package PlaylistForSongs;
import java.util.ArrayList; import java.util.Scanner;
public class Main {
private static ArrayList<Album> listOfAlbums = new ArrayList<>();
private static Scanner scanner = new Scanner(System.in);
public static void main(String[] args) {
Album album = new Album("Fruit du démon", "Soolking");
album.addSong("Milano", 400);
album.addSong("Guerilla", 433);
album.addSong("Dalida", 233);
album.addSong("Liberté", 323);
album.addSong("Zemër", 432);
album.addSong("Espérance", 123);
listOfAlbums.add(album);
album = new Album("Dellali", "Cheb Mami");
album.addSong("Le Raï c'est Chic", 300);
album.addSong("Ana Oualache", 533);
album.addSong("Zarartou", 433);
album.addSong("Khalouni", 423);
album.addSong("Ma Vie 2 Fois", 432);
album.addSong("Machi Chaba", 123);
album.addSong("Chaba", 1223);
listOfAlbums.add(album);
PlayList myFavorite = new PlayList("My favorite", listOfAlbums);
System.out.println("**************************************************************************");
myFavorite.addSong("Machi Chaba");
myFavorite.addSong("Zemër");
myFavorite.addSong("Ana Oualache");
myFavorite.addSong("ntia Machi Chaba");
boolean quit = false;
printChoice();
System.out.print("your choice is: ");
while (!quit) {
int choice = scanner.nextInt();
scanner.nextLine();
switch (choice - 1) {
case 0:
quit = true;
System.out.println("closing the play list ...");
break;
case 1:
myFavorite.playNext();
break;
case 2:
myFavorite.playBackward();
break;
case 3:
myFavorite.replaySong();
break;
case 4:
printChoice();
break;
}
}
}
private static void printAlbums() {
System.out.println("\nAlbums:\n************************");
for (Album a : listOfAlbums) {
System.out.println(a.getName());
}
System.out.println("\n************************");
}
public static void printChoice() {
System.out.println("choices: \n" +
"1- Quit\n" +
"2- Skip forward to the next song\n" +
"3- skip backwards to a previous song.\n" +
"4- Replay the current song.\n" +
"5- Print Choices");
}
}
package PlaylistForSongs;
public class Song {
private String title;
private int duration;
public Song(String title, int duration) {
this.title = title;
this.duration = duration;
}
public String getTitle() {
return title;
}
public String getDuration() {
int hours;
int minutes;
int seconds;
seconds = duration;
minutes = seconds / 60;
seconds %= 60;
if( minutes > 60 ){
hours = minutes / 60;
minutes %= 60;
}else{
hours = 0;
}
return hours + " : " + minutes + " : " + seconds;
}
@Override
public String toString() {
return this.title + ": " + this.getDuration();
}
}
package PlaylistForSongs;
import java.util.ArrayList;
public class Album {
private ArrayList<Song> songsList;
private String name;
private String artist;
private int numberOfSongs;
public Album(String name, String artist) {
this.songsList = new ArrayList<>();
this.name = name;
this.artist = artist;
this.numberOfSongs = 0;
}
public String getName() {
return name;
}
public int getNumberOfSongs() {
return numberOfSongs;
}
public boolean addSong( Song song ){
for ( Song s : this.songsList ) {
if( s.equals(song) ){
System.out.println("The song " + song + " Already exist in the album" + this.name);
return false;
}
}
songsList.add(song);
System.out.println("The song " + song + " added successfully in " + this.name);
this.numberOfSongs ++;
return true;
}
public boolean addSong( String title, int duration){
for( Song s : this.songsList){
if( s.getTitle().equals(title)){
System.out.println("The song " + title + " Already exist in the album" + this.name);
return false;
}
}
songsList.add(new Song(title, duration));
System.out.println("The song " + title + " added successfully in " + this.name);
this.numberOfSongs ++;
return true;
}
public void show(){
System.out.println("\nThe album " + this.name + " has " + this.numberOfSongs + "\nThe songs: ");
for( Song s : this.songsList){
System.out.println(s.toString());
}
}
public Song getSong( String Title){
for( int i = 0; i < songsList.size(); i++){
if(songsList.get(i).getTitle().equals(Title)){
return songsList.get(i);
}
}
System.out.println("the song " + Title + " doesn't exist in album " + this.name + " from album");
return null;
}
public boolean checkSong( String songTitle){
for( int i = 0; i < songsList.size(); i++){
if(songsList.get(i).getTitle().equals(songTitle)){
return true;
}
}
return false;
}
private boolean checkSong( Song song){
for( int i = 0; i < songsList.size(); i++){
if(songsList.get(i).getTitle().equals(song.getTitle())){
return true;
}
}
return false;
}
}
package PlaylistForSongs;
import java.util.*;
public class PlayList {
private String name;
private LinkedList<Song> songsInPlay;
private ArrayList<Album> albumList;
private boolean forward;
private ListIterator<Song> songsInPlayIterator ;
public PlayList(String name, ArrayList<Album> albumList) {
this.name = name;
this.songsInPlay = new LinkedList<>();
this.albumList = albumList;
this.forward = true;
songsInPlayIterator = songsInPlay.listIterator();
}
public void addSong(String title) {
if (findSong(title) != null) {
this.songsInPlay.add(findSong(title));
System.out.println("The song " + title + " has been added successfully to the Play List: " + name);
} else {
System.out.println("we can't add the song " + title + " it doesn't exist in our albums");
}
}
private Song findSong(String songName) {
for (Album album : albumList) {
if( album.checkSong(songName)){
return album.getSong(songName);
}
}
return null;
}
public void playNext(){
if(songsInPlayIterator.hasNext()){
System.out.println("the song: " + songsInPlayIterator.next() + "in play");
this.forward = true;
}
}
public void playBackward(){
if(songsInPlayIterator.hasPrevious() && forward){
songsInPlayIterator.previous();
forward = false;
}
System.out.println("the song: " + songsInPlayIterator.previous() + "in play");
}
public void replaySong(){
if(songsInPlayIterator.hasPrevious() && forward){
System.out.println("the song: " + songsInPlayIterator.previous() + "in play");
forward = false;
}
if (songsInPlayIterator.hasNext() && !forward){
System.out.println("the song: " + songsInPlayIterator.next() + "in play");
forward = true;
}
}
this is the ERROR Exception in thread "main" java.util.ConcurrentModificationException at java.base/java.util.LinkedList$ListItr.checkForComodification(LinkedList.java:970) at java.base/java.util.LinkedList$ListItr.next(LinkedList.java:892) at PlaylistForSongs.PlayList.playNext(PlayList.java:42) at PlaylistForSongs.Main.main(Main.java:52)
In PlayList introduce the statement
songsInPlayIterator = songsInPlay.listIterator();
after lines 40, 47, 55 after doing that i get this result enter image description here
