dsl/it.unibo.collektive.aggregate/AggregateContext

AggregateContext

class AggregateContext(localId: ID, messages: Collection<InboundMessage>, previousState: Set<State<*>>)

Context for managing aggregate computation. It represents the localId of the device, the messages received from the neighbours, and the previousState of the device.

Constructors

AggregateContext

constructor(localId: ID, messages: Collection<InboundMessage>, previousState: Set<State<*>>)

Functions

alignedOn

fun <R> alignedOn(pivot: Any?, body: () -> R): R

Alignment function that pushes in the stack the pivot, executes the body and pop the last element of the stack after it is called. Returns the body's return element.

exchange

fun <X> exchange(initial: X, body: (Field<X>) -> Field<X>): Field<X>

This function computes the local value of e_i, substituting variable n with the nvalue w of messages received from neighbours, using the local value of e_i (initial) as a default. The exchange returns the neighbouring or local value v_r from the evaluation of e_r applied to the body. e_s evaluates to a nvalue w_s consisting of local values to be sent to neighbour devices δ′, which will use their corresponding w_s(δ') as soon as they wake up and perform their next execution round.

messagesToSend

fun messagesToSend(): OutboundMessage

Messages to send to the other nodes.

neighbouring

fun <Return> AggregateContext.neighbouring(type: Return): Field<Return>

Observes the value of an expression type across neighbours.

newState

fun newState(): Set<State<*>>

Return the current state of the device as a new state.

repeating

fun <X, Y> repeating(initial: X, repeat: (X) -> Y): Y

Iteratively updates the value of the input expression repeat at each device using the last computed value or the initial.

fun <Initial> AggregateContext.share(initial: Initial, transform: (Field<Initial>) -> Initial): Initial

share captures the space-time nature of field computation through observation of neighbours' values, starting from an initial value, it reduces to a single local value given a transform function and updating and sharing to neighbours of a local variable.

sharing

fun <Initial, Return> AggregateContext.sharing(initial: Initial, transform: SharingContext<Initial, Return>.(Field<Initial>) -> SharingResult<Initial, Return>): Return

sharing captures the space-time nature of field computation through observation of neighbours' values, starting from an initial value, it reduces to a single local value given a transform function and updating and sharing to neighbours of a local variable.