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46 lines
1.0 KiB
Ruby
46 lines
1.0 KiB
Ruby
# Without violating encapsulation, capture and externalize an object's internal
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# state allowing the object to be restored to this state later.
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# The Originator can save and load itself. The Caretaker (the main function in
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# this case) never has to touch the memento objects.
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# This implementation is a bit naive:
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# - saves should be kept in files
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# - Marshal will not always work (singleton methods, bindings, etc..)
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module Originator
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def saves
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@saves ||= {}
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end
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def save(key)
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puts "saving key: #{key}"
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@saves[key] = Marshal.dump self
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end
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def restore(key)
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puts "restoring key: #{key}"
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include_state Marshal.load(@saves[key])
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end
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private
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def include_state(other)
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other.instance_variables.each { |v| instance_variable_set(v, other.instance_variable_get(v)) unless v == '@saves' }
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end
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end
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class Example
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include Originator
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attr_accessor :name, :color
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def initialize(name, color)
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@name, @color = name, color
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end
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end
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# Usage
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example = Example.new('Dave', 'blue')
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example.save :now # => saving key now
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