Package org.hibernate.search.engine.search.projection.spi

Class SingleValuedProjectionAccumulator<F,V>

java.lang.Object

org.hibernate.search.engine.search.projection.spi.SingleValuedProjectionAccumulator<F,V>

Type Parameters:

F - The type of (unconverted) field values.

V - The type of field values after the projection converter was applied.

All Implemented Interfaces:

ProjectionAccumulator<F,V,F,V>

public final class SingleValuedProjectionAccumulator<F,V>
extends Object
implements ProjectionAccumulator<F,V,F,V>

A ProjectionAccumulator that can accumulate up to one value, and will throw an exception beyond that.

Nested Class Summary

Nested classes/interfaces inherited from interface org.hibernate.search.engine.search.projection.spi.ProjectionAccumulator

ProjectionAccumulator.Provider<V,R>

Method Summary

Modifier and Type	Method	Description
F	accumulate(F accumulated, F value)	Folds a new value in the given accumulated container.
F	createInitial()	Creates the initial accumulated container.
V	finish(F accumulated, ProjectionConverter<? super F,? extends V> converter, FromDocumentValueConvertContext context)	Finishes the collecting, converting the accumulated container into the final result.
static <V> ProjectionAccumulator.Provider<V,V>	provider()
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

provider

public static <V> ProjectionAccumulator.Provider<V,V> provider()

toString

public String toString()

Overrides:

toString in class Object

createInitial

public F createInitial()

Description copied from interface: ProjectionAccumulator

Creates the initial accumulated container.

This operation should be non-blocking.

Specified by:

createInitial in interface ProjectionAccumulator<F,V,F,V>

Returns:

The initial accumulated container, to pass to the first call to ProjectionAccumulator.accumulate(Object, Object).

accumulate

public F accumulate(F accumulated,
                    F value)

Description copied from interface: ProjectionAccumulator

Folds a new value in the given accumulated container.

This operation should be non-blocking.

Specified by:

accumulate in interface ProjectionAccumulator<F,V,F,V>

Parameters:

accumulated - The accumulated value so far. For the first call, this is a value returned by ProjectionAccumulator.createInitial(). For the next calls, this is the value returned by the previous call to ProjectionAccumulator.accumulate(Object, Object).

value - The value to accumulate.

Returns:

The new accumulated value.

finish

public V finish(F accumulated,
                ProjectionConverter<? super F,? extends V> converter,
                FromDocumentValueConvertContext context)

Description copied from interface: ProjectionAccumulator

Finishes the collecting, converting the accumulated container into the final result.

This operation may be blocking.

Specified by:

finish in interface ProjectionAccumulator<F,V,F,V>

Parameters:

accumulated - The temporary storage created by ProjectionAccumulator.createInitial() and populated by successive calls to ProjectionAccumulator.accumulate(Object, Object).

converter - The projection converter (from F to V).

context - The context to be passed to the projection converter.

Returns:

The final result of the collecting.