Template Method in Rust
Template Method is a behavioral design pattern that allows you to define a skeleton of an algorithm in a base class and let subclasses override the steps without changing the overall algorithm’s structure.
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
