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Using Collections.sort() to sort a list of MP3s

I'm using Collections.sort() to sort a list of MP3s in order of runtime, and if runtime is equal, then sort alphabetically by title, and if title is equal then sort by composer. I put the input into stdin i.e.

Example Input

3
&
Pink Frost&Phillipps, Martin&234933
Se quel guerrier io fossi&Puccini, Giacomo&297539
Non piu andrai&Mozart&234933
M'appari tutt'amor&Flotow, F&252905

But then it doesn't come up with anything via the input. I am confused since it should work perfectly. I don't get any errors.

public class Lab3Algorithm {

public static void main(String args[]) throws IOException {

    List<Song> songs = new ArrayList<Song>();
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    int numOfSongsRequired = Integer.parseInt(br.readLine());
    String sep = br.readLine();

    String line;
    while((line = br.readLine()) != null) {
        String[] fields = sep.split(line);
        songs.add(new Song(fields[0], fields[1], fields[2]));
    }
    Collections.sort(songs);开发者_开发知识库

    System.out.println(songs);
}

}

public class Song implements Comparable<Song> {

private final String title;
private final String composer;
private final int runningTime;

public Song(String title, String composer, String runningTime) {
    this.title = title;
    this.composer = composer;
    this.runningTime = Integer.parseInt(runningTime);
}

public String getTitle(){
    return this.title;
}

public String getComposer(){
    return this.composer;
}

public int getRunningTime(){
    return this.runningTime;
}

@Override
public int compareTo(Song s) {
    if (runningTime > s.runningTime) {
        return 1;
    } else if (runningTime < s.runningTime) {
        return -1;
    }
    int lastCmp = title.compareTo(s.title);
    return (lastCmp != 0 ? lastCmp : composer.compareTo(s.composer));
}
}

If someone could point me in the right direction, that would make me grateful.


String[] fields = sep.split(line); seems wrong - you're not trying to split the separator string on the song input; you want to split the song input on the separator:

String[] fields = line.split(sep);


your while is faulty

for(int i = 0;i<numOfSongsRequired ;i++) {
    line = br.readLine();
    String[] fields = line.split(sep);//line should be splitted by sep btw
    songs.add(new Song(fields[0], fields[1], fields[2]));
}

readline only gives null on if there is a EOF (ctrl-z or ctrl-d depending on the platform)

otherwise it just blocks waiting on the next line

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