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As explained earlier, a text file containing data for the treble clef must be provided. (Actually, it doesn't matter which clef is represented by the single required text file. It could be data for the bass clef if you want tohear that absent of the treble clef melody. It could even be random notes. However, I will continue to refer to the treble clef and the bass clef as aconvenient way to distinguish between the contents of the two text files.)
If bass data (the optional second text file) is provided, the output audio data will be interlaced in the output melody array so that thebass will be played through the left speaker and the treble will be played through the right speaker.
The code in Listing 7 sets the value for channels to either 2 for stereo or 1 for monaural.
Listing 7 also gets and saves the value of beatsPerSec from the args array. Recall that this value determines how fast or slow the notes will be played. A low value causes the note to be played slowly and ahigher value causes the notes to be played faster.
The code in Listing 8 reads the text file (from the subfolder named Music ) containing the data for the treble clef and saves that data in an ArrayList object in a form that is suitable for processing later. (Hopefully you are familiar with the ArrayList class as a result of your studies of the Collections Framework in general and the module titled Java4040: Purpose of Framework Implementations and Algorithms in particular.)
| Listing 8 . Get and save treble clef note data. |
|---|
try{
trebleClef = new ArrayList();BufferedReader in = new BufferedReader(
new FileReader("Music/" + trebleFileName));String str;
while ((str = in.readLine()) != null) {//Split the input string into multiple substrings using the comma as
// the delimiter and save them in an array object.String[] strArr = str.split(",");//Ignore:
// Blank lines that result in a string with a zero length// Comments that begin with a /
// Lines that begin with a spaceif(strArr[0].length() != 0&&!(strArr[0].substring(0,1).equals("/"))&&!(strArr[0].substring(0,1).equals(" "))){//Add the array to the end of the list.
trebleClef.add(strArr);}//end if}//end while
in.close();//close the input file |
Consider the format of the line of text shown near the end of Listing 30 that reads:
9,A3,C4,E4
To play this note on a piano, the user would press three piano keys simultaneously and hold them down for nine beats.
The code in Listing 8 reads each line of text from the text file and parses it into two or more strings using the comma as a delimiter. The two or morestrings are placed in an array object of type String[] and that object's reference is added to the ArrayList object.
Every line of text that is not ignored will contain at least two items separated by commas. The first item must be a number. This is the amount of time that the note willbe held when it is played. The remaining one or more items specify the piano keys that are to be pressed simultaneously to play that note. Therefore, thearrays that are created from the lines of text in the text file are likely to be of different lengths with the minimum length of two elements. The more complicated themelody, the more likely is the occurrence of arrays with more than two elements.
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