Grouping objects - Objects First with Java: A Practical Introduction Using BlueJ - page 96

Code 4.1
The MusicOrganizer
class

import java.util.ArrayList;

/**
* A class to hold details of audio files.
*
* @author David J. Barnes and Michael Kölling
* @version 2011.07.31
*/
public class MusicOrganizer
{
// An ArrayList for storing the file names of music files.
private ArrayList<String> files;

/**
* Create a MusicOrganizer
*/
public MusicOrganizer()
{

files = new ArrayList<String>();

}

/**
* Add a file to the collection.
* @param filename The file to be added.
*/
public void addFile(String filename)
{

files.add(filename);

}

/**
* Return the number of files in the collection.
* @return The number of files in the collection.
*/
public int getNumberOfFiles()
{

return files.size();

}

/**
* List a file from the collection.
* @param index The index of the file to be listed.
*/