标签：using cli upd delete div safe tst func pac
最近在看client-go源码，在源码的\tools\caches\store.go文件中有一行代码不得其解(如下标黄内容)，它将一个struct赋值给了一个interface
type Store interface { Add(obj interface{}) error Update(obj interface{}) error Delete(obj interface{}) error List() []interface{} ListKeys() []string Get(obj interface{}) (item interface{}, exists bool, err error) GetByKey(key string) (item interface{}, exists bool, err error) // Replace will delete the contents of the store, using instead the // given list. Store takes ownership of the list, you should not reference // it after calling this function. Replace([]interface{}, string) error Resync() error } type cache struct { // cacheStorage bears the burden of thread safety for the cache cacheStorage ThreadSafeStore // keyFunc is used to make the key for objects stored in and retrieved from items, and // should be deterministic. keyFunc KeyFunc } var _ Store = &cache{}
google搜索后没有得到结果，在stackoverflow上提交了一个问题golang syntax in client-go，很快就得到了回答(老外自由时间果然比较多^^)，“var _ Store = &cache{}”的作用是强制要求cache结构实现Store接口。
做个测试，TestSt实现了TestIf接口中的一个方法write，但由于没有实现read，则其并没有实现TestIf接口
下述代码是可以运行的
package main import "fmt" type TestIf interface { write(w string) read() } type TestSt struct { } func (t *TestSt)write(w string){ fmt.Println("write") } func main() { fmt.Println(111) }
但下述是不可以运行的
package main import "fmt" type TestIf interface { write(w string) read() } type TestSt struct { } func (t *TestSt)write(w string){ fmt.Println("write") }
var _ TestIf=&TestSt{}
func main() {
fmt.Println(111)
}
报出的错误如下：
Cannot use ‘&TestSt{}‘ (type *TestSt) as type TestIf in assignment Type does not implement ‘TestIf‘ as some methods are missing: read() more... (Ctrl+F1)
该语法实际就是实现了某结构必须实现某接口的强制要求
标签：using cli upd delete div safe tst func pac
原文地址：https://www.cnblogs.com/charlieroro/p/11023704.html
