第20章 Flyweightパターン : 同じものを共有して無駄をなくす

今回のFlyweightパターンは分かりやすいですね。
factoryにpool作っておいて、同じものを表すオブジェクトはpoolに入っているものを共有するだけです。

注意点は2つ。詳細は省きます。

1. 共有しているものを変更すると、複数箇所に影響が及ぶ
2. 管理されているインスタンスは、ガベージコレクションされない

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今回もオリジナルで。とは言っても『元の文字に空白を一文字追加して新しい文字列とする』だけなので全く大したことないですが。
あとpythonにsynchronizedが無くてちょっとがっかり。threading.Queueとか使うとよさそうです。

実行結果

L o r e m   i p s u m   d o l o r   s i t   a m e t ,   c o n s e c t e t u r   a d i p i s c i n g   e l i t .   P r a e s e n t   d i g n i s s i m   d i g n i s s i m   e r o s ,   a c   c o n d i m e n t u m   o r c i   i n t e r d u m   s e d .   U t   e t   d o l o r   a t   e s t   e l e m e n t u m   p o s u e r e .   M a u r i s   i a c u l i s   e u i s m o d   l a c u s ,   e g e t   d a p i b u s   a u g u e   i n t e r d u m   v i t a e .   D o n e c   i d   c o n g u e   e l i t .   D o n e c   e r o s   d i a m ,   c o n s e c t e t u r   s i t   a m e t   v a r i u s   i d ,   f e r m e n t u m   e g e t   n i s i .   V i v a m u s   l a o r e e t   a u c t o r   m a s s a   e g e t   p o r t t i t o r .   C r a s   a   e s t   a   n i s i   e g e s t a s   s a g i t t i s   e t   s i t   a m e t   p u r u s .   F u s c e   n e c   u l l a m c o r p e r   p u r u s .   N u l l a   f a c i l i s i .   V e s t i b u l u m   i n   o r c i   s e d   n i b h   r u t r u m   v e n e n a t i s . 
 
 P r a e s e n t   f a c i l i s i s ,   n i s l   t i n c i d u n t   m a l e s u a d a   s u s c i p i t ,   d o l o r   u r n a   f a c i l i s i s   d o l o r ,   v i t a e   i a c u l i s   l o r e m   l i b e r o   s e d   r i s u s .   Q u i s q u e   e t   p l a c e r a t   m a u r i s .   I n   e g e t   a d i p i s c i n g   n i b h .   P e l l e n t e s q u e   i m p e r d i e t   u l t r i c i e s   f e l i s ,   q u i s   p o r t t i t o r   a u g u e   v i v e r r a   a t .   C u r a b i t u r   s e d   n i b h   i p s u m .   E t i a m   c o n d i m e n t u m   l e c t u s   i d   m a u r i s   l a o r e e t   e g e t   r u t r u m   n u n c   r h o n c u s .   F u s c e   e g e s t a s   s a g i t t i s   l a c u s ,   s e d   u l l a m c o r p e r   s a p i e n   m o l e s t i e   a .   M a u r i s   o r n a r e   t u r p i s   u t   l i g u l a   f a u c i b u s   e t   p o r t a   e s t   l a o r e e t .   U t   e u   p u r u s   a c   d i a m   v a r i u s   f a u c i b u s   e l e m e n t u m   v i t a e   a u g u e .   N u n c   i d   o d i o   v e l i t ,   v e l   r h o n c u s   n u n c .   S e d   e g e s t a s   t r i s t i q u e   s o l l i c i t u d i n .   I n   v i v e r r a   m a u r i s   a t   i p s u m   v u l p u t a t e   m o l l i s .   D o n e c   l e c t u s   f e l i s ,   r h o n c u s   v e l   e l e i f e n d   s e d ,   f a c i l i s i s   a c c u m s a n   l e c t u s .   P r a e s e n t   n e c   m a g n a   v e l   e s t   g r a v i d a   p r e t i u m   s a g i t t i s   v i t a e   d u i .   S u s p e n d i s s e   p o t e n t i .   C u r a b i t u r   l o b o r t i s   t o r t o r   n e c   e s t   a d i p i s c i n g   l a c i n i a . 
 
