// A PlayList has a collection of Tracks. In addition, playlists also have a name
// and a description, Eg. a playlist by the name "MJ All time hits" with the
// description "The greatest tracks by the King of Pop" has a collection of Tracks
// each a song by Michael Jackson.

// An additional feature of your playlist will be that you can search for tracks 
// by title and by artist. These search commands can be one of two types (examples
// below) - 
// 1. Exact Search: 
// searchByExactTitle("Dark Side of the Moon") will return the single Track 
// among all the tracks in this PlayList that have their title as "Dark Side of the
// Moon". If no such track exists, then null is returned.
// 2. Approximate (or Substring) Search
// searchByTitle("moon") will return all the Tracks in this PlayList that have the
// word "moon" in their title. Note that since there can be more than one such
// Track, the return value is a new PlayList with only the correct tracks. For
// example, PlayList p2 = p1.searchByTitle("moon")   then p2 is a playlist
// whose tracks are the tracks that were in p1 and had the word "moon" in their
// name. Note that the chosen tracks will now be present both in playlist p1 and
// p2. The name property of p2, should be the search expression ("moon" in this
// case), and description should indicate that it was a search result ("search for
// for title: moon" in this case).

import java.util.ArrayList;

public class PlayList{
 
  // The instance variables of the PlayList - the name, description, and collection
  // of tracks in the playlist.
  
  
  // The constructor for a playlist... create an empty playlist with the name
  // and description provided
  public PlayList(String playListName, String description){}
  
  // Access methods - get the name, description, tracks, and the number of tracks
  public String getName() { return ""; }
  public String getDescription() { return ""; }
  public ArrayList getTracks() { return null; }
  public int getNumberOfTracks() { return 0; }
  
  // Express the contents of the playlist as a single string - the string should
  // include the name of the playlist, its description and the details of each of
  // the tracks in the playlist. Remember that your string can also include 
  // newlines ("\n") so that the string is more readable. 
  // Note: This method sould NOT print the string, but return the string.
  public String toString() { return ""; }
  
  
  // Commands
  
  // Add a single track to the collection of tracks in this playlist.
  // Check if the parameter is not a null parameter.
  public void addTrack(Track track) {}
  
  
  // Merge two playlists. Add the tracks in the other playlist to the tracks in this
  // playlist. Retain the name and description of this playlist. 
  // Note: You should NOT create a new PlayList. The tracks in the other playlist
  // will now be present in both this and the other playlist.
  public void combinePlayList(PlayList other) {}
  
  
  // Search Methods
   
  // Search for a track in this PlayList whose title exactly matches the 
  // title exactTitle. If there are multiple tracks with that name, return any
  // one. Return null if there is no such track.
  public Track searchByExactTitle(String exactTitle){ return null; }
  
  // Search for the tracks in this PlayList such that titleSubString is a 
  // part of the title of the track. Return a new PlayList that has only
  // the tracks that satisfy this condition. The name and description of the
  // newly created PlayList are as described at the top of this file.
  // Observe that there might not be any tracks which satisfy this search. 
  // In that case the return playlist will have no tracks (but still has a 
  // valid name and description).
  public PlayList searchByTitle(String titleSubString){ return null; }
  
  // Search for the tracks such that artistSubString is a part of the artist name
  // for the track. The rest of the description is similar to that of the 
  // searchByTitle method.
  public PlayList searchByAritist(String artistSubString){ return null; }
  
}