策略模式和自定義排序規則

一、定義Person類模型

package cn.lesson8.statary;

public class Person {
	private int id;
	private String name;
	private int age;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
	}
	
	
}

二、定義接口SortInterface

package cn.lesson8.statary;

import java.util.List;

public interface SortInterface {
	public void sort(List<Person> list);
}

三、實現接口的具體方法UpNameSort

該方法繼承了Comparator接口，實現自定義排序規則。

package cn.lesson8.statary;

import java.util.Collections;
import java.util.Comparator;
import java.util.List;

public class UpNameSort implements SortInterface,Comparator<Person>{

	@Override
	public int compare(Person o1, Person o2) {
		int result=o1.getName().compareTo(o2.getName());
		if(0==result){
			return o1.getId()-o2.getId();	//如果名字相等，按Id排序
		}
		return result;
	}

	@Override
	public void sort(List<Person> list) {
		Collections.sort(list, this); //安裝自定義排序規則進行排序，this代表當前的排序規則
	}
	
}

四、調用環境類Environment

package cn.lesson8.statary;

import java.util.List;

public class Environment {
	private SortInterface sortInterface;
	
	public Environment(SortInterface sortInterface){
		this.sortInterface=sortInterface;
	}
	
	public Environment(){
		
	}

	public void setSortInterface(SortInterface sortInterface) {
		this.sortInterface = sortInterface;
	}
	
	public void sort(List<Person> list){
		this.sortInterface.sort(list); //this代表當前對象調用sortInterface對象的sort（）方法
	}
}

五、測試類Client

package cn.lesson8.statary;

import java.util.ArrayList;
import java.util.List;

public class Client {
	public static void main(String[] args){
		Person p1 = new Person();
		p1.setName("Tom");
		p1.setId(1);
		p1.setAge(20);

		Person p2 = new Person();
		p2.setName("Tonny");
		p2.setId(2);
		p2.setAge(50);

		Person p3 = new Person();
		p3.setName("Tom");
		p3.setId(5);
		p3.setAge(30);

		Person p4 = new Person();
		p4.setName("ABC");
		p4.setId(8);
		p4.setAge(10);

		Person p5 = new Person();
		p5.setName("Xyz");
		p5.setId(9);
		p5.setAge(15);
		
		List<Person> list = new ArrayList<Person>();
		list.add(p1);
		list.add(p2);
		list.add(p3);
		list.add(p4);
		list.add(p5);
		
		Environment env=new Environment();
		UpNameSort uns=new UpNameSort();
		env.setSortInterface(uns);
		env.sort(list);
		
		for(int i=0;i<list.size();i++){
			Person p=list.get(i);
			System.out.println(p.toString());
		}
	}
}