 L o r e m   i p s u m   d o l o r   s i t   a m e t ,   c o n s e c t e t u r   a d i p i s c i n g   e l i t .   P e l l e n t e s q u e   f e u g i a t   a u g u e   v e l   m a s s a   v o l u t p a t   f r i n g i l l a .   N u l l a m   m a t t i s   a c c u m s a n   s a p i e n   e t   d i c t u m .   S u s p e n d i s s e   n e c   u r n a   e g e t   n i s i   p e l l e n t e s q u e   s e m p e r   s i t   a m e t   q u i s   v e l i t .   A e n e a n   a c c u m s a n   d i a m   i n   s e m   c o n s e c t e t u r   i d   u l t r i c i e s   d o l o r   l o b o r t i s .   I n   e g e s t a s   s e m   u t   n u n c   c o n v a l l i s   s o d a l e s   i n   u t   t o r t o r .   P r a e s e n t   n e c   m a g n a   n e q u e .   P r a e s e n t   s e m p e r   s a g i t t i s   d o l o r   a   d a p i b u s .   N a m   h e n d r e r i t ,   l o r e m   n e c   f a u c i b u s   v e h i c u l a ,   n u n c   e n i m   i n t e r d u m   s e m ,   n o n   e g e s t a s   s a p i e n   a n t e   e u   l e c t u s .   P e l l e n t e s q u e   h a b i t a n t   m o r b i   t r i s t i q u e   s e n e c t u s   e t   n e t u s   e t   m a l e s u a d a   f a m e s   a c   t u r p i s   e g e s t a s .   D u i s   v e l   m a u r i s   t e l l u s ,   e g e t   p l a c e r a t   m i .   P e l l e n t e s q u e   m e t u s   m i ,   e l e i f e n d   u t   t e m p u s   i n ,   f e r m e n t u m   q u i s   l i g u l a .   A l i q u a m   e r a t   l e o ,   m o l l i s   a c   c u r s u s   a c ,   f e u g i a t   i n   n i s i .   E t i a m   g r a v i d a   e u i s m o d   l e c t u s   e t   c o n s e c t e t u r .   E t i a m   i a c u l i s   e l e m e n t u m   r i s u s ,   i n   e l e i f e n d   v e l i t   a u c t o r   a c .   V i v a m u s   u l l a m c o r p e r ,   l o r e m   n o n   m o l e s t i e   c o n v a l l i s ,   t e l l u s   a n t e   p u l v i n a r   s a p i e n ,   v e l   p o r t t i t o r   m a s s a   o d i o   e u   l e c t u s .   D o n e c   a c   r i s u s   t r i s t i q u e   n i s l   e u i s m o d   c o n s e c t e t u r .   D o n e c   m o l l i s   s e m p e r   a n t e ,   q u i s   f e u g i a t   l a c u s   i m p e r d i e t   a t .   N a m   e u   l o r e m   s i t   a m e t   v e l i t   s a g i t t i s   c o n s e c t e t u r   a   v o l u t p a t   m i .   S u s p e n d i s s e   s e d   a d i p i s c i n g   l e c t u s . 
 
