Go设计模式之迭代器模式讲解和代码示例

package main
type Collection interface {
	createIterator() Iterator
}

package main
type UserCollection struct {
	users []*User
}
func (u *UserCollection) createIterator() Iterator {
	return &UserIterator{
		users: u.users,
	}
}

package main
type Iterator interface {
	hasNext() bool
	getNext() *User
}

package main
type UserIterator struct {
	index int
	users []*User
}
func (u *UserIterator) hasNext() bool {
	if u.index < len(u.users) {
		return true
	}
	return false
}
func (u *UserIterator) getNext() *User {
	if u.hasNext() {
		user := u.users[u.index]
		u.index++
		return user
	}
	return nil
}

package main
type User struct {
	name string
	age  int
}

package main
import "fmt"
func main() {
	user1 := &User{
		name: "a",
		age:  30,
	}
	user2 := &User{
		name: "b",
		age:  20,
	}
	UserCollection := &UserCollection{
		users: []*User{user1, user2},
	}
	iterator := UserCollection.createIterator()
	for iterator.hasNext() {
		user := iterator.getNext()
		fmt.Printf("User is %+v \n", user)
	}
}