자바 Generic 알아보기

자바의 generic type은 형의 안정성을 보장한다.

package com.java.collection;
 
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
 
class Mountain{
    String name;
    int height;
    
    Mountain(String n, int h){
        this.name=n;
        this.height=h;
    }
    
    public String getName(){
        return this.name;
    }
    
    public int getHeight(){
        return this.height;
    }
    
    public String toString(){
        return this.name + " " + this.height;
    }
}
 
public class SortMountains {
    LinkedList<Mountain> mtn = new LinkedList<Mountain>();
    
    class NameCompare implements Comparator<Mountain>{
        @Override
        public int compare(Mountain one, Mountain two){
            return one.getName().compareTo(two.getName());
        }
    }
    
    class HeightCompare implements Comparator<Mountain>{
        @Override
        public int compare(Mountain one, Mountain two){
            // 양수 내림차순, 음수 올림차순 
            return one.getHeight() - two.getHeight();
        }
    }
    
    public static void main(String [] args){
        new SortMountains().go();
    }
    
    public void go(){
        mtn.add(new Mountain("Longs", 14255));
        mtn.add(new Mountain("Elbert", 14433));
        mtn.add(new Mountain("Maroon", 14156));
        mtn.add(new Mountain("Castle", 14265));
        System.out.println("as entered:\n" + mtn);
        
        NameCompare nc = new NameCompare();
        Collections.sort(mtn, nc);
        System.out.println("by name;\n" + mtn);
        
        HeightCompare hc = new HeightCompare();
        Collections.sort(mtn, hc);
        System.out.println("by height;\n" + mtn);
    }
}