How to create an interface

Question

Sorry for the newbie question. I was provided a class, and they said that in order to use this class the interface can just construct a new SampleClass and method1() followed by method2(). I've looked over the documentation on interfaces, but I still don't get it. I was hoping someone could give me some guidance as to how to use method1() and method2() in my class.
The SampleClass starts off like this
public class SampleClass extends java.io.File {
public boolean method1 {
return true;
public void method2 {
sample.start();
} //my class
public class MyProgram {
public static void main(String args[]) {
}}Thanks in advance for the help!

Answer 1

Ok. Here's the actual program that was given to me. When I do AudioFile af = new AudioFile();. It says that it's unable to resolve. So when I asked the guy about this, he said that I need to use an interface.....again sorry for my confusion.
import java.io.*;
import javax.media.*;
import java.net.*;
import java.util.Vector;
import javax.media.format.AudioFormat;
import javax.media.protocol.DataSource;
import javax.media.protocol.FileTypeDescriptor;
import javax.media.datasink.*;
import javax.media.MediaLocator;
import java.text.DecimalFormat;
import javax.media.control.BufferControl;
public class AudioFile extends java.io.File
private Processor processor;
private CaptureDeviceInfo device;
private DataSink filewriter;
private String audioFormat;
private Player player;
private Time currentMediaTime;
boolean clipSaved;
public AudioFile(String fileName)
super(fileName);
processor = null;
player = null;
device = null;
filewriter = null;
clipSaved = false;
public AudioFile(String path, String name)
this(path + name);
public class StateHandler implements ControllerListener
Processor processor = null;
boolean configured = false;
boolean realized = false;
boolean failed = false;
public StateHandler(Processor p)
processor = p;
p.addControllerListener(this);
public boolean configured(int waitTime)
long startTime =
System.currentTimeMillis();
synchronized(this)
processor.configure();
while(!configured && !
failed)
try
wait
(waitTime);
catch
(InterruptedException ie)
System.out.println("Interrupted configure");
if
(System.currentTimeMillis() - startTime>waitTime)
break;
return configured;
public boolean realized(int waitTime)
long startTime =
System.currentTimeMillis();
synchronized(this)
processor.realize();
while(!realized &&!
failed)
try
wait
(waitTime);
catch
(InterruptedException ie)
System.out.println("Interrupted realize");
if
(System.currentTimeMillis()-startTime>waitTime)
break;
return realized;
public synchronized void controllerUpdate
(ControllerEvent cEvent)
if(cEvent instanceof
RealizeCompleteEvent)
realized=true;
else
if(cEvent instanceof
ConfigureCompleteEvent)
configured=true;
else
return;
notifyAll();
public boolean isClipSaved()
return clipSaved;
public class sinkEventHandler implements
DataSinkListener
DataSinkEvent dsEvent = new DataSinkEvent
(filewriter);
public void dataSinkUpdate(DataSinkEvent
dsEvent)
if(dsEvent instanceof
EndOfStreamEvent)
{ filewriter.close();
System.out.println
("Stream end");
processor.deallocate();
public boolean prepareToPlay()
try
if (player !=null) //if there was a dead player
player.close();
//change file to URL
String fileString = "file:///" +
this.getPath();
player =
Manager.createRealizedPlayer(new MediaLocator(fileString));
if (player == null)
System.out.println("No player");
return false;
else
System.out.println
("Player created");
return true;
catch(MalformedURLException e)
System.out.println("Invalid file or location");
return false;
catch (Exception e)
System.out.println("Other problem");
return false;
public void startPlaying()
player.start();
public void stopPlaying()
player.stop();
player.close();
public boolean prepareToRecord()
if (processor!=null)
processor.close();
Vector deviceList =
CaptureDeviceManager.getDeviceList(new AudioFormat
(AudioFormat.LINEAR));
CaptureDeviceInfo device = new
CaptureDeviceInfo();
if(deviceList.size()>0)
device = (CaptureDeviceInfo)
deviceList.lastElement();
System.out.println("Device found"+ device.toString());
else
System.out.println("Cannot find suitable device");
return false;
try
processor = Manager.createProcessor
(device.getLocator());
catch(IOException e)
System.out.println("IOException");
return false;
catch(NoProcessorException e)
System.out.println("No processor");
return false;
StateHandler sHandler = new StateHandler
(processor);
if(!sHandler.configured(10000))
System.out.println("Not configured");
return false;
processor.setContentDescriptor(new
FileTypeDescriptor(FileTypeDescriptor.WAVE));
//setContentDescriptor to type
if(!sHandler.realized(1000))
System.out.println("Not realized");
return false;
//Set output content type and realise processor
DataSource source =
processor.getDataOutput();
Control c = (Control)processor.getControl
("javax.media.control.BufferControl");
if (c != null)
int bufferLength = 500;
((BufferControl)c).setBufferLength
(bufferLength);
System.out.println("Buffer set at " +
bufferLength);
//create a file protocol MediaLocator with target file
String fileString = "file:///" + this.getPath();
MediaLocator target = new MediaLocator
(fileString);
//create a datasink to do writing to file and open sink
try
filewriter =
Manager.createDataSink(source,target);
System.out.println("Sink created");
filewriter.addDataSinkListener
(new sinkEventHandler());
filewriter.open();
System.out.println("filewriter open");
catch(Exception e)
System.out.println("error " + e);
return false;
try
filewriter.start();
System.out.println("filewriter started");
System.out.println("Start recording");
catch(IOException e)
System.out.println("filewriter start exception" + e);
return false;
return true;
public void startRecording()
processor.start();
public void stopRecording()
processor.stop();
processor.close();
filewriter.close();
public boolean prepareToSave()
try
if(processor != null)
processor.close();
Format formats[]=new Format[1];
formats[0] = new AudioFormat
(AudioFormat.ULAW,8000,8,1);
FileTypeDescriptor outputType =
(new FileTypeDescriptor(FileTypeDescriptor.BASIC_AUDIO));
String fileString = "file:///" +
this.getPath();
processor =
Manager.createRealizedProcessor(new ProcessorModel(new
MediaLocator(fileString),formats,outputType));
System.out.println("Processor created");
Control c = (Control)
processor.getControl("javax.media.control.BufferControl");
if (c != null)
int bufferLength = 500;
((BufferControl)c).setBufferLength
(bufferLength);
System.out.println("Buffer set at " +
bufferLength);
processor.addControllerListener(new
processorListener());
System.out.println("processor controller");
return true;
catch(IOException e)
{ System.out.println("IOException");
return false;
catch(NoProcessorException e)
{ System.out.println("No processor");
return false;
catch(CannotRealizeException e)
System.out.println
("CannotRealizeException");
return false;
catch(Exception e)
System.out.println("Error " + e);
return false;
public void setPlayerTime(Time time)
player.setMediaTime(time);
public void setPlayerStopTime(Time time)
player.setStopTime(time);
public void setProcessorTime(Time time)
processor.setMediaTime(time);
public void setProcessorStopTime(Time time)
processor.setStopTime(time);
public Time getPlayerTime()
Time time= player.getMediaTime();
return time;
public Time getProcessorTime()
Time time= processor.getMediaTime();
return time;
public boolean saveClip(String fileName)
if(!createSink(fileName))
return false;
clipSaved = false;
processor.start();
return true;
public void close()
if(player != null)
player.close();
if(processor != null)
processor.close();
if(filewriter != null)
filewriter.close();
public void deallocate()
if(player != null)
player.deallocate();
if(processor != null)
processor.deallocate();
private boolean createSink(String fileName)
//get output from processor
DataSource source = processor.getDataOutput
//create a file protocol MediaLocator with target file
MediaLocator target = new MediaLocator("file:///" + fileName);
//create a datasink to write to file and open sink
try
filewriter = Manager.createDataSink
(source,target);
filewriter.addDataSinkListener
(new sinkEventHandler());
filewriter.open();
System.out.println("Sink opened");
catch(NoDataSinkException e)
{ System.out.println("No DataSink");
return false;
catch(IOException e)
{ System.out.println("IO Exception");
return false;
catch(SecurityException e)
{ System.out.println("Security Exception");
return false;
try
{ filewriter.start();
System.out.println("Sink started");
catch(IOException e)
{ System.out.println("Filewriter start exception");
return false;
return true;
public class processorListener implements
ControllerListener
{ public void controllerUpdate(ControllerEvent
event)
{ if (event instanceof StopAtTimeEvent)
{ processor.stop();
processor.close();
System.out.println
("StopAtTimeEvent");
processor.deallocate();
System.out.println
("Processor closed");
clipSaved = true;
filewriter.close();
}