HashSet 를 Collection.sort() 을 이용한 정렬방법

1. SongList.txt (중복데이타)

Pink Moon/Nick Drake/5/80
Somersault/Zero 7/4/84
Shiva Moon/Prem Joshua/6/120
Circles/BT/5/110
Deep Channel/Afro Celts/4/120
Passenger/Headmix/4/100
Listen/Tahiti 80/5/90
Listen/Tahiti 80/5/90
Listen/Tahiti 80/5/90
Circles/BT/5/110

2. Song.java

package test;

class Song implements Comparable<Song> {

String title;
String artist;
String rating;
String bpm;

public int compareTo(Song s) {
return title.compareTo(s.getTitle());
}

Song(String t, String a, String r, String b) {
title = t;
artist = a;
rating = r;
bpm = b;
}

public String getTitle() {

return title;
}

public String getArtist() {
return artist;
}

public String getRating() {
return rating;
}

public String getBpm() {
return bpm;
}

public String toString() {

return title;
}

// 추가된 메소드

public boolean equals(Object aSong) {
Song s = (Song) aSong;
return getTitle().equals(s.getTitle());
}

public int hashCode() {
return title.hashCode();
}

}

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[ 설 명 ]

HashSet 에서 중복을 확인하는 방법은 hashCode() 와 equals() 으로 확인

[참조] Head First Java 책 p595

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3. Jukebox6

package test;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;

public class Jukebox6 {

ArrayList<Song> songList = new ArrayList<Song>();

public static void main(String[] args) {
Jukebox6 jukebox = new Jukebox6();
jukebox.go();

}

public void go() {
getSongs();
System.out.println(songList);
Collections.sort(songList);
System.out.println(songList);

HashSet<Song> songSet = new HashSet<Song>();

songSet.addAll(songList);

System.out.println(songSet);

}

void getSongs(){
try{
File file = new File("./SongListMore.txt");

BufferedReader reader = new BufferedReader(new FileReader(file));
String line = null;
while((line = reader.readLine()) != null){
this.addSong(line);
}
}catch(Exception ex){
ex.printStackTrace();
}

}

void addSong(String lineToParase){
String[] tokens = lineToParase.split("/");
Song nextSong = new Song(tokens[0],tokens[1],"","");
songList.add(nextSong);

}
}