模板方法

Rust 模板方法模式讲解和代码示例

模版方法是一种行为设计模式，它在基类中定义了一个算法的框架，允许子类在不修改结构的情况下重写算法的特定步骤。

进一步了解模板方法模式

Conceptual Example

main.rs

trait TemplateMethod {
    fn template_method(&self) {
        self.base_operation1();
        self.required_operations1();
        self.base_operation2();
        self.hook1();
        self.required_operations2();
        self.base_operation3();
        self.hook2();
    }

    fn base_operation1(&self) {
        println!("TemplateMethod says: I am doing the bulk of the work");
    }

    fn base_operation2(&self) {
        println!("TemplateMethod says: But I let subclasses override some operations");
    }

    fn base_operation3(&self) {
        println!("TemplateMethod says: But I am doing the bulk of the work anyway");
    }

    fn hook1(&self) {}
    fn hook2(&self) {}

    fn required_operations1(&self);
    fn required_operations2(&self);
}

struct ConcreteStruct1;

impl TemplateMethod for ConcreteStruct1 {
    fn required_operations1(&self) {
        println!("ConcreteStruct1 says: Implemented Operation1")
    }

    fn required_operations2(&self) {
        println!("ConcreteStruct1 says: Implemented Operation2")
    }
}

struct ConcreteStruct2;

impl TemplateMethod for ConcreteStruct2 {
    fn required_operations1(&self) {
        println!("ConcreteStruct2 says: Implemented Operation1")
    }

    fn required_operations2(&self) {
        println!("ConcreteStruct2 says: Implemented Operation2")
    }
}

fn client_code(concrete: impl TemplateMethod) {
    concrete.template_method()
}

fn main() {
    println!("Same client code can work with different concrete implementations:");
    client_code(ConcreteStruct1);
    println!();

    println!("Same client code can work with different concrete implementations:");
    client_code(ConcreteStruct2);
}

Output

Same client code can work with different concrete implementations:
TemplateMethod says: I am doing the bulk of the work
ConcreteStruct1 says: Implemented Operation1
TemplateMethod says: But I let subclasses override some operations
ConcreteStruct1 says: Implemented Operation2
TemplateMethod says: But I am doing the bulk of the work anyway

Same client code can work with different concrete implementations:
TemplateMethod says: I am doing the bulk of the work
ConcreteStruct2 says: Implemented Operation1
TemplateMethod says: But I let subclasses override some operations
ConcreteStruct2 says: Implemented Operation2
TemplateMethod says: But I am doing the bulk of the work anyway

模板方法在其他编程语言中的实现