【Java设计模式】构造器模式

【定义】

将构造过程与表示分开，以便于相同的构造过程创建不同的表示。

如果对象的构造过程相对复杂，这样的构造模式会非常有效。

【实例】

我们需要根据需求组装相应的计算机，例如硬盘500G，内存8G，CPU8核等等。

【实现】

定义构造步骤：

interface IBuilder
{
    void BuildBody();
    void InsertWheels();
    void AddHeadlights();
    Product GetVehicle();
}

定义一辆车的构造方法：

class Car implements IBuilder
{
    private Product product = new Product();
    @Override
    public void BuildBody()
    {
        product.Add("This is a body of a Car");
    }
    @Override
    public void InsertWheels()
    {
        product.Add("4 wheels are added");
    }
    @Override
    public void AddHeadlights()
    {
        product.Add("2 Headlights are added");
    }
    @Override
    public Product GetVehicle()
    {
        return product;
    }
}

定义摩托车的构造方法：

// Motorcycle is a ConcreteBuilder
class MotorCycle implements IBuilder
{
    private Product product = new Product();
    @Override
    public void BuildBody()
    {
        product.Add("This is a body of a Motorcycle");
    }
    @Override
    public void InsertWheels()
    {
        product.Add("2 wheels are added");
    }
    @Override
    public void AddHeadlights()
    {
        product.Add("1 Headlights are added");
    }
    @Override
    public Product GetVehicle()
    {
        return product;
    }
}

定义产品：

// "Product"
class Product
{
    // We can use any data structure that you prefer. We have used LinkedList here.
    private LinkedList parts;
    public Product()
    {
        parts = new LinkedList();
    }
    public void Add(String part)
    {
        //Adding parts
        parts.addLast(part);
    }
    public void Show()
    {
        System.out.println("\n Product completed as below :");
        for(int i=0;i

生产商：

// "Director"
class Director
{
    IBuilder myBuilder;
    // A series of steps—for the production
    public void Construct(IBuilder builder)
    {
        myBuilder=builder;
        myBuilder.BuildBody();
        myBuilder.InsertWheels();
        myBuilder.AddHeadlights();
    }
}

测试：