2014-02-19 :-(
_ 午後
1300 コード読んだり
_ 古めかしい世界感がある。「教会旋法」が使われている楽曲１０選 - NAVER まとめ
7年くらい前に友人が「梶浦由記の曲聞いたら教会旋法使ってた」的なことを言っていた。ような気がする
cerbe のことですが
_ [Java][Ruby][マルチスレッド][デザインパターン]Java言語で学ぶデザインパターン入門マルチスレッド編 Read-Write Lock - みんなで読むのはいいけれど、読んでる間は書いちゃだめ
誰かが読んでる間は誰でも読める。けど書けない。
誰も読み書きしていない間に書ける。
Data という名前は Ruby の組み込みクラスかしら。怒られたので名前を変えた。
# coding: utf-8
#
# 『増補改訂版Java言語で学ぶデザインパターン入門マルチスレッド編』 http://www.hyuki.com/dp/dp2.html
#
# Read-Write Lock - みんなで読むのはいいけれど、読んでる間は書いちゃだめ
#
require 'thread'
require 'monitor'
class ReadWriteLock
def initialize()
@lock = Monitor.new()
@cond = @lock.new_cond()
@readingReaders = 0 # (A) 実際に読んでいる最中のスレッドの数
@waitingWriters = 0 # (B) 書くのを待っているスレッドの数
@writingWriters = 0 # (C) 実際に書いている最中のスレッドの数
@preferWriter = true # 書くのを優先するならtrue
end
def readLock()
@lock.synchronize {
while ((@writingWriters > 0) or (@preferWriter and (@waitingWriters > 0)))
@cond.wait()
end
@readingReaders += 1 # (A) 実際に読んでいるスレッドの数を1増やす
}
end
def readUnlock()
@lock.synchronize {
@readingReaders -= 1 # (A) 実際に読んでいるスレッドの数を1減らす
@preferWriter = true
@cond.broadcast()
}
end
def writeLock()
@lock.synchronize {
@waitingWriters += 1 # (B) 書くのを待っているスレッドの数を1増やす
begin
while ((@readingReaders > 0) or (@writingWriters > 0))
@cond.wait()
end
rescue
ensure
@waitingWriters -= 1 # (B) 書くのを待っているスレッドの数を1減らす
end
@writingWriters += 1 # (C) 実際に書いているスレッドの数を1増やす
}
end
def writeUnlock()
@lock.synchronize {
@writingWriters -= 1 # (C) 実際に書いているスレッドの数を1減らす
@preferWriter = false
@cond.broadcast()
}
end
end
class BData
def initialize(size)
@lock = ReadWriteLock.new()
@buffer = Array.new(size)
@buffer.fill('*')
end
def read()
@lock.readLock()
begin
return doRead()
rescue
ensure
@lock.readUnlock()
end
end
def write(c)
@lock.writeLock();
begin
doWrite(c)
rescue
ensure
@lock.writeUnlock()
end
end
def doRead()
newbuf = @buffer.clone()
slowly()
return newbuf
end
# @buffer を埋めるなら fill() すればいいんだけど
# 1 文字ごとに slowly() させるのでループしておく
def doWrite(c)
0.upto(@buffer.length - 1) {|i|
@buffer[i] = c
slowly()
}
end
def slowly()
begin
sleep(0.5)
rescue => ex
puts ex
end
end
end
class WriterThread < Thread
def initialize(data, filler)
@data = data
@filler = filler
@index = 0
@random = Random.new()
block = Proc.new {
begin
while true
c = nextchar()
@data.write(c)
sleep(@random.rand(3))
end
rescue => ex
puts ex
end
}
super(&block)
end
def nextchar()
c = @filler[@index]
@index += 1
if @index >= @filler.length
@index = 0
end
return c
end
end
# Thread.current だと分かりづらいので名前をつける
class ReaderThread < Thread
def initialize(data, n)
@data = data
@name = "reader #{n}"
block = Proc.new {
begin
while true
readbuf = @data.read
puts "#{@name} reads #{readbuf}"
end
rescue => ex
puts ex
end
}
super(&block)
end
end
def main(argv)
th ||= []
data = BData.new(10)
th << ReaderThread.new(data, 0)
th << ReaderThread.new(data, 1)
th << ReaderThread.new(data, 2)
th << ReaderThread.new(data, 3)
th << ReaderThread.new(data, 4)
th << ReaderThread.new(data, 5)
th << WriterThread.new(data, "ABCDEFGHIJKLMNOPQTSTUVWXYZ")
th << WriterThread.new(data, "abcdefghijklmnopqrstuvwxyz")
th.each {|t| t.join() }
end
main(ARGV)
スレッドごとの print は同期できないか
ruby Read-Write-Lock.rb reader 2 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"] reader 5 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"]reader 1 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"] reader 4 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"] reader 3 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"] reader 0 reads ["*", "*", "*", "*", "*", "*", "*", "*", "*", "*"] reader 5 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"] reader 3 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"]reader 1 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"] reader 4 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"] reader 0 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"] reader 2 reads ["A", "A", "A", "A", "A", "A", "A", "A", "A", "A"] reader 5 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 2 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 3 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 0 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 4 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 1 reads ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a"] reader 2 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"] reader 5 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"] reader 1 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"] reader 4 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"]reader 3 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"] reader 0 reads ["B", "B", "B", "B", "B", "B", "B", "B", "B", "B"] reader 0 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"] reader 2 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"] reader 1 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"]reader 5 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"] reader 4 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"] reader 3 reads ["b", "b", "b", "b", "b", "b", "b", "b", "b", "b"] reader 2 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"] reader 5 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"] reader 1 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"]reader 3 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"] reader 4 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"] reader 0 reads ["C", "C", "C", "C", "C", "C", "C", "C", "C", "C"] reader 0 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"] reader 4 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"] reader 1 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"]reader 5 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"] reader 3 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"] reader 2 reads ["c", "c", "c", "c", "c", "c", "c", "c", "c", "c"] reader 4 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"] reader 3 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"]reader 5 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"] reader 1 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"] reader 2 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"] reader 0 reads ["D", "D", "D", "D", "D", "D", "D", "D", "D", "D"]
ライセンス
Copyright (C) 2002,2006 Hiroshi Yuki. http://www.hyuki.com/dp/dp2.html hyuki@hyuki.com This software is provided 'as-is', without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software. Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions: 1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required. 2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software. 3. This notice may not be removed or altered from any source distribution.
参考
『増補改訂版Java言語で学ぶデザインパターン入門マルチスレッド編』
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