org.heigit.bigspatialdata.oshdb.api.mapreducer.backend

Class MapReducerIgniteLocalPeek<X>

java.lang.Object

org.heigit.bigspatialdata.oshdb.api.mapreducer.MapReducer<X>

org.heigit.bigspatialdata.oshdb.api.mapreducer.backend.MapReducerIgniteLocalPeek<X>

All Implemented Interfaces:

Serializable, Mappable<X>

public class MapReducerIgniteLocalPeek<X>
extends MapReducer<X>

Main class of oshdb's "functional programming" API.

It accepts a list of filters, transformation `map` functions a produces a result when calling the `reduce` method (or one of its shorthand versions like `sum`, `count`, etc.).

You can set a list of filters that are applied on the raw OSM data, for example you can filter:

• geometrically by an area of interest (bbox or polygon)
• by osm tags (key only or key/value)
• by OSM type
• custom filter callback

Depending on the used data "view", the MapReducer produces either "snapshots" or evaluated all modifications ("contributions") of the matching raw OSM data.

These data can then be transformed arbitrarily by user defined `map` functions (which take one of these entity snapshots or modifications as input an produce an arbitrary output) or `flatMap` functions (which can return an arbitrary number of results per entity snapshot/contribution). It is possible to chain together any number of transformation functions.

Finally, one can either use one of the pre-defined result-generating functions (e.g. `sum`, `count`, `average`, `uniq`), or specify a custom `reduce` procedure.

If one wants to get results that are aggregated by timestamp (or some other index), one can use the `aggregateByTimestamp` or `aggregateBy` functionality that automatically handles the grouping of the output data.

For more complex analyses, it is also possible to enable the grouping of the input data by the respective OSM ID. This can be used to view at the whole history of entities at once.

The "LocalPeek" implementation is the a very versatile implementation of the oshdb mapreducer on Ignite: It offers high performance, scalability and cancelable queries. It should be used in most situations when running oshdb- analyses on ignite.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.heigit.bigspatialdata.oshdb.api.mapreducer.MapReducer

bboxFilter, keytables, oshdb, timeout, tstamps, typeFilter

Constructor Summary

Constructors

Constructor and Description
MapReducerIgniteLocalPeek(OSHDBDatabase oshdb, Class<? extends OSHDBMapReducible> forClass)

Method Summary

Modifier and Type	Method and Description
protected MapReducer<X>	copy()
protected <R,S> S	flatMapReduceCellsOSMContributionGroupedById(SerializableFunction<List<OSMContribution>,Iterable<R>> mapper, SerializableSupplier<S> identitySupplier, SerializableBiFunction<S,R,S> accumulator, SerializableBinaryOperator<S> combiner) Generic "flat" version of the map-reduce used by the `OSMContributionView`, with by-osm-id grouped input to the `mapper` function.
protected <R,S> S	flatMapReduceCellsOSMEntitySnapshotGroupedById(SerializableFunction<List<OSMEntitySnapshot>,Iterable<R>> mapper, SerializableSupplier<S> identitySupplier, SerializableBiFunction<S,R,S> accumulator, SerializableBinaryOperator<S> combiner) Generic "flat" version of the map-reduce used by the `OSMEntitySnapshotView`, with by-osm-id grouped input to the `mapper` function.
boolean	isCancelable() Returns if the current backend can be canceled (e.g.
protected <R,S> S	mapReduceCellsOSMContribution(SerializableFunction<OSMContribution,R> mapper, SerializableSupplier<S> identitySupplier, SerializableBiFunction<S,R,S> accumulator, SerializableBinaryOperator<S> combiner) Generic map-reduce used by the `OSMContributionView`.
protected <R,S> S	mapReduceCellsOSMEntitySnapshot(SerializableFunction<OSMEntitySnapshot,R> mapper, SerializableSupplier<S> identitySupplier, SerializableBiFunction<S,R,S> accumulator, SerializableBinaryOperator<S> combiner) Generic map-reduce used by the `OSMEntitySnapshotView`.
default M	osmType(OSMType type1, OSMType... otherTypes) Limits the analysis to the given osm entity types.
default M	osmTypes(EnumSet<OSMType> typeFilter) Deprecated. replaced by osmType(OSMType, OSMType...)
default M	osmTypes(OSMType type1, OSMType... otherTypes) Deprecated. replaced by osmType(OSMType, OSMType...)
default M	where(Collection<OSMTag> keyValuePairs) Deprecated. replaced by osmTag(Collection)
default M	where(OSMTag tag) Deprecated. replaced by osmTag(OSMTagInterface)
default M	where(OSMTagKey key) Deprecated. replaced by osmTag(OSMTagInterface)
default M	where(SerializablePredicate<OSMEntity> f) Deprecated. replaced by osmEntityFilter(org.heigit.bigspatialdata.oshdb.api.generic.function.SerializablePredicate<org.heigit.bigspatialdata.oshdb.osm.OSMEntity>)
default M	where(String key) Deprecated. replaced by osmTag(String)
default M	where(String key, Collection<String> values) Deprecated. replaced by osmTag(String, Collection)
default M	where(String key, Pattern valuePattern) Deprecated. replaced by osmTag(String, Pattern)
default M	where(String key, String value) Deprecated. replaced by osmTag(String, String)

