01. 简单工厂模式
<p>go 语言没有构造函数一说，所以一般会定义NewXXX函数来初始化相关类。<br />
NewXXX 函数返回接口时就是简单工厂模式，也就是说Golang的一般推荐做法就是简单工厂。</p>
<p>在这个simplefactory包中只有API 接口和NewAPI函数为包外可见，封装了实现细节。</p>
<h4>simple.go代码</h4>
<pre><code>package simplefactory
import "fmt"
//API is interface
type API interface {
Say(name string) string
}
//NewAPI return Api instance by type
func NewAPI(t int) API {
if t == 1 {
return &hiAPI{}
} else if t == 2 {
return &helloAPI{}
}
return nil
}
//hiAPI is one of API implement
type hiAPI struct{}
//Say hi to name
func (*hiAPI) Say(name string) string {
return fmt.Sprintf("Hi, %s", name)
}
//HelloAPI is another API implement
type helloAPI struct{}
//Say hello to name
func (*helloAPI) Say(name string) string {
return fmt.Sprintf("Hello, %s", name)
}</code></pre>
<h4>simple_test.go代码</h4>
<pre><code>package simplefactory
import "testing"
//TestType1 test get hiapi with factory
func TestType1(t *testing.T) {
api := NewAPI(1)
s := api.Say("Tom")
if s != "Hi, Tom" {
t.Fatal("Type1 test fail")
}
}
func TestType2(t *testing.T) {
api := NewAPI(2)
s := api.Say("Tom")
if s != "Hello, Tom" {
t.Fatal("Type2 test fail")
}
}</code></pre>