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The instance variable named melody will ultimately refer to an array object that holds the audio data that will be played or filed.

The instance variable named args will ultimately refer to an array object that holds an incoming command-line parameter.

Command-line parameters

Only one command-line parameter is needed and it is optional. If the value of the parameter is "play", the sound will be played immediately. Otherwise, theparameter string will be used as a filename for an audio file of type AU. In this case,it must be a string that would be valid as a file name for your operating system.

The main method

The main method simply instantiates a new object of this class passing the incoming args array's reference to the constructor.

Compiling and executing the program

I typically use Windows batch files to compile and execute my Java program. Listing 2 shows the contents of such a batch file. This batch file will attempt to:

  • Delete all class files in the folder.
  • Delete a file named WhiteNoise.au if it exists.
  • Compile the program.
  • Execute the program once to play the sound immediately.
  • Execute the program again to write the sound to the audio file named WhiteNoise.au.
  • Delete all the class files in the folder.
Listing 2 . The file named WhiteNoise.bat.
echo off del *.classdel WhiteNoise.au echo onjavac MusicComposer04.java java MusicComposer04 playjava MusicComposer04 WhiteNoise echo offdel *.class pause

The constructor for MusicComposer04

Listing 3 shows the beginning of the constructor for MusicComposer04 .

Listing 3 . Beginning of the constructor for MusicComposer04.
public MusicComposer04(String[] args){//constructorthis.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

The constructor begins by saving the incoming reference to the args array containing the command-line parameter.

If the length of the args array is zero, this means that the user did not enter a command-line parameter. In that case, the constructor instantiates an appropriate arrayobject, populates its only element with a reference to a "play" string, and saves that array object's reference in the instance variable discussed earlier .

Get and play or file the sound

Listing 4 instantiates a new object of the WhiteNoise class and saves the object's reference in a local reference variable of type WhiteNoise named whiteNoise . You are already familiar with the three parameters that are passed to the constructor for the WhiteNoise class.

(Later when we discuss runtime polymorphism, we will save such an object's reference in a reference variable of type AudioSignalGenerator02 , which is the immediate superclass of the WhiteNoise class.)

Listing 4 . Get and play or file the sound.
//Get a populated array containing audio data for white or pink noise. WhiteNoise whiteNoise = new WhiteNoise(audioParams,this.args,melody);melody = whiteNoise.getMelody(); //Play or file the audio datanew AudioPlayOrFile01(audioParams,melody,this.args[0]).playOrFileData();}//end constructor //-------------------------------------------------------------------------//}//end class MusicComposer04.java

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
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.
Bharti
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
Daniel
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
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
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
NANO
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
s.
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.
Tarell
what is the actual application of fullerenes nowadays?
Damian
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.
Tarell
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.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
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.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
SUYASH Reply
for screen printed electrodes ?
SUYASH
What is lattice structure?
s. Reply
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
I'm interested in nanotube
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how did you get the value of 2000N.What calculations are needed to arrive at it
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Source:  OpenStax, Accessible objected-oriented programming concepts for blind students using java. OpenStax CNX. Sep 01, 2014 Download for free at https://legacy.cnx.org/content/col11349/1.17
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