cache.lua

cache = {}

function cache:new()                -- creates cache class object
    local private = { data = {} }

    local obj = {}

    function obj:put(key, value)    -- cache value with specified name
        private.data[key] = value
    end

    function obj:get(key)           -- get cached value by name or nil
        return private.data[key] or nil
    end

    function obj:remove(key)        -- remove value from cache
        private.data[key] = nil
    end

    function obj:clear()            -- clear cache
        private.data = {}
    end

    function obj:is_present(key)    -- true if value cached, false otherwise
        if private.data[key] then
            return true
        else
            return false
        end
    end

    setmetatable(obj, self)
    self.__index = self
    return obj
end

return cache