Methods inherited from class org.heigit.bigspatialdata.oshdb.api.mapreducer.MapReducer

aggregateBy, aggregateBy, aggregateByGeometry, aggregateByTimestamp, aggregateByTimestamp, areaOfInterest, areaOfInterest, average, average, collect, count, countUniq, estimatedMedian, estimatedMedian, estimatedQuantile, estimatedQuantile, estimatedQuantiles, estimatedQuantiles, estimatedQuantiles, estimatedQuantiles, filter, flatMap, flatMapStreamCellsOSMContributionGroupedById, flatMapStreamCellsOSMEntitySnapshotGroupedById, forEach, getCellIdRanges, getFilter, getPolyFilter, getPreFilter, getTagInterpreter, getTagTranslator, groupByEntity, keytables, map, mapStreamCellsOSMContribution, mapStreamCellsOSMEntitySnapshot, osmEntityFilter, osmTag, osmTag, osmTag, osmTag, osmTag, osmTag, osmType, reduce, reduce, stream, sum, sum, tagInterpreter, timestamps, timestamps, timestamps, timestamps, timestamps, uniq, uniq, weightedAverage

Methods inherited from class java.lang.Object

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

Constructor Detail

MapReducerIgniteLocalPeek

public MapReducerIgniteLocalPeek(OSHDBDatabase oshdb,
                                 Class<? extends OSHDBMapReducible> forClass)

Method Detail

copy

@NotNull
protected MapReducer<X> copy()

Specified by:

copy in class MapReducer<X>

isCancelable

public boolean isCancelable()

Description copied from class: MapReducer

Returns if the current backend can be canceled (e.g. in a query timeout).

Overrides:

isCancelable in class MapReducer<X>

mapReduceCellsOSMContribution

protected <R,S> S mapReduceCellsOSMContribution(SerializableFunction<OSMContribution,R> mapper,
                                                SerializableSupplier<S> identitySupplier,
                                                SerializableBiFunction<S,R,S> accumulator,
                                                SerializableBinaryOperator<S> combiner)
                                         throws Exception

Description copied from class: MapReducer

Generic map-reduce used by the `OSMContributionView`.

The combination of the used types and identity/reducer functions must make "mathematical" sense:

• the accumulator and combiner functions need to be associative,
• values generated by the identitySupplier factory must be an identity for the combiner function: `combiner(identitySupplier(),x)` must be equal to `x`,
• the combiner function must be compatible with the accumulator function: `combiner(u, accumulator(identitySupplier(), t)) == accumulator.apply(u, t)`

Functionally, this interface is similar to Java8 Stream's reduce(identity,accumulator,combiner) interface.

