Class BaseChannel<ValueType, UpdateType, CheckpointType>Abstract

constructor

• new BaseChannel<ValueType, UpdateType, CheckpointType>(): BaseChannel<ValueType, UpdateType, CheckpointType>

• Type Parameters

  • ValueType = unknown
  • UpdateType = unknown
  • CheckpointType = unknown

  Returns BaseChannel<ValueType, UpdateType, CheckpointType>

UpdateType

ValueType

Abstract lc_graph_name

Abstract checkpoint

• checkpoint(): undefined | CheckpointType

• Return a string representation of the channel's current state.

  Returns undefined | CheckpointType

  Throws

  if the channel is empty (never updated yet), or doesn't support checkpoints.

consume

• consume(): boolean

• Mark the current value of the channel as consumed. By default, no-op. This is called by Pregel before the start of the next step, for all channels that triggered a node. If the channel was updated, return true.

  Returns boolean

Abstract fromCheckpoint

• fromCheckpoint(checkpoint?): this

• Return a new identical channel, optionally initialized from a checkpoint. Can be thought of as a "restoration" from a checkpoint which is a "snapshot" of the channel's state.

  Parameters

  • Optional checkpoint: CheckpointType

  Returns this

Abstract get

• get(): ValueType

• Return the current value of the channel.

  Returns ValueType

  Throws

  if the channel is empty (never updated yet).

Abstract update

• update(values): boolean

• Update the channel's value with the given sequence of updates. The order of the updates in the sequence is arbitrary. This method is called by Pregel for all channels at the end of each step. If there are no updates, it is called with an empty sequence.

  Raises InvalidUpdateError if the sequence of updates is invalid. Returns True if the channel was updated, False otherwise.

  Parameters

  • values: UpdateType[]

  Returns boolean

  Throws

  if the sequence of updates is invalid.