設計模式學習總結2 – 建立型2 – Builder產生器模式

Builder產生器模式(建立型)

作用：

Builder產生器模式將產生複雜物件的具體過程和它的建構函式分離開，同樣的構造過程可以執行個體出不同的對象。

Role
The Builder pattern separates the specification of a complex object from its actual construction. The same construction process can create different representations.

設計：

產生器介面IBuilder，定義要Build哪些內容
執行個體對象控制器Director，包含一系列產生對象的操作
產生器Builder，被執行個體化對象控制器Director調用來執行個體化對象
對象Product，由多部分組成的對象

舉例：
IBuilder   製造鋼筆的一系列規範
Director  使用BuilderA製造鋼筆
BuilderA  某種按IBuilder規範製造鋼筆的方法
Product   由多個零件組成的鋼筆
代碼：

 

代碼

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Builder
{
    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Reflection;

    namespace BuilderExemple
    {
        class Program
        {
            static void Main(string[] args)
            {
                ComputerFactory factory = new ComputerFactory();
                ComputerBuilder office = new OfficeComputerBuilder();
                factory.BuildComputer(office);
                office.Computer.ShowSystemInfo();
                ComputerBuilder game = new GameComputerBuilder();
                factory.BuildComputer(game);
                game.Computer.ShowSystemInfo();
            }
        }

        class ComputerFactory
        {
            public void BuildComputer(ComputerBuilder cb)
            {
                Console.WriteLine();
                Console.WriteLine(">>>>>>>>>>>>>>>>>>Start Building " + cb.Name);
                cb.SetupMainboard();
                cb.SetupCpu();
                cb.SetupMemory();
                cb.SetupHarddisk();
                cb.SetupVideocard();
                Console.WriteLine(">>>>>>>>>>>>>>>>>>Build " + cb.Name + " Completed");
                Console.WriteLine();
            }
        }

        abstract class ComputerBuilder
        {
            protected string name;

            public string Name
            {
                get { return name; }
                set { name = value; }
            }

            protected Computer computer;

            public Computer Computer
            {
                get { return computer; }
                set { computer = value; }
            }

            public ComputerBuilder()
            {
                computer = new Computer();
            }

            public abstract void SetupMainboard();
            public abstract void SetupCpu();
            public abstract void SetupMemory();
            public abstract void SetupHarddisk();
            public abstract void SetupVideocard();
        }

        class OfficeComputerBuilder : ComputerBuilder
        {
            public OfficeComputerBuilder()
            {
                name = "OfficeComputer";
            }

            public override void SetupMainboard()
            {
                computer.Mainboard = "Abit升技 LG-95C 主板 (Intel 945GC晶片集/LGA 775/1066MHz) ";
            }

            public override void SetupCpu()
            {
                computer.Cpu = "Intel 英特爾賽揚D 336 (2.8GHz/LGA 775/256K/533MHz)  ";
            }

            public override void SetupMemory()
            {
                computer.Memory = "Patriot博帝 DDR2 667 512MB 台式機記憶體";
            }

            public override void SetupHarddisk()
            {
                computer.Harddisk = "Hitachi日立 SATAII介面台式機硬碟 (80G/7200轉/8M)盒裝";
            }

            public override void SetupVideocard()
            {
                computer.Videocard = "主板整合";
            }
        }

        class GameComputerBuilder : ComputerBuilder
        {
            public GameComputerBuilder()
            {
                name = "GameComputer";
            }

            public override void SetupMainboard()
            {
                computer.Mainboard = "GIGABYTE技嘉 GA-965P-DS3 3.3 主板(INTEL P965 東莞產)";
            }

            public override void SetupCpu()
            {
                computer.Cpu = "Intel 英特爾酷睿2 E4400 (2.0GHz/LGA 775/2M/800MHz)盒裝";
            }

            public override void SetupMemory()
            {
                computer.Memory = "G.SKILL 芝奇 F2-6400CL5D-2GBNQ DDR2 800 1G*2台式機記憶體";
            }

            public override void SetupHarddisk()
            {
                computer.Harddisk = "Hitachi日立 SATAII介面台式機硬碟 (250G/7200轉/8M)盒裝";
            }

            public override void SetupVideocard()
            {
                computer.Videocard = "七彩虹 逸彩8600GT-GD3 UP烈焰戰神 H10 顯卡 (GeForce 8600GT/256M/DDR3)支援HDMI!";
            }
        }

        class Computer
        {
            private string videocard;

            public string Videocard
            {
                get { return videocard; }
                set { videocard = value; }
            }

            private string cpu;

            public string Cpu
            {
                get { return cpu; }
                set { cpu = value; }
            }

            private string mainboard;

            public string Mainboard
            {
                get { return mainboard; }
                set { mainboard = value; }
            }

            private string memory;

            public string Memory
            {
                get { return memory; }
                set { memory = value; }
            }

            private string harddisk;

            public string Harddisk
            {
                get { return harddisk; }
                set { harddisk = value; }
            }

            public void ShowSystemInfo()
            {
                Console.WriteLine("==================SystemInfo==================");
                Console.WriteLine("CPU:" + cpu);
                Console.WriteLine("MainBoard:" + mainboard);
                Console.WriteLine("Memory:" + memory);
                Console.WriteLine("VideoCard:" + videocard);
                Console.WriteLine("HardDisk:" + harddisk);
                Console.ReadLine();
            }
        }
    }
}

 

使用情境：

建立對象的各個組成部分的演算法是可以分離的；
組合起來的對象可能會有不同的表現
需要控制對象的構造過程

Use the Builder pattern when…
•  The algorithm for creating parts is independent from the parts themselves.
•  The object to be assembled might have different representations.
•  You need fine control over the construction process.

 

總結：

Builder產生器模式是一種建立型模式，它主要是應對項目中一些複雜物件的建立工作。所謂“複雜物件”，是指：此對象中還含有其它的子物件。Builder模式應有的情景：複雜物件的各個部分的子物件可以用一定的演算法構成；由於需求的變化，這個複雜物件的各個部分經常面臨著劇烈的變化，但是將各個部分的子物件組合在一起的演算法卻相對穩定。簡單的說：子物件變化較頻繁，對組合子物件演算法相對穩定。
    這是解決一個複雜物件的建立工作，現在變化的部分和相對穩定的部分已經明確，我們要做的是隔離變化，如何將子物件和演算法隔離是要解決的問題。
    《設計模式》中說道：將一個複雜物件的構建與其表示向分離，使得同樣的構建過程可以建立不同的表示。Builder模式的幾個要點：
    1、用於構建一個複雜的對象，但這個對象構建的演算法是穩定的，對象中的各個部分經常變化。
    2、在於應對複雜物件各個部分的頻繁需求變動。但是難以應對演算法的需求變動。這點一定要注意，如果用複雜物件的內部子物件的組合演算法不穩定，使用Builder會帶來很多不必要的麻煩。