, nlp=None):
+        if cls.use_janome:
             return JapaneseTokenizer(cls, nlp)
+        else:
+            return JapaneseCharacterSegmenter(cls, nlp.vocab)
 
 
 class Japanese(Language):