Golang建造者模式对象组装教程

user := User{
    Name:     "Alice",
    Age:      25,
    Email:    "alice@example.com",
    Address:  "",
    Phone:    "",
    IsActive: true,
}

type User struct {
    Name     string
    Age      int
    Email    string
    Address  string
    Phone    string
    IsActive bool
}

type UserBuilder struct {
    user *User
}

func NewUserBuilder() *UserBuilder {
    return &UserBuilder{user: &User{}}
}

func (b *UserBuilder) SetName(name string) *UserBuilder {
    b.user.Name = name
    return b
}

func (b *UserBuilder) SetAge(age int) *UserBuilder {
    b.user.Age = age
    return b
}

func (b *UserBuilder) SetEmail(email string) *UserBuilder {
    b.user.Email = email
    return b
}

func (b *UserBuilder) SetAddress(addr string) *UserBuilder {
    b.user.Address = addr
    return b
}

func (b *UserBuilder) SetPhone(phone string) *UserBuilder {
    b.user.Phone = phone
    return b
}

func (b *UserBuilder) Activate() *UserBuilder {
    b.user.IsActive = true
    return b
}

func (b *UserBuilder) Build() (*User, error) {
    if b.user.Name == "" {
        return nil, fmt.Errorf("name is required")
    }
    if b.user.Email == "" {
        return nil, fmt.Errorf("email is required")
    }
    return b.user, nil
}

user, err := NewUserBuilder().
    SetName("Bob").
    SetAge(30).
    SetEmail("bob@example.com").
    SetPhone("13800138000").
    Activate().
    Build()

if err != nil {
    log.Fatal(err)
}

func NewUserBuilder() *UserBuilder {
    return &UserBuilder{
        user: &User{
            IsActive: true,
            Age:      18,
        },
    }
}

type UserOption func(*UserBuilder)

func WithAddress(addr string) UserOption {
    return func(b *UserBuilder) {
        b.SetAddress(addr)
    }
}

func WithPhone(phone string) UserOption {
    return func(b *UserBuilder) {
        b.SetPhone(phone)
    }
}

// 修改构造函数接受选项
func NewUserBuilderWithOptions(name, email string, opts ...UserOption) (*User, error) {
    builder := NewUserBuilder().SetName(name).SetEmail(email)
    for _, opt := range opts {
        opt(builder)
    }
    return builder.Build()
}

user, err := NewUserBuilderWithOptions(
    "Charlie",
    "charlie@example.com",
    WithAddress("Beijing"),
    WithPhone("13900139000"),
)