The document defines several classes that represent different types of multimedia items (Item, CD, DVD) that can be stored in a database. The Item class serves as a superclass and stores basic information like title and playing time. The CD and DVD classes extend Item to store genre-specific attributes. A Database class uses an ArrayList to store Item objects and has methods to add items or print a list of all items.

1. 1
Versi 2.
/**
* The Itemclass represents amulti-mediaitem.
* Informationaboutthe itemisstoredandcan be retrieved.
* Thisclass servesasa superclassformore specificitms.
*
* @author Michael KollingandDavidJ.Barnes
* @version2008.03.30
*/
publicclassItem
{
private Stringtitle;
private intplayingTime;
private booleangotIt;
private Stringcomment;
/**
* Initialisethe fieldsof the item.
* @param theTitle The title of thisitem.
* @param time The runningtime of thisitem.
*/
publicItem(StringtheTitle,inttime)
{
title =theTitle;
playingTime=time;
gotIt= false;
comment= "";
}

2. 2
/**
* Enter a commentforthisitem.
* @param commentThe commentto be entered.
*/
publicvoidsetComment(Stringcomment)
{
this.comment=comment;
}
/**
* @return The commentforthisitem.
*/
publicStringgetComment()
{
returncomment;
}
/**
* Setthe flagindicatingwhetherwe ownthisitem.
* @param ownIttrue if we ownthe item, false otherwise.
*/
publicvoidsetOwn(booleanownIt)
{
gotIt= ownIt;
}
/**
* @return true if we owna copyof thisitem.
*/

3. 3
publicbooleangetOwn()
{
returngotIt;
}
/**
* Printdetailsaboutthisitemtothe textterminal.
*/
publicvoidprint()
{
System.out.print("title:"+ title + " (" + playingTime+" mins)");
if(gotIt) {
System.out.println("*");
} else {
System.out.println();
}
System.out.println(" " + comment);
}
}

4. 4
/**
* The CD class representsaCD object. Informationabout the
* CD is storedandcan be retrieved.
*
* @author Michael KollingandDavidJ.Barnes
* @version2008.03.30
*/
publicclassCD extendsItem
{
private Stringartist;
private intnumberOfTracks;
/**
* Initializethe CD.
* @param theTitle The title of the CD.
* @param theArtistThe artistof the CD.
* @param tracks The numberof tracks on the CD.
* @param time The playingtime of the CD.
*/
publicCD(StringtheTitle,StringtheArtist,inttracks,inttime)
{
super(theTitle,time);
artist= theArtist;
numberOfTracks=tracks;
}
/**
* @return The artistfor thisCD.
*/

5. 5
publicStringgetArtist()
{
returnartist;
}
/**
* @return The numberof tracks on thisCD.
*/
publicintgetNumberOfTracks()
{
returnnumberOfTracks;
}
}

6. 6
/**
* The DVD class representsaDVD object. Informationabout the
* DVD isstoredand can be retrieved.We assume thatwe onlydeal
* withmovie DVDsat thisstage.
*
* @author Michael KollingandDavidJ.Barnes
* @version2008.03.30
*/
publicclassDVDextendsItem
{
private Stringdirector;
/**
* Constructorfor objectsof classDVD
* @param theTitle The title of thisDVD.
* @param theDirectorThe directorof thisDVD.
* @param time The runningtime of the mainfeature.
*/
publicDVD(StringtheTitle,StringtheDirector,inttime)
{
super(theTitle,time);
director= theDirector;
}
/**
* @return The directorforthisDVD.
*/
publicStringgetDirector()
{

7. 7
returndirector;
}
}

8. 8
importjava.util.ArrayList;
/**
* The database class provides afacility tostore entertainment
* itemobjects.A listof all itemscanbe printedtothe
* terminal.
*
* Thisversiondoesnotsave the data to disk,andit doesnot
* provide anysearchfunctions.
*
* @author Michael KollingandDavidJ.Barnes
* @version2008.03.30
*/
publicclassDatabase
{
private ArrayList<Item>items;
/**
* Constructan emptyDatabase.
*/
publicDatabase()
{
items= newArrayList<Item>();
}
/**
* Addan itemto the database.
* @param theItemThe itemtobe added.
*/

9. 9
publicvoidaddItem(ItemtheItem)
{
items.add(theItem);
}
/**
* Printa listof all currentlystoreditemstothe
* textterminal.
*/
publicvoidlist()
{
for(Itemitem:items) {
item.print();
System.out.println(); // emptyline betweenitems
}
}
}