org.deepsymmetry.beatlink

Class MetadataFinder

java.lang.Object

org.deepsymmetry.beatlink.MetadataFinder

public class MetadataFinder
extends Object

Watches for new tracks to be loaded on players, and queries the appropriate player for the metadata information when that happens.

THIS CLASS IS NOT YET READY FOR USE.

Although it worked great for an entire weekend during which my network configuration remained constant, as soon as I reconfigured the network to remove the managed switch I was using to watch traffic between CDJs, the particular packets which had been working started to crash the process in the CDJs which responds to metadata queries, meaning they would need to be turned off and back on before any other CDJ could get Link Info from them.

We need to figure out how the byte patterns below need to change based on the network configuration, or based on values found in the device announcement or status packets, or in earlier response packets, in order to make this reliable and safe to use.

This goes along with the comment on the usbPacketTemplates array; perhaps if we can understand what is different about the packets that need to be sent to each player, we can understand how to accommodate the network configuration, and how to construct packets that always work.

Author:

James Elliott

Field Summary

Fields

Modifier and Type	Field and Description
static int	METADATA_PORT The port on which we contact players to ask them for metadata information.

Constructor Summary

Constructors

Constructor and Description
MetadataFinder()

Method Summary

Modifier and Type	Method and Description
static Map<Integer,TrackMetadata>	getLatestMetadata() Get all currently known metadata.
static TrackMetadata	getLatestMetadataFor(DeviceUpdate update) Look up the track metadata we have for a given player, identified by a status update received from that player.
static TrackMetadata	getLatestMetadataFor(int player) Look up the track metadata we have for a given player number.
static boolean	isRunning() Check whether we are currently running.
static TrackMetadata	requestMetadataFrom(CdjStatus status) Given a status update from a CDJ, find the metadata for the track that it has loaded, if any.
static TrackMetadata	requestMetadataFrom(int player, CdjStatus.TrackSourceSlot slot, int rekordboxId) Ask the specified player for metadata about the track in the specified slot with the specified rekordbox ID.
static void	start() Start finding track metadata for all active players.
static void	stop() Stop finding track metadata for all active players.

Methods inherited from class java.lang.Object

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

Field Detail

METADATA_PORT

public static final int METADATA_PORT

The port on which we contact players to ask them for metadata information.

See Also:

Constant Field Values

Constructor Detail

MetadataFinder

public MetadataFinder()

Method Detail

requestMetadataFrom

public static TrackMetadata requestMetadataFrom(CdjStatus status)

Given a status update from a CDJ, find the metadata for the track that it has loaded, if any.

Parameters:

status - the CDJ status update that will be used to determine the loaded track and ask the appropriate player for metadata about it

Returns:

the metadata that was obtained, if any

requestMetadataFrom

public static TrackMetadata requestMetadataFrom(int player,
                                                CdjStatus.TrackSourceSlot slot,
                                                int rekordboxId)

Ask the specified player for metadata about the track in the specified slot with the specified rekordbox ID.

Parameters:

player - the player number whose track is of interest

slot - the slot in which the track can be found

rekordboxId - the track of interest

Returns:

the metadata, if any

isRunning

public static boolean isRunning()

Check whether we are currently running.

Returns:

true if track metadata is being sought for all active players

getLatestMetadata

public static Map<Integer,TrackMetadata> getLatestMetadata()

Get all currently known metadata.

Returns:

the track information reported by all current players

getLatestMetadataFor

public static TrackMetadata getLatestMetadataFor(int player)

Look up the track metadata we have for a given player number.

Parameters:

player - the device number whose track metadata is desired

Returns:

information about the track loaded on that player, if available

getLatestMetadataFor

public static TrackMetadata getLatestMetadataFor(DeviceUpdate update)

Look up the track metadata we have for a given player, identified by a status update received from that player.

Parameters:

update - a status update from the player for which track metadata is desired

Returns:

information about the track loaded on that player, if available

start

public static void start()
                  throws Exception

Start finding track metadata for all active players. Starts the VirtualCdj if it is not already running, because we need it to send us device status updates to notice when new tracks are loaded.

Throws:

Exception - if there is a problem starting the required components

stop

public static void stop()

Stop finding track metadata for all active players.