Class: JSONP3::LRUCache

Inherits:
Object
  • Object
show all
Defined in:
lib/json_p3/cache.rb

Overview

A least recently used cache relying on Ruby hash insertion order.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(max_size = 128) ⇒ LRUCache

Returns a new instance of LRUCache.


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# File 'lib/json_p3/cache.rb', line 8

def initialize(max_size = 128)
  @data = {}
  @max_size = max_size
end

Instance Attribute Details

#max_size ⇒ Object (readonly)

Returns the value of attribute max_size.


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# File 'lib/json_p3/cache.rb', line 6

def max_size
  @max_size
end

Instance Method Details

#[](key) ⇒ Object

Return the cached value or nil if key does not exist.


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# File 'lib/json_p3/cache.rb', line 14

def [](key)
  val = @data[key]
  return nil if val.nil?

  @data.delete(key)
  @data[key] = val
  val
end

#[]=(key, value) ⇒ Object 


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# File 'lib/json_p3/cache.rb', line 23

def []=(key, value)
  if @data.key?(key)
    @data.delete(key)
  elsif @data.length >= @max_size
    @data.delete((@data.first || raise)[0])
  end
  @data[key] = value
end

#keys ⇒ Object 


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# File 'lib/json_p3/cache.rb', line 36

def keys
  @data.keys
end

#length ⇒ Object 


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# File 'lib/json_p3/cache.rb', line 32

def length
  @data.length
end