Java设计模式之模板方法模式

TEMPLATE METHOD （Class Behavioral） 
Purpose 
Identifies the framework of an algorithm, allowing implementing 
classes to define the actual behavior. 
Use When 
1 A single abstract implementation of an algorithm is needed. 
2 Common behavior among subclasses should be localized to a 
  common class. 
3 Parent classes should be able to uniformly invoke behavior in 
   their subclasses. 
4 Most or all subclasses need to implement the behavior. 
Example 
A parent class, InstantMessage, will likely have all the methods 
required to handle sending a message. However, the actual 
serialization of the data to send may vary depending on the 
implementation. A video message and a plain text message 
will require different algorithms in order to serialize the data 
correctly. Subclasses of InstantMessage can provide their 
own implementation of the serialization method, allowing the 
parent class to work with them without understanding their 
implementation details. 

package javaPattern.templateMethod;


abstract class AbstractClass{
    public void templateMethod(){
        subMethod1();
        subMethod2();
    }
    public abstract void subMethod1();
    public abstract void subMethod2();
}
class ConcreteClassA extends AbstractClass{

    @Override
    public void subMethod1() {
        System.out.println("具体类A的方法1");

    }

    @Override
    public void subMethod2() {
        System.out.println("具体类A的方法2");

    }

}
class ConcreteClassB extends AbstractClass{

    @Override
    public void subMethod1() {
        System.out.println("具体类B的方法1");

    }

    @Override
    public void subMethod2() {
        System.out.println("具体类B的方法2");

    }

}
public class TemplateMethod {

    public static void main(String[] args) {
        AbstractClass ac ;
        ac = new ConcreteClassA();
        ac.templateMethod();
        ac = new ConcreteClassB();
        ac.templateMethod();
    }
}