Package nz.org.riskscape.engine.projection

Interface Projector

All Superinterfaces:

AutoCloseable, Function<Tuple,Tuple>, Realized

public interface Projector
extends Function<Tuple,Tuple>, Realized

Realized Projection of one Struct to another. Exists so that a Projection's projection function can be associated with other metadata, such as the source and target Struct and a possible mapping of attributes from one to the other.

Method Summary

Modifier and Type	Method	Description
default Map<List<Struct.StructMember>,List<Struct.StructMember>>	getDirectMapping()
default Map<String,String>	getDirectMappingStrings()
Struct	getProducedType()	The exact Struct object that will be assigned to Tuples that emerge from this Projector
default Struct	getProjectedType()	Deprecated. use getProducedType
Struct	getSourceType()	The exact Struct object that is expected to be seen by the Function.apply(java.lang.Object)
default Optional<Function<SpatialMetadata,SpatialMetadata>>	getSpatialMetadataMapper()	An optional function used for transforming spatial metadata from source to target.
static Map<List<Struct.StructMember>,List<Struct.StructMember>>	identityMapping(Struct struct)
static String	join(List<Struct.StructMember> members)

Methods inherited from interface java.util.function.Function

andThen, apply, compose

Methods inherited from interface nz.org.riskscape.engine.pipeline.Realized

close

Method Details

join

static String join(List<Struct.StructMember> members)

identityMapping

static Map<List<Struct.StructMember>,List<Struct.StructMember>> identityMapping(Struct struct)

getProducedType

Struct getProducedType()

The exact Struct object that will be assigned to Tuples that emerge from this Projector

Specified by:

getProducedType in interface Realized

getProjectedType

@Deprecated
default Struct getProjectedType()

Deprecated.

use getProducedType

getSourceType

Struct getSourceType()

The exact Struct object that is expected to be seen by the Function.apply(java.lang.Object)

getDirectMapping

default Map<List<Struct.StructMember>,List<Struct.StructMember>> getDirectMapping()

Returns:

a map that can be used to trace attributes from the target type (the key set) back to their source type (value set). Optional, as this is here to allow various optimisations to be applied to queries. Not implementing this method will prevent various optimisations for being possible.

getSpatialMetadataMapper

default Optional<Function<SpatialMetadata,SpatialMetadata>> getSpatialMetadataMapper()

An optional function used for transforming spatial metadata from source to target. If left out, spatial metadata is lost during projection. A default, fairly sane implementation exists that copies the CRS and picks the single geometry member that was found at the top level of the projectors projected type.

getDirectMappingStrings

default Map<String,String> getDirectMappingStrings()

Returns:

a human-readable version of getDirectMapping(), useful for debug statements, test assertions etc