Class: CasheDevice::CacheDeviceBase

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/cache.rb

Defined Under Namespace

Classes: CachedData

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(cacheDuration = 26*60, cacheMax = 10) ⇒ CacheDeviceBase

Returns a new instance of CacheDeviceBase.



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# File 'lib/cache.rb', line 13

def initialize(cacheDuration = 26*60, cacheMax=10)
    @cacheDuration = cacheDuration
    @cache = Hash.new
    @cacheLRU = []          # Least Recently Used
    @cacheMax = cacheMax
end

Instance Attribute Details

#cacheDuration ⇒ Object

Returns the value of attribute cacheDuration.



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# File 'lib/cache.rb', line 12

def cacheDuration
  @cacheDuration
end

#cacheMax ⇒ Object

Returns the value of attribute cacheMax.



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# File 'lib/cache.rb', line 12

def cacheMax
  @cacheMax
end

Class Method Details

.read(url) ⇒ Object 



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# File 'lib/cache.rb', line 59

def self.read(url)
    self.instance.read(url)
end

Instance Method Details

#directRead(url) ⇒ Object

Returns : data, key key : key to restore data.

Returns:

  • : data, key key : key to restore data.



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# File 'lib/cache.rb', line 22

def directRead(url)
    raise "Implement directRead method."
end

#read(url) ⇒ Object 



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# File 'lib/cache.rb', line 32

def read(url)
    startTime = Time.now
    cached = @cache[url]
    if cached and cached.expireTime > startTime then
        @cacheLRU.delete(cached)
        @cacheLRU.push(cached)
        data = restoreCache(cached.key)
        $log.debug { "cached %s: Time %f sec" %
                    [self.class.name, (Time.now - startTime).to_f] }
        return data
    end
    if @cacheLRU.size >= @cacheMax then
        oldest = @cacheLRU.shift
        @cache.delete(oldest)
    end
    cached = CachedData.new
    cached.url = url
    cached.expireTime = startTime + @cacheDuration
    data, cached.key = directRead(url)
    @cache[url] = cached
    @cacheLRU.push(cached)
    $log.debug {"direct read %s: Time %f sec" %
                [self.class.name, (Time.now - startTime).to_f] }
    data
end

#restoreCache(key) ⇒ Object

Returns : data restore data from key.

Returns:

  • : data restore data from key.



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# File 'lib/cache.rb', line 28

def restoreCache(key)
    key
end