Plz do in Java
For our third lab, we will write a pair of classes that do not have this limitation: Song and Playlist. Playlist objects store a list of Song objects that can be modified in various ways. Most importantly, the state of a Playlist can be saved and loaded from a text file, so we can keep track of our music collection even after our program stops! Class Diagram:1 0..* 0..1 Song -title: String -artist: String -minutes: int -seconds: int -numPlays: int -IDX TITLE = 0: int -IDX ARTIST = 1: int -IDX LENGTH = 2: int -IDX NUM PLAYS = 3: int +Song(info: String) +Song (other: Song) +getTitle(): String +getArtist(): String +getMinutes(): int +getSeconds(): int +getLength(): String +getNumPlays (): int +incrementPlays (): void +toString(): String Playlist -songs: ArrayList
+Playlist() +Playlist(filename: String) -load(filename: String): void +save(filename: String): void +addSong(song: Song): void +addSong(index: int, song: Song): void +addSongs (filename: String): void +getSong(index: int): Song +numSongs(): int +playSong(index: int): void +remove Song(index: int): Song +toString(): String +favoriteArtist(): String +totalPlaytime(): String Song Class: Each Song has a title, artist, length, and play count. The length is stored in two fields: minutes and seconds. Songs can be constructed from either an info String or another Song object. Info Strings have the following format: ",<artist>,<minutes>:<seconds the numbers on aggregation line indicate that each song belongs to either or playlist. likewise indicates playlist has more songs. values are separated by commas with no spaces. index of value is stored in a static variable. for instance idx_artist stores>", which is the value of the artist field. Optionally, an info String may have a fourth value that specifies the number of times a song has been played: "<title>,<artist>,<minutes>:<seconds>,<numplays>" If this value is absent, initialize numPlays to 0. To illustrate this format, consider the following info String: "Ten Years Gone, Led Zeppelin, 6:31" A Song constructed from this String stores "Ten Years Gone" in the title field, "Led Zeppelin in the artist field, 6 in the minutes field, and 31 in the seconds field. The info String does not have a fourth value, so the object stores O in the numPlays field. Below are descriptions of some methods of the Song class: Song(Song other): This is known as a "copy constructor. It creates a new song that is a copy of an existing Song. That is, it initializes the fields of the new Song to the values stored in the given Song. The utility of this method will become clear when writing the Playlist class. .getLength(): Return the song length in the format of an info String: "<minutes>: <seconds if the number of seconds is less than pad value with a leading zero so it has two digits. easiest way to do this format method string class. use which indicates that should be decimal integer at least increment plays increase numplays by note mutator implies songs are mutable. .tostring return an info values fields. o not include in output. getlength avoid duplicating code. playlist class: each stores reference arraylist songs. we want protect these they can only modified methods order accomplish any song must copied before added or returned from playlist. otherwise calling will have mutable private data. below descriptions construct empty filename file strings. contain for every line and match file. load read strings given name. create add end intended helper addsongs save output tostring contents already exists. addsong copy .addsong index index. .addsongs public version .getsong numsongs playsong removesong remove necessary copy. fields on joining newline characters. terminate character. example contains constructed strings: what miles davis fifth genesis then string: firth favorite artist appears most frequently null. totalplaytime total length all following format:>:<minutes>: <seconds>" The number of minutes and seconds should each be a number between 0 and 59. If the number of hours is 0, use this format instead: "<minutes>: <seconds pad the number of seconds with a leading zero if it is less than hours greater minutes as well. for our third lab we will write pair classes that do not have this limitation: song and playlist. playlist objects store list can be modified in various ways. most importantly state saved loaded from text file so keep track music collection even after program stops diagram:1 string int title="0:" artist="1:" length="2:" num plays="3:" void arrayliststyle=""> +Playlist() +Playlist(filename: String) -load(filename: String): void +save(filename: String): void +addSong(song: Song): void +addSong(index: int, song: Song): void +addSongs (filename: String): void +getSong(index: int): Song +numSongs(): int +playSong(index: int): void +remove Song(index: int): Song +toString(): String +favoriteArtist(): String +totalPlaytime(): String Song Class: Each Song has a title, artist, length, and play count. The length is stored in two fields: minutes and seconds. Songs can be constructed from either an info String or another Song object. Info Strings have the following format: "<title>,<artist>,<minutes>:<seconds the numbers on aggregation line indicate that each song belongs to either or playlist. likewise indicates playlist has more songs. values are separated by commas with no spaces. index of value is stored in a static variable. for instance idx_artist stores>", which is the value of the artist field. Optionally, an info String may have a fourth value that specifies the number of times a song has been played: "<title>,<artist>,<minutes>:<seconds>,<numplays>" If this value is absent, initialize numPlays to 0. To illustrate this format, consider the following info String: "Ten Years Gone, Led Zeppelin, 6:31" A Song constructed from this String stores "Ten Years Gone" in the title field, "Led Zeppelin in the artist field, 6 in the minutes field, and 31 in the seconds field. The info String does not have a fourth value, so the object stores O in the numPlays field. Below are descriptions of some methods of the Song class: Song(Song other): This is known as a "copy constructor. It creates a new song that is a copy of an existing Song. That is, it initializes the fields of the new Song to the values stored in the given Song. The utility of this method will become clear when writing the Playlist class. .getLength(): Return the song length in the format of an info String: "<minutes>: <seconds if the number of seconds is less than pad value with a leading zero so it has two digits. easiest way to do this format method string class. use which indicates that should be decimal integer at least increment plays increase numplays by note mutator implies songs are mutable. .tostring return an info values fields. o not include in output. getlength avoid duplicating code. playlist class: each stores reference arraylist songs. we want protect these they can only modified methods order accomplish any song must copied before added or returned from playlist. otherwise calling will have mutable private data. below descriptions construct empty filename file strings. contain for every line and match file. load read strings given name. create add end intended helper addsongs save output tostring contents already exists. addsong copy .addsong index index. .addsongs public version .getsong numsongs playsong removesong remove necessary copy. fields on joining newline characters. terminate character. example contains constructed strings: what miles davis fifth genesis then string: firth favorite artist appears most frequently null. totalplaytime total length all following format:>:<minutes>: <seconds>" The number of minutes and seconds should each be a number between 0 and 59. If the number of hours is 0, use this format instead: "<minutes>: <seconds pad the number of seconds with a leading zero if it is less than hours greater minutes as well></seconds></minutes></seconds></minutes></seconds></minutes><umplays></seconds></minutes></artist>
