Java implements the Template method pattern pattern
The Template method pattern pattern is a behavior design pattern that defines an algorithm framework and delays the specific steps of the algorithm to subclasses. The Template method pattern pattern defines an abstract class, which contains the skeleton of the algorithm and a series of abstract methods for operation steps. These abstract methods can be implemented by specific subclasses to achieve different implementations of algorithms.
The Template method pattern mode is applicable to the following situations:
1. When multiple classes have similar behavior logic, but the specific implementation steps of each class may be different, the Template method pattern pattern can be used. By placing common behavioral logic in abstract classes, specific implementation steps are deferred to subclasses for implementation.
2. When you want to control the flow of an algorithm and allow subclasses to provide custom implementations for certain steps, you can use the Template method pattern pattern. By defining a skeleton algorithm that includes various steps of the process, but some steps can be rewritten by subclasses.
The benefits of the Template method pattern mode include:
1. It can provide a unified algorithm framework to avoid duplicate code. By placing common behavioral logic in abstract classes, repetitive code writing can be reduced and the maintainability of the code can be improved.
2. Some steps of the algorithm can be flexibly extended and customized. Subclasses can choose to override certain methods of the parent class to achieve custom behavior.
The following is a complete sample code of Java, showing the implementation of the Template method pattern pattern:
//Skeleton of Abstract Class Definition Algorithm
abstract class AbstractClass {
//The Template method pattern defines the skeleton of the algorithm
public final void templateMethod() {
//Call specific operation steps
operation1();
operation2();
operation3();
}
//Operation Step 1, Abstract Method, Implemented by Subclass
abstract protected void operation1();
//Operation Step 2, Abstract Method, Implemented by Subclass
abstract protected void operation2();
//Operation Step 3, Abstract Method, Implemented by Subclass
abstract protected void operation3();
}
//Specific Implementation Class 1
class ConcreteClass1 extends AbstractClass {
@Override
protected void operation1() {
System.out.println("ConcreteClass1 operation1");
}
@Override
protected void operation2() {
System.out.println("ConcreteClass1 operation2");
}
@Override
protected void operation3() {
System.out.println("ConcreteClass1 operation3");
}
}
//Specific Implementation Class 2
class ConcreteClass2 extends AbstractClass {
@Override
protected void operation1() {
System.out.println("ConcreteClass2 operation1");
}
@Override
protected void operation2() {
System.out.println("ConcreteClass2 operation2");
}
@Override
protected void operation3() {
System.out.println("ConcreteClass2 operation3");
}
}
public class Main {
public static void main(String[] args) {
//Create specific implementation class object 1
AbstractClass obj1 = new ConcreteClass1();
//Call Template method pattern
obj1.templateMethod();
//Create specific implementation class object 2
AbstractClass obj2 = new ConcreteClass2();
//Call Template method pattern
obj2.templateMethod();
}
}
In the sample code, the abstract class' AbstractClass' defines the skeleton of the algorithm and includes three operational steps and methods. The specific implementation classes' ConcreteClass1 'and' ConcreteClass2 'inherit from the abstract class and implement their respective operation step logic. In the 'Main' class, we created two objects of specific implementation classes, called the Template method pattern respectively, and implemented the specific implementation of the algorithm.