 C l a s s   a p t e n t   t a c i t i   s o c i o s q u   a d   l i t o r a   t o r q u e n t   p e r   c o n u b i a   n o s t r a ,   p e r   i n c e p t o s   h i m e n a e o s .   N a m   c o n v a l l i s   f e r m e n t u m   e n i m ,   v e l   b l a n d i t   n i s l   b l a n d i t   v e l .   I n t e g e r   a c   j u s t o   n u l l a .   N u l l a   e r o s   e l i t ,   u l l a m c o r p e r   s e d   c o n d i m e n t u m   v e l ,   p o r t a   s e d   e n i m .   S e d   a t   l i b e r o   v e l   l a c u s   p r e t i u m   d i c t u m .   M a u r i s   h e n d r e r i t   u r n a   s i t   a m e t   m i   r h o n c u s   n o n   a l i q u a m   e n i m   i m p e r d i e t .   C u r a b i t u r   a   e r o s   a   d i a m   u l l a m c o r p e r   r h o n c u s .   P r o i n   e t   m a g n a   i n   n i s i   e l e m e n t u m   d i c t u m   v e l   s i t   a m e t   l e c t u s .   U t   t r i s t i q u e   d u i   q u i s   v e l i t   a u c t o r   m o l e s t i e   d a p i b u s   n u l l a   v a r i u s .   F u s c e   v i t a e   v e l i t   p e l l e n t e s q u e   m a g n a   c o n s e q u a t   p l a c e r a t .   M a e c e n a s   d i g n i s s i m   r i s u s   n o n   e s t   s o l l i c i t u d i n   v u l p u t a t e .   M a u r i s   v i t a e   o r c i   f r i n g i l l a   n u l l a   p r e t i u m   p h a r e t r a .   C u r a b i t u r   a c   f a c i l i s i s   t o r t o r .   C u r a b i t u r   e g e t   m o l l i s   v e l i t .   I n   a c   l e c t u s   e l i t ,   a c   p o s u e r e   r i s u s .   Q u i s q u e   q u i s   l i g u l a   m e t u s ,   u t   b l a n d i t   l i b e r o .   C u r a b i t u r   s e d   n i b h   v i t a e   m i   e l e m e n t u m   m o l e s t i e .   D o n e c   e u i s m o d   a r c u   u t   t u r p i s   u l t r i c e s   v i v e r r a .   N u l l a   f a c i l i s i . 
 
 N u l l a   i d   p u l v i n a r   m a u r i s .   N u n c   m a t t i s   f a c i l i s i s   a u g u e ,   s e d   t r i s t i q u e   e s t   i n t e r d u m   s e d .   P r a e s e n t   u l t r i c i e s   n i b h   i d   a u g u e   s u s c i p i t   i d   u l t r i c i e s   m e t u s   a d i p i s c i n g .   A l i q u a m   e r a t   v o l u t p a t .   V e s t i b u l u m   u t   i p s u m   i n   u r n a   l o b o r t i s   f e u g i a t   v i t a e   s i t   a m e t   a r c u .   A l i q u a m   d i a m   p u r u s ,   p r e t i u m   n e c   c o n s e q u a t   v e l ,   p l a c e r a t   a   n i b h .   A e n e a n   l e o   n i s l ,   u l l a m c o r p e r   i n   p l a c e r a t   c o n g u e ,   m o l e s t i e   u l t r i c e s   t o r t o r .   P r a e s e n t   d i a m   l i g u l a ,   e g e s t a s   a   f e r m e n t u m   s e d ,   u l t r i c i e s   i d   o d i o .   D o n e c   a t   p u r u s   i p s u m .   P h a s e l l u s   p o r t a   p l a c e r a t   s c e l e r i s q u e .   S u s p e n d i s s e   h e n d r e r i t   r u t r u m   q u a m   u t   p o r t t i t o r . 

ソースコード

#!/usr/bin/env python
# -*- coding: utf8 -*-

import sys

# Flyweight class
class SparseChar:
    def __init__(self, char):
        self.__char = char[0]

    def draw(self):
        sys.stdout.write(self.__char+" ")

# FlyweightFactory class
class SparseCharFactory:
    def __init__(self):
        self.__pool = {}

    def getSparseChar(self, char):
        if not self.__pool.has_key(char):
            self.__pool[char] = SparseChar(char)
        return self.__pool[char]

# Client class
class SparseString:
    def __init__(self, string):
        self.__string = string
        self.factory = SparseCharFactory()

    def draw(self):
        for s in self.__string:
            self.factory.getSparseChar(s).draw()
        print ""


def main():
    m_sparseString = SparseString("""Lorem ipsum dolor sit amet, consectetur adipiscing elit. Praesent dignissim dignissim eros, ac condimentum orci interdum sed. Ut et dolor at est elementum posuere. Mauris iaculis euismod lacus, eget dapibus augue interdum vitae. Donec id congue elit. Donec eros diam, consectetur sit amet varius id, fermentum eget nisi. Vivamus laoreet auctor massa eget porttitor. Cras a est a nisi egestas sagittis et sit amet purus. Fusce nec ullamcorper purus. Nulla facilisi. Vestibulum in orci sed nibh rutrum venenatis.

