net.openhft.chronicle.wire.domestic.reduction

Interface Reduction<T>

All Superinterfaces:

ExcerptListener

All Known Implementing Classes:

Reductions.Counting

public interface Reduction<T>
extends ExcerptListener

This is the Reduction interface which extends ExcerptListener. It provides a means to consume excerpts from a given wire and apply reductions on them. The implementations of this interface should be thread-safe, especially if they are referenced as an ExcerptListener.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Reduction.DoubleReductionBuilder DoubleReductionBuilder is an interface that defines the contract for creating Reductions specialized for handling double data types.
static interface	Reduction.LongReductionBuilder LongReductionBuilder is an interface that defines the contract for creating Reductions specialized for handling long data types.
static interface	Reduction.ReductionBuilder<E> ReductionBuilder is an interface that defines the contract for creating new Reductions using a specific collector.

Method Summary

Modifier and Type	Method and Description
default long	accept(@NotNull MarshallableIn tailer) Accepts the input of the provided tailer and reduces (folds) the contents of it into this Reduction returning the last seen index or -1 if no index was seen.
static <E> Reduction.ReductionBuilder<E>	of(@NotNull DocumentExtractor<E> extractor) Creates and returns a new ReductionBuilder that will use the provided extractor to extract elements of type E.
static Reduction.DoubleReductionBuilder	ofDouble(@NotNull ToDoubleDocumentExtractor extractor) Creates and returns a new DoubleReductionBuilder that will use the provided extractor to extract elements of type double.
static Reduction.LongReductionBuilder	ofLong(@NotNull ToLongDocumentExtractor extractor) Creates and returns a new LongReductionBuilder that will use the provided extractor to extract elements of type long.
void	onExcerpt(@NotNull Wire wire, long index) Consumes an excerpt from the provided wire at the index at the provided index.
T	reduction() Returns a view of the underlying reduction.

Methods inherited from interface net.openhft.chronicle.wire.ExcerptListener

andThen

Method Detail

onExcerpt

void onExcerpt(@NotNull
               @NotNull Wire wire,
               long index)
        throws net.openhft.chronicle.core.io.InvalidMarshallableException

Consumes an excerpt from the provided wire at the index at the provided index.

If this method throws an Exception, it is relayed to the call site. Therefore, care should be taken to minimise the probability of throwing Exceptions.

If this method is referenced as an ExcerptListener then the Reduction must be thread-safe.

Specified by:

onExcerpt in interface ExcerptListener

Parameters:

wire - representing access to the excerpt that was stored (non-null).

index - in the queue where the except was placed (non-negative)

Throws:

net.openhft.chronicle.core.io.InvalidMarshallableException

reduction

@NotNull
T reduction()

Returns a view of the underlying reduction.

Returns:

Reduction view.

accept

default long accept(@NotNull
                    @NotNull MarshallableIn tailer)
             throws net.openhft.chronicle.core.io.InvalidMarshallableException

Accepts the input of the provided tailer and reduces (folds) the contents of it into this Reduction returning the last seen index or -1 if no index was seen.

This method can be used to initialise a Reduction before appending new values.

It is the responsibility of the caller to make sure no simultaneous appenders are using this Reduction during the entire fold operation.

Parameters:

tailer - to reduce (fold) from

Returns:

the last index seen or -1 if no index was seen

Throws:

NullPointerException - if the provided tailer is null

net.openhft.chronicle.core.io.InvalidMarshallableException

of

static <E> Reduction.ReductionBuilder<E> of(@NotNull
                                            @NotNull DocumentExtractor<E> extractor)

Creates and returns a new ReductionBuilder that will use the provided extractor to extract elements of type E.

This method initializes a generic reduction builder suitable for custom element types.

Type Parameters:

E - the element type

Parameters:

extractor - the document extractor used to extract elements, must not be null

Returns:

a new ReductionBuilder instance

See Also:

Reduction.LongReductionBuilder, Reduction.DoubleReductionBuilder

ofLong

static Reduction.LongReductionBuilder ofLong(@NotNull
                                             @NotNull ToLongDocumentExtractor extractor)

Creates and returns a new LongReductionBuilder that will use the provided extractor to extract elements of type long.

This method initializes a reduction builder specifically for handling long values.

Parameters:

extractor - the document extractor for long values, must not be null

Returns:

a new LongReductionBuilder instance

See Also:

ofDouble(ToDoubleDocumentExtractor)

ofDouble

static Reduction.DoubleReductionBuilder ofDouble(@NotNull
                                                 @NotNull ToDoubleDocumentExtractor extractor)

Creates and returns a new DoubleReductionBuilder that will use the provided extractor to extract elements of type double.

This method initializes a reduction builder specifically for handling double values.

Parameters:

extractor - the document extractor for double values, must not be null

Returns:

a new DoubleReductionBuilder instance

See Also:

of(DocumentExtractor), ofLong(ToLongDocumentExtractor)