import?java.util.ArrayList;
import?java.util.*;

/**
?*?The?class?AudioDatabase?maintains?a?collection?of?AudioFile?objects.This
?*?class?implements?the?interface?Iterable?to?facilitate?iterating
?*?through?the?collection.
?*?
?*?@author?linchen
?*?@version?1.0.0
?*?
?*/
public?class?AudioDatabase?implements?Iterable?{
	private?ArrayList?files;

	/**
	?*?Constructs?a?AudioDatabase?object?which?is?initially
	?*?empty.
	?*/
	public?AudioDatabase（）?{
		this.files?=?new?ArrayList（）;
	}

	/**
	?*?Adds?a?{@link?AudioFile}?object?to?this?AudioFileDatabase.
	?*?
	?*?@param?audioFile
	?*????????????the?{@link?AudioFile}?object.
	?*/

	public?void?addFile（AudioFile?audioFile）?{
		this.files.add（audioFile）;
	}

	/**
	?*?Removes?a?{@link?AudioFile}?object?to?this?AudioFileDatabase.
	?*?
	?*?@param?audioFile
	?*????????????the?{@link?AudioFile}?object.
	?*/
	public?void?removeFile（AudioFile?audioFile）?{
		this.files.remove（audioFile）;
	}

	/**
	?*?Returns?an?iterator?over?the?instances?in?the?collection?files.
	?*?
	?*?
	?*?return?an?{@link?Iterator}?over?the?instances?in?the?collection?files.
	?*/

	public?Iterator?iterator（）?{
		return?this.files.iterator（）;
	}

	/**
	?*?Returns?a?reference?to?the?AudioFile?object?with?the?specified?name.
	?*?Returns?null?if?there?are?no?files?in?the?database?with?the?specified
	?*?name.
	?*?
	?*?@param?name
	?*????????????the?name?of?the?audiofile.
	?*?@return?Returns?a?reference?to?the?AudioFile?object?with?the?specified
	?*?????????name.
	?*/
	public?AudioFile?getFile（String?name）?{
		for?（AudioFile?audioFile?:?this.files）?{
			if?（audioFile.getName（）.equals（name））?{
				return?audioFile;
			}
		}
		return?null;
	}

	/**
	?*?Returns?the?number?of?instances?in?the?collection?files.
	?*?
	?*?@return?Returns?the?number?of?instances?in?the?collection?files.
	?*?
	?*/
	public?int?getNumberOfFiles（）?{
		return?this.files.size（）;
	}

	/**
	?*?Returns?an?array?containing?the?names?of?all?the?files?stored?in?the
	?*?collection?files.
	?*?
	?*?@return?Returns?an?array?containing?the?names?of?all?the?files?stored?in
	?*?????????the?collection?files.
	?*?
	?*/
	public?String[]?getFileNames（）?{
		String[]?fn?=?new?String[this.files.size（）];
		int?i?=?0;
		for?（MediaFile?mediaFile?:?this.files）?{
			fn[i]?=?mediaFile.getName（）;
			i++;
		}
		return?fn;
	}

	/**
	?*?Returns?the?total?duration?（play?time）?of?audio?available?in?the?database
	?*?
	?*?@return?Returns?the?total?duration?（play?time）?of?audio?available?in?the
	?*?????????database
	?*/
	public?int?getDuration（）?{
		int?p?=?0;
		for?（AudioFile?audioFile?:?this.files）?{
			p?+=?audioFile.getDuration（）;
		}
		return?p;
	}
}