Praesent facilisis, nisl tincidunt malesuada suscipit, dolor urna facilisis dolor, vitae iaculis lorem libero sed risus. Quisque et placerat mauris. In eget adipiscing nibh. Pellentesque imperdiet ultricies felis, quis porttitor augue viverra at. Curabitur sed nibh ipsum. Etiam condimentum lectus id mauris laoreet eget rutrum nunc rhoncus. Fusce egestas sagittis lacus, sed ullamcorper sapien molestie a. Mauris ornare turpis ut ligula faucibus et porta est laoreet. Ut eu purus ac diam varius faucibus elementum vitae augue. Nunc id odio velit, vel rhoncus nunc. Sed egestas tristique sollicitudin. In viverra mauris at ipsum vulputate mollis. Donec lectus felis, rhoncus vel eleifend sed, facilisis accumsan lectus. Praesent nec magna vel est gravida pretium sagittis vitae dui. Suspendisse potenti. Curabitur lobortis tortor nec est adipiscing lacinia.

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Pellentesque feugiat augue vel massa volutpat fringilla. Nullam mattis accumsan sapien et dictum. Suspendisse nec urna eget nisi pellentesque semper sit amet quis velit. Aenean accumsan diam in sem consectetur id ultricies dolor lobortis. In egestas sem ut nunc convallis sodales in ut tortor. Praesent nec magna neque. Praesent semper sagittis dolor a dapibus. Nam hendrerit, lorem nec faucibus vehicula, nunc enim interdum sem, non egestas sapien ante eu lectus. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Duis vel mauris tellus, eget placerat mi. Pellentesque metus mi, eleifend ut tempus in, fermentum quis ligula. Aliquam erat leo, mollis ac cursus ac, feugiat in nisi. Etiam gravida euismod lectus et consectetur. Etiam iaculis elementum risus, in eleifend velit auctor ac. Vivamus ullamcorper, lorem non molestie convallis, tellus ante pulvinar sapien, vel porttitor massa odio eu lectus. Donec ac risus tristique nisl euismod consectetur. Donec mollis semper ante, quis feugiat lacus imperdiet at. Nam eu lorem sit amet velit sagittis consectetur a volutpat mi. Suspendisse sed adipiscing lectus.

Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nam convallis fermentum enim, vel blandit nisl blandit vel. Integer ac justo nulla. Nulla eros elit, ullamcorper sed condimentum vel, porta sed enim. Sed at libero vel lacus pretium dictum. Mauris hendrerit urna sit amet mi rhoncus non aliquam enim imperdiet. Curabitur a eros a diam ullamcorper rhoncus. Proin et magna in nisi elementum dictum vel sit amet lectus. Ut tristique dui quis velit auctor molestie dapibus nulla varius. Fusce vitae velit pellentesque magna consequat placerat. Maecenas dignissim risus non est sollicitudin vulputate. Mauris vitae orci fringilla nulla pretium pharetra. Curabitur ac facilisis tortor. Curabitur eget mollis velit. In ac lectus elit, ac posuere risus. Quisque quis ligula metus, ut blandit libero. Curabitur sed nibh vitae mi elementum molestie. Donec euismod arcu ut turpis ultrices viverra. Nulla facilisi.

Nulla id pulvinar mauris. Nunc mattis facilisis augue, sed tristique est interdum sed. Praesent ultricies nibh id augue suscipit id ultricies metus adipiscing. Aliquam erat volutpat. Vestibulum ut ipsum in urna lobortis feugiat vitae sit amet arcu. Aliquam diam purus, pretium nec consequat vel, placerat a nibh. Aenean leo nisl, ullamcorper in placerat congue, molestie ultrices tortor. Praesent diam ligula, egestas a fermentum sed, ultricies id odio. Donec at purus ipsum. Phasellus porta placerat scelerisque. Suspendisse hendrerit rutrum quam ut porttitor.""")
    m_sparseString.draw()


if __name__=='__main__': main()