Strategy

public interface Comparable {
    int compareTo(Object o);
}
----------


public interface Comparator {
    int compare(Object o1,Object o2);
}


----------
public class Arrays {
    public static void sort(Comparable[] c){
        Comparable temp;
        for(int i=0;i<c.length;i++){
            for(int j=i+1;j<c.length;j++){
                if(c[i].compareTo(c[j])>0){
                    temp = c[i];
                    c[i] = c[j];
                    c[j] = temp;
                }
            }

        }       
    }
}


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public class Cat implements Comparable{
    private int weight;
    private int height;


    public Cat(int weight, int height) {
        this.weight = weight;
        this.height = height;
    }
    public int getWeight() {
        return weight;
    }
    public void setWeight(int weight) {
        this.weight = weight;
    }
    public int getHeight() {
        return height;
    }
    public void setHeight(int height) {
        this.height = height;
    }
    /*未使用Comparator接口
     * @Override
    public int compareTo(Object o) {
        if(o instanceof Cat ){
            Cat c = (Cat)o;
            if(this.height > c.getHeight())
                return 1;
            if(this.height == c.getHeight())
                return 0;
            if(this.height < c.getHeight())
                return -1;
        }
        return -10;
    }*/
    //使用Comparator接口
    @Override
    public int compareTo(Object o) {
        return new HeightComparator().compare(this, o);
    }
    @Override
    public String toString() {
        return "("+this.height+"|"+this.weight+")";
    }
}


----------
class HeightComparator implements Comparator{

    @Override
    public int compare(Object o1, Object o2) {
        Cat c1=(Cat)o1;
        Cat c2=(Cat)o2;
        if(c1.getHeight() > c2.getHeight())
            return 1;
        if(c1.getHeight() == c2.getHeight())
            return 0;
        if(c1.getHeight() < c2.getHeight())
            return -1;
        return -10;
    }
}


----------
import org.junit.Test;
public class ArraysTest {
 
    @Test
    public void testSort() {
        Cat[] cats = {new Cat(1,1),new Cat(3,3),new Cat(2,2)};
        Arrays.sort(cats);
        for(int i=0;i<cats.length;i++){          
            System.out.print(cats[i]);
        }
    }
}