Class DeviceUpdate

  • Direct Known Subclasses:
    Beat, CdjStatus, MixerStatus

    public abstract class DeviceUpdate
    extends Object
    Represents a device status update seen on a DJ Link network.
    Author:
    James Elliott
    • Constructor Summary

      Constructors 
      Constructor Description
      DeviceUpdate​(DatagramPacket packet, String name, int length)
      Constructor sets all the immutable interpreted fields based on the packet content.
    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      InetAddress getAddress()
      Get the address of the device from which this update was seen.
      abstract int getBeatWithinBar()
      Get the position within a measure of music at which the most recent beat fell (a value from 1 to 4, where 1 represents the down beat).
      abstract int getBpm()
      Get the playback BPM at the time of the update.
      abstract Integer getDeviceMasterIsBeingYieldedTo()
      If this packet indicates the device in the process of yielding the tempo master role to another player, this will hold the device number of that player, otherwise it will be null.
      String getDeviceName()
      Get the name reported by the device sending the update.
      int getDeviceNumber()
      Get the player/device number reporting the update.
      abstract double getEffectiveTempo()
      Get the effective tempo reflected by this update, which reflects both its track BPM and pitch as needed.
      byte[] getPacketBytes()
      Get the raw data bytes of the device update packet.
      abstract int getPitch()
      Get the device pitch at the time of the update.
      long getTimestamp()
      Get the timestamp recording when the device update was received.
      abstract boolean isBeatWithinBarMeaningful()
      Returns true if this update is coming from a device where getBeatWithinBar() can reasonably be expected to have musical significance, because it respects the way a track was configured within rekordbox.
      boolean isPreNexusCdj()
      Check whether this packet seems to have come from a CDJ older than the original Nexus series (which means, for example, that beat numbers will not be available, so the TimeFinder can't work with it.
      abstract boolean isSynced()
      Is this device reporting itself synced to the current tempo master?
      abstract boolean isTempoMaster()
      Is this device reporting itself to be the current tempo master?
      String toString()  
    • Constructor Detail

      • DeviceUpdate

        public DeviceUpdate​(DatagramPacket packet,
                            String name,
                            int length)
        Constructor sets all the immutable interpreted fields based on the packet content.
        Parameters:
        packet - the device update packet that was received
        name - the type of packet that is being processed, in case a problem needs to be reported
        length - the expected length of the packet
    • Method Detail

      • getAddress

        public InetAddress getAddress()
        Get the address of the device from which this update was seen.
        Returns:
        the network address from which the update was sent
      • getTimestamp

        public long getTimestamp()
        Get the timestamp recording when the device update was received.
        Returns:
        the nanosecond timestamp at which we received this update
      • getDeviceName

        public String getDeviceName()
        Get the name reported by the device sending the update.
        Returns:
        the device name
      • isPreNexusCdj

        public boolean isPreNexusCdj()
        Check whether this packet seems to have come from a CDJ older than the original Nexus series (which means, for example, that beat numbers will not be available, so the TimeFinder can't work with it.
        Returns:
        true if the device name starts with "CDJ" and ends with "0".
      • getDeviceNumber

        public int getDeviceNumber()
        Get the player/device number reporting the update.
        Returns:
        the player number found in the update packet
      • getPacketBytes

        public byte[] getPacketBytes()
        Get the raw data bytes of the device update packet.
        Returns:
        the data sent by the device to update its status
      • getPitch

        public abstract int getPitch()
        Get the device pitch at the time of the update. This is an integer ranging from 0 to 2097152, which corresponds to a range between completely stopping playback to playing at twice normal tempo. The equivalent percentage value can be obtained by passing the pitch to Util.pitchToPercentage(long), and the corresponding fractional scaling value by passing it to Util.pitchToMultiplier(long). Mixers always report a pitch of +0%, so tempo changes are purely reflected in the BPM value.
        Returns:
        the raw effective device pitch at the time of the update
      • getBpm

        public abstract int getBpm()
        Get the playback BPM at the time of the update. This is an integer representing the BPM times 100, so a track running at 120.5 BPM would be represented by the value 12050. Mixers always report a pitch of +0%, so tempo changes are purely reflected in the BPM value.

        When the CDJ has just started up and no track has been loaded, it will report a BPM of 65535.

        Returns:
        the track BPM to two decimal places multiplied by 100
      • isTempoMaster

        public abstract boolean isTempoMaster()
        Is this device reporting itself to be the current tempo master?
        Returns:
        true if the device that sent this update is the master
        Throws:
        IllegalStateException - if called with a Beat and the VirtualCdj is not running, since that is needed to find the latest status update from the device which sent the beat packet.
      • isSynced

        public abstract boolean isSynced()
        Is this device reporting itself synced to the current tempo master?
        Returns:
        true if the device that sent this update is synced
        Throws:
        IllegalStateException - if called with a Beat and the VirtualCdj is not running, since that is needed to find the latest status update from the device which sent the beat packet.
      • getDeviceMasterIsBeingYieldedTo

        public abstract Integer getDeviceMasterIsBeingYieldedTo()
        If this packet indicates the device in the process of yielding the tempo master role to another player, this will hold the device number of that player, otherwise it will be null.
        Returns:
        the device number, if any, this update is yielding the tempo master role to
      • getEffectiveTempo

        public abstract double getEffectiveTempo()
        Get the effective tempo reflected by this update, which reflects both its track BPM and pitch as needed.
        Returns:
        the beats per minute this device is reporting
      • getBeatWithinBar

        public abstract int getBeatWithinBar()
        Get the position within a measure of music at which the most recent beat fell (a value from 1 to 4, where 1 represents the down beat). This value will be accurate for players when the track was properly configured within rekordbox (and if the music follows a standard House 4/4 time signature). The mixer makes no effort to synchronize down beats with players, however, so this value is meaningless when coming from the mixer. The usefulness of this value can be checked with isBeatWithinBarMeaningful().
        Returns:
        the beat number within the current measure of music
      • isBeatWithinBarMeaningful

        public abstract boolean isBeatWithinBarMeaningful()
        Returns true if this update is coming from a device where getBeatWithinBar() can reasonably be expected to have musical significance, because it respects the way a track was configured within rekordbox.
        Returns:
        true for status packets from players, false for status packets from mixers