go design patterns

Golang implements design patterns.

Creational pattern

Singleton pattern

Structual design pattern

proxy

The proxy pattern wraps an object to hide some of its characteristics. These characteristics could be the fact that is is a remote object(remote proxy),a very heavy object such as a very big image or the dump of a terabyte database(virtual proxy), or a restrictes access object(protection proxy).

Objectives

• Hide an object behind the proxy so the features can be hidden,restricted and so on
• Provide a new abstraction layer that is easy to work with,and can be changed easily

Decorator

Decrator pattern is useful when woring with legacy code.

Objectives

When you think about extending legacy code without the risk of breaking something,you should think of the decrator first.

Like in a Swiss knife, you have a base type (the frame of the knife),and from there yu unfold its functionalities.

Acceptance criteria 验收标准

• We must have the main interface that all decorators will implement. This interface will be called IngredientAdd,and it will have the AddIngredient() string method.
• We must have a core PizzDecorator type that we will add infredients to.
• We must have an ingredient "onion" implementing the same IngredientAdd interface that will add the string onion to the returned pizza.
• ...

Behavioral Patterns

We will encapsulate behaviors, for example, algorithms in the Stragy pattern or executions in the command pattern.

Strategy design pattern

The Strategy pattern uses different algrithoms to achieve some specific functionality.

These algorithms are hidden behind an interface and they must be interchangeable.

switch inputType{
    case Text:
    return &TextSquare{

    }
    case Image:
    return &Imagequare{
    
    }
    default:
    return nil,errors.New("No strategy impl yet)
}

TextSquare, Imagequare implements an interface PrintStrategyto Print.

在现实当中，字节流的处理就是一种。根据处理的类型，选择具体的处理实现。

Chain of responsibility design pattern

责任链模式