de.grogra.xl.lang
Interface AggregateState

All Known Subinterfaces:

BooleanAggregateState, ByteAggregateState, CharAggregateState, DoubleAggregateState, FloatAggregateState, IntAggregateState, LongAggregateState, ObjectAggregateState<T>, ShortAggregateState

All Known Implementing Classes:

AggregateStateImpl

public interface AggregateState

An instance of AggregateState is used in aggregate method invocations as specified by the XL programming language. Aggregate methods use such an instance to collect the information about a sequence of values which they need to compute an aggregate value, and to tell the invoker if the computation is already finished even if there are values left.

This interface is abstract in the sense that only its direct subinterfaces BooleanAggregateState, ..., ObjectAggregateState are used by the specification of the XL programming language and only those should be implemented.

Author:

Ole Kniemeyer

Method Summary

boolean

isFinished() Returns true to indicate the invoker of the aggregate method that the computation of the aggregate value has been completed by the aggregate method, even if there are values left for aggregation.

Method Detail

isFinished

boolean isFinished()

Returns true to indicate the invoker of the aggregate method that the computation of the aggregate value has been completed by the aggregate method, even if there are values left for aggregation. E.g., this is the case for a short circuit implementation of the boolean or where the result is known when the first true-value is encountered. The invoker must not invoke the aggregate method again.

Returns:

true iff the final aggregated value is already known