local oo = require "Class"
local Queue = oo.class()

--初始化
function Queue:ctor()
    self.list = {}
    self.map = {}
    self.Count = 0
end

--入队
function Queue:EnQueue( key , value )
    if not key or not value then
        return false
    end
    
    if not self.map[ key ] then
        table.insert(self.list, { key = key , value = value })
        self.Count = self.Count + 1
        self.map[ key ] = true
        return true
    end
    return false
end

--出队
function Queue:DeQueue()
    if self.Count == 0 then
        return nil
    end
    local item = self.list[1]
    table.remove(self.list, 1)
    self.map[ item.key ] = nil
    self.Count = self.Count - 1
    return item
end

--查看
function Queue:Peek()
    if self.Count == 0 then
        return nil
    end
    return self.list[1]
end

--是否存在
function Queue:IsExist( key )
    if self.map[ key ] then
        return true
    end
    return false
end

--获取数量
function Queue:GetCount( key )
    return self.Count
end

return Queue