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。
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
