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More importantly, you will learn how to bring all of this knowledge together to demonstrate runtime polymorphism using sound.

This program requires access to the following classes:

  • AudioGraphSinusoidal
  • AudioGraphSquareWave
  • FMSweep
  • MusicComposer08
  • SquareWave
  • StereoPingpong
  • ToneMono
  • TonesStereo
  • WhiteNoise
  • AudioFormatParameters01
  • AudioPlayOrFile01
  • AudioSignalGenerator02

You will find source code for all of these classes in Listing 5 through Listing 16 .

You are already familiar with some of these classes because they were used in earlier modules.

The driver class for this program is the class named MusicComposer08 . That is the only one of the twelve classes that I will discuss in detail. I willleave it as an exercise for the students at this point to study and understand the remaining eleven classes.

Discussion and sample code

The class named MusicComposer08

The purpose of this program is to demonstrate late binding and runtime polymorphism . This is accomplished by using an array of the abstract type AudioSignalGenerator02 populated with references to objects of the following eight classes :

  • AudioGraphSinusoidal
  • AudioGraphSquareWave
  • FMSweep
  • SquareWave
  • StereoPingpong
  • ToneMono
  • TonesStereo
  • WhiteNoise

Each of the classes listed above extends the abstract class named AudioSignalGenerator02 and overrides the inherited abstract method named getMelody .

After the array is populated, a random number generator is used to get a random index into the array. The getMelody method is called on the reference pointed to by the random index. This causes the sound created by that particular audioobject to be played or filed.

This is an example of late binding and runtime polymorphism because the compiler cannot possibly know the value of the random index when the programis compiled.

As in previous modules, the sound can be played immediately or can be saved in an audio file of type AU for playback later. You should be able to play the audio file with anystandard media player that can handle the AU file type.

The program also requires access to the following classes:

  • AudioFormatParameters01
  • AudioPlayOrFile01
  • AudioSignalGenerator02

Beginning of the class named MusicComposer08

Listing 1 shows the beginning of the class named MusicComposer08 . The code in Listing 1 is essentially the same as code that I have explained in several previous modules. Therefore, no further discussion of the code in Listing 1 will be provided in this module.

Listing 1 . Beginning of the class named MusicComposer08.
import java.util.Random; public class MusicComposer08{//Instantiate an object containing audio format parameters with predefined // values. They may be modified by the signal generator at runtime. Values// allowed by Java SDK 1.4.1 are shown in comments in the class definition. AudioFormatParameters01 audioParams = new AudioFormatParameters01();//A buffer to hold the audio data that will be played or filed.byte[] melody;//A place to store the incoming args array. String[]args; //-------------------------------------------------------------------------////Command-line parameter (only one parameter is needed) //If "play", the sound will be played immediately. Otherwise, the string will// be used as a filename for an audio file of type AU. In the latter case, // it must be a string that would be valid as a file name for the operating// system in use. public static void main(String[]args){ //Instantiate a new object of this class.new MusicComposer08(args); }//end main//-------------------------------------------------------------------------//public MusicComposer08(String[] args){//constructor//Save the args array. this.args = args;//Create default args data if no args data is provided on the command line.if(args.length == 0){ this.args = new String[1]; this.args[0]= "play";//Play the melody immediately }//end if

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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