io.r2dbc.spi

Interface Result

public interface Result

Represents the results of a query against a database. Results can be consumed only once by either consuming getRowsUpdated(), map(BiFunction), or map(Function).

A Result object maintains a consumption state that may be backed by a cursor pointing to its current row of data or out parameters. A Result allows read-only and forward-only consumption of statement results. Thus, you can consume either getRowsUpdated(), Rows, or Rows or out parameters through it only once and only from the first to the last row/parameter set.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Result.Message Message segment reported as result of the statement processing.
static interface	Result.OutSegment Out parameters segment consisting of readable data.
static interface	Result.RowSegment Row segment consisting of row data.
static interface	Result.Segment Marker interface for a result segment.
static interface	Result.UpdateCount Update count segment consisting providing a affected rows count.

Method Summary

Modifier and Type	Method and Description
Result	filter(Predicate<Result.Segment> filter) Returns a filtered variant of the Result to selectively consume result segments matching filter predicate.
<T> Publisher<T>	flatMap(Function<Result.Segment,? extends Publisher<? extends T>> mappingFunction) Returns a mapping of the result segments that are the results of a query against a database.
Publisher<Long>	getRowsUpdated() Returns the number of rows updated by a query against a database.
<T> Publisher<T>	map(BiFunction<Row,RowMetadata,? extends T> mappingFunction) Returns a mapping of the rows that are the results of a query against a database.
default <T> Publisher<T>	map(Function<? super Readable,? extends T> mappingFunction) Returns a mapping of the rows/out parameters that are the results of a query against a database.

Method Detail

getRowsUpdated

Publisher<Long> getRowsUpdated()

Returns the number of rows updated by a query against a database. May be empty if the query did not update any rows.

Consuming the update count may emit an error signal if the results contain one or more error message segments.

Returns:

the number of rows updated by a query against a database

Throws:

IllegalStateException - if the result was consumed

map

<T> Publisher<T> map(BiFunction<Row,RowMetadata,? extends T> mappingFunction)

Returns a mapping of the rows that are the results of a query against a database. May be empty if the query did not return any rows. A Row can be only considered valid within a mapping function callback.

Consuming data rows may emit an error signal if the results contain one or more error message segments.

Type Parameters:

T - the type of the mapped value

Parameters:

mappingFunction - the BiFunction that maps a Row and RowMetadata to a value

Returns:

a mapping of the rows that are the results of a query against a database

Throws:

IllegalArgumentException - if mappingFunction is null

IllegalStateException - if the result was consumed

map

default <T> Publisher<T> map(Function<? super Readable,? extends T> mappingFunction)

Returns a mapping of the rows/out parameters that are the results of a query against a database. May be empty if the query did not return any results. A Readable can be only considered valid within a mapping function callback.

Type Parameters:

T - the type of the mapped value

Parameters:

mappingFunction - the Function that maps a Readable to a value

Returns:

a mapping of the rows that are the results of a query against a database

Throws:

IllegalArgumentException - if mappingFunction is null

IllegalStateException - if the result was consumed

Since:

0.9

See Also:

Row, OutParameters

filter

Result filter(Predicate<Result.Segment> filter)

Returns a filtered variant of the Result to selectively consume result segments matching filter predicate.

The returned Result is a potentially reduced view of the underlying Result to filter out unwanted result segments. For example, filtering all Result.Message segments from the result lets the result complete without an error.

Parameters:

filter - the non-interfering and stateless Predicate to apply to each element to determine if it should be included

Returns:

a filtered Result

Throws:

IllegalArgumentException - if filter is null

IllegalStateException - if the result was consumed

Since:

0.9

flatMap

<T> Publisher<T> flatMap(Function<Result.Segment,? extends Publisher<? extends T>> mappingFunction)

Returns a mapping of the result segments that are the results of a query against a database. May be empty if the query did not return any segments. A Result.Segment can be only considered valid within a mapping function callback.

Consuming result segments does not emit error signals from message segments representing an error. Translation of error segments is subject to the mappingFunction.

Signals from mapped publishers are replayed sequentially preserving ordering by concatenating publishers.

Type Parameters:

T - the type of the mapped value

Parameters:

mappingFunction - the Function that maps a Result.Segment a to a Publisher

Returns:

a mapping of the segments that are the results of a query against a database

Throws:

IllegalArgumentException - if mappingFunction is null

IllegalStateException - if the result was consumed

Since:

0.9