简单模拟Comparator-策略设计模式

小咪咪 2022-06-11 01:27 125阅读 0赞

//使一个类本身具备比较性
    //优点：实现此接口的类可以自己重写自己规定比较的内容
    //缺点：因为只有一个方法，一个类只能有一种方式进行比较
    public interface MyComparable<E> {
    	public int compareTo(E e);
    }

public interface MyComparator<T> {
    	int compare(T o1,T o2);
    }

//排序类
    public class DataSort {
    	public static void sort(Object[] objs){
    		for(int i=0;i<objs.length-1;i++){
    			for(int j=i+1;j<objs.length;j++){
    				MyComparable c1=(MyComparable)objs[i];
    				MyComparable c2=(MyComparable)objs[j];
    				if(c1.compareTo(c2)>0){
    					Object temp=objs[i];
    					objs[i]=objs[j];
    					objs[j]=temp;
    				}
    			}
    		}
    	}
    }

//人
    public class Person implements MyComparable<Person>{
    	//实现了MyComparator接口,对年龄进行排序的类
    	private MyComparator comage=new PersonAgeComparator();
    	//实现了MyComparator接口,对体重进行排序的类
    	private MyComparator comweight=new PersonWeightComparator();
    	
    	private int weight;
    	private int age;
    /*	使用这种匿名内部类的方式也可以，但是只能够实现一种方式的排序
     *  因为Person类只有一个compareTo方法
     * public int compareTo(Object e) {
    		return new MyComparator(){
    			public int compare(Object o1, Object o2) {
    				Person p1=(Person)o1;
    				Person p2=(Person)o2;
    				if(p1.age>p2.age) 
    					return 1;
    				else if(p1.age<p2.age)
    					return -1;
    				return 0;
    			}}.compare(this, e);
    	}*/
    	
    	public int compareTo(Person p){
    		//使用这种方式的话只要更改对象然后调用方法即可详细点的
    		//话可以开放外部的一个接口，让外部决定要哪种方式来进行
    		//排序，然后在类内部进行if判断即可，比如一个type属性来决定
    //		return comage.compare(this, p);
    		return comweight.compare(this, p);
    	}
    	public Person(int age,int weight) {
    		super();
    		this.age = age;
    		this.weight=weight;
    	}
    	public int getAge() {
    		return age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    	public int getWeight() {
    		return weight;
    	}
    	public void setWeight(int weight) {
    		this.weight = weight;
    	}
    }

//对Person类的年龄进行排序
    public class PersonAgeComparator implements MyComparator<Person>{
    
    	public int compare(Person o1, Person o2) {
    		if(o1.getAge()>o2.getAge()){
    			return 1;
    		}else if(o1.getAge()<o2.getAge()){
    			return -1;
    		}
    		return 0;
    	}
    }

//对Person类的体重来进行排序
    public class PersonWeightComparator implements MyComparator<Person>{
    
    	public int compare(Person o1, Person o2) {
    		if(o1.getWeight()>o2.getWeight()){
    			return 1;
    		}else if(o1.getWeight()<o2.getWeight()){
    			return -1;
    		}
    		return 0;
    	}
    }

public class Test {
    	public static void main(String[] args) {
    		Person[] ii={new Person(4,10),new Person(7,30),new Person(2,40),new Person(9,35)};
    		DataSort.sort(ii);
    		for(Person p:ii){ 
    			System.out.println(p.getAge()+":"+p.getWeight());
    		}
    	}
    /**
     * 对体重进行排序
     * 运行结果：
     * 4:10
     * 7:30
     * 9:35
     * 9:35
     * 2:40
     */
    }