java/src/main/java/com/music/repository/SongRepository.java

package com.music.repository;

import com.music.model.Song;
import java.util.*;

public class SongRepository {
    private final List<Song> songs = new ArrayList<>();

    public void add(Song song) {
        if (song == null) {
            throw new IllegalArgumentException("歌曲不能为 null");
        }
        if (song.getName() == null || song.getName().trim().isEmpty()) {
            throw new IllegalArgumentException("歌曲名不能为空");
        }
        songs.add(song);
    }

    public void addAll(List<Song> songList) {
        for (Song s : songList) {
            add(s);
        }
    }

    public List<Song> getAll() {
        return Collections.unmodifiableList(songs);
    }

    public int size() {
        return songs.size();
    }

    public void clear() {
        songs.clear();
    }
}