Overrides:

mapReduceCellsOSMContribution in class MapReducer<X>

Type Parameters:

R - the data type returned by the `mapper` function

S - the data type used to contain the "reduced" (intermediate and final) results

Parameters:

mapper - a function that's called for each `OSMContribution`

identitySupplier - a factory function that returns a new starting value to reduce results into (e.g. when summing values, one needs to start at zero)

accumulator - a function that takes a result from the `mapper` function (type <R>) and an accumulation value (type <S>, e.g. the result of `identitySupplier()`) and returns the "sum" of the two; contrary to `combiner`, this function is allowed to alter (mutate) the state of the accumulation value (e.g. directly adding new values to an existing Set object)

combiner - a function that calculates the "sum" of two <S> values; this function must be pure (have no side effects), and is not allowed to alter the state of the two input objects it gets!

Returns:

the result of the map-reduce operation, the final result of the last call to the `combiner` function, after all `mapper` results have been aggregated (in the `accumulator` and `combiner` steps)

Throws:

Exception

flatMapReduceCellsOSMContributionGroupedById

protected <R,S> S flatMapReduceCellsOSMContributionGroupedById(SerializableFunction<List<OSMContribution>,Iterable<R>> mapper,
                                                               SerializableSupplier<S> identitySupplier,
                                                               SerializableBiFunction<S,R,S> accumulator,
                                                               SerializableBinaryOperator<S> combiner)
                                                        throws Exception

Description copied from class: MapReducer

Generic "flat" version of the map-reduce used by the `OSMContributionView`, with by-osm-id grouped input to the `mapper` function.

Contrary to the "normal" map-reduce, the "flat" version adds the possibility to return any number of results in the `mapper` function. Additionally, this interface provides the `mapper` function with a list of all `OSMContribution`s of a particular OSM entity. This is used to do more complex analyses that require the full edit history of the respective OSM entities as input.

The combination of the used types and identity/reducer functions must make "mathematical" sense:

• the accumulator and combiner functions need to be associative,
• values generated by the identitySupplier factory must be an identity for the combiner function: `combiner(identitySupplier(),x)` must be equal to `x`,
• the combiner function must be compatible with the accumulator function: `combiner(u, accumulator(identitySupplier(), t)) == accumulator.apply(u, t)`

Functionally, this interface is similar to Java8 Stream's reduce(identity,accumulator,combiner) interface.

Overrides:

flatMapReduceCellsOSMContributionGroupedById in class MapReducer<X>

Type Parameters:

R - the data type returned by the `mapper` function

S - the data type used to contain the "reduced" (intermediate and final) results

Parameters:

mapper - a function that's called for all `OSMContribution`s of a particular OSM entity; returns a list of results (which can have any number of entries).

identitySupplier - a factory function that returns a new starting value to reduce results into (e.g. when summing values, one needs to start at zero)

accumulator - a function that takes a result from the `mapper` function (type <R>) and an accumulation value (type <S>, e.g. the result of `identitySupplier()`) and returns the "sum" of the two; contrary to `combiner`, this function is allowed to alter (mutate) the state of the accumulation value (e.g. directly adding new values to an existing Set object)

combiner - a function that calculates the "sum" of two <S> values; this function must be pure (have no side effects), and is not allowed to alter the state of the two input objects it gets!

Returns:

the result of the map-reduce operation, the final result of the last call to the `combiner` function, after all `mapper` results have been aggregated (in the `accumulator` and `combiner` steps)

Throws:

Exception

mapReduceCellsOSMEntitySnapshot

protected <R,S> S mapReduceCellsOSMEntitySnapshot(SerializableFunction<OSMEntitySnapshot,R> mapper,
                                                  SerializableSupplier<S> identitySupplier,
                                                  SerializableBiFunction<S,R,S> accumulator,
                                                  SerializableBinaryOperator<S> combiner)
                                           throws Exception

Description copied from class: MapReducer

Generic map-reduce used by the `OSMEntitySnapshotView`.

The combination of the used types and identity/reducer functions must make "mathematical" sense:

• the accumulator and combiner functions need to be associative,
• values generated by the identitySupplier factory must be an identity for the combiner function: `combiner(identitySupplier(),x)` must be equal to `x`,
• the combiner function must be compatible with the accumulator function: `combiner(u, accumulator(identitySupplier(), t)) == accumulator.apply(u, t)`

Functionally, this interface is similar to Java8 Stream's reduce(identity,accumulator,combiner) interface.

Overrides:

mapReduceCellsOSMEntitySnapshot in class MapReducer<X>

Type Parameters:

R - the data type returned by the `mapper` function

S - the data type used to contain the "reduced" (intermediate and final) results

Parameters:

mapper - a function that's called for each `OSMEntitySnapshot`

identitySupplier - a factory function that returns a new starting value to reduce results into (e.g. when summing values, one needs to start at zero)

accumulator - a function that takes a result from the `mapper` function (type <R>) and an accumulation value (type <S>, e.g. the result of `identitySupplier()`) and returns the "sum" of the two; contrary to `combiner`, this function is allowed to alter (mutate) the state of the accumulation value (e.g. directly adding new values to an existing Set object)

combiner - a function that calculates the "sum" of two <S> values; this function must be pure (have no side effects), and is not allowed to alter the state of the two input objects it gets!

Returns:

the result of the map-reduce operation, the final result of the last call to the `combiner` function, after all `mapper` results have been aggregated (in the `accumulator` and `combiner` steps)

Throws:

Exception

flatMapReduceCellsOSMEntitySnapshotGroupedById

protected <R,S> S flatMapReduceCellsOSMEntitySnapshotGroupedById(SerializableFunction<List<OSMEntitySnapshot>,Iterable<R>> mapper,
                                                                 SerializableSupplier<S> identitySupplier,
                                                                 SerializableBiFunction<S,R,S> accumulator,
                                                                 SerializableBinaryOperator<S> combiner)
                                                          throws Exception

Description copied from class: MapReducer

Generic "flat" version of the map-reduce used by the `OSMEntitySnapshotView`, with by-osm-id grouped input to the `mapper` function.

Contrary to the "normal" map-reduce, the "flat" version adds the possibility to return any number of results in the `mapper` function. Additionally, this interface provides the `mapper` function with a list of all `OSMContribution`s of a particular OSM entity. This is used to do more complex analyses that require the full list of snapshots of the respective OSM entities as input.

The combination of the used types and identity/reducer functions must make "mathematical" sense:

• the accumulator and combiner functions need to be associative,
• values generated by the identitySupplier factory must be an identity for the combiner function: `combiner(identitySupplier(),x)` must be equal to `x`,
• the combiner function must be compatible with the accumulator function: `combiner(u, accumulator(identitySupplier(), t)) == accumulator.apply(u, t)`

Functionally, this interface is similar to Java8 Stream's reduce(identity,accumulator,combiner) interface.

Overrides:

flatMapReduceCellsOSMEntitySnapshotGroupedById in class MapReducer<X>

Type Parameters:

R - the data type returned by the `mapper` function

S - the data type used to contain the "reduced" (intermediate and final) results

Parameters:

mapper - a function that's called for all `OSMEntitySnapshot`s of a particular OSM entity; returns a list of results (which can have any number of entries)

identitySupplier - a factory function that returns a new starting value to reduce results into (e.g. when summing values, one needs to start at zero)

accumulator - a function that takes a result from the `mapper` function (type <R>) and an accumulation value (type <S>, e.g. the result of `identitySupplier()`) and returns the "sum" of the two; contrary to `combiner`, this function is allowed to alter (mutate) the state of the accumulation value (e.g. directly adding new values to an existing Set object)

combiner - a function that calculates the "sum" of two <S> values; this function must be pure (have no side effects), and is not allowed to alter the state of the two input objects it gets!

Returns:

the result of the map-reduce operation, the final result of the last call to the `combiner` function, after all `mapper` results have been aