net.sf.dvbcentral.lib
Class Frontend

java.lang.Object
  net.sf.dvbcentral.lib.Frontend

All Implemented Interfaces:

Closeable, Channel, ReadableByteChannel

public final class Frontend
extends Object
implements ReadableByteChannel

Abstraction over a DVB frontend. Instances can be created using find(int) method and allows one to tune to any frequency (see Tune), subscribe to certain PIDs using openPID(int) and read the transmitted data through ReadableByteChannel.read(java.nio.ByteBuffer) method.

Nested Class Summary

static class	Frontend.PID Represents one pid.
static class	Frontend.Stats A structure representing a snapshot of frontends' radio performance statistics.

Method Summary

void	close()
static Frontend	createVirtual(ReadableByteChannel channel, Collection<? super Frontend.PID> pids, Collection<? super Tune> tunes) Creates a fake, virtual frontend that delegates all of its operations on provided interfaces.
static Frontend	find(int device) Basic factory method for creating frontend for devices registered in the system.
Frontend.Stats	getStats() Retrieves the radio performance statistics from the frontend.
boolean	isOpen()
Frontend.PID	openPID(int pid) Opens new PID for reading.
int	read(ByteBuffer byteBuffer)
void	tune(Tune tune) Tunes the frontend to new frequency and other aspects provided by given tune.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

find

public static Frontend find(int device)
                     throws IOException

Basic factory method for creating frontend for devices registered in the system.

Parameters:

device - number of the adapter to create frontend for

Throws:

IOException

createVirtual

public static Frontend createVirtual(ReadableByteChannel channel,
                                     Collection<? super Frontend.PID> pids,
                                     Collection<? super Tune> tunes)

Creates a fake, virtual frontend that delegates all of its operations on provided interfaces. All the methods that read delegate to the provided ReadableByteChannel implementation. The other arguments are not necessary, but if one of them is provided, their methods are going to be called as follows: frontend.openPID(...) results in a call to pids.add(theNewlyCreatedPid) and closing the pid results in pids.remove(theClosedPid). Calls to tune are going to result in a call to tunes.add(theTune).

Parameters:

channel - the channel to read the data from

pids - the collection to add and remove opened pids from, can be null

tunes - the collection to add the tunes called on this frontend to, can be null

Returns:

an new instance of a virtual frontend

Since:

1.4

tune

public void tune(Tune tune)
          throws IOException

Tunes the frontend to new frequency and other aspects provided by given tune.

Parameters:

tune - the tune to tune to

Throws:

IOException - if tuning failed

openPID

public Frontend.PID openPID(int pid)
                     throws IOException

Opens new PID for reading. This is method returns a handle, which one has to hold to receive the packets for the given pid.

Parameters:

pid - integer number describing the PID

Returns:

handle to control the receiver

Throws:

IOException - if opening pid fails

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface Channel

Throws:

IOException

isOpen

public boolean isOpen()

Specified by:

isOpen in interface Channel

read

public int read(ByteBuffer byteBuffer)
         throws IOException

Specified by:

read in interface ReadableByteChannel

Throws:

IOException

getStats

public Frontend.Stats getStats()

Retrieves the radio performance statistics from the frontend.

Returns:

a structure containing a snapshot of frontend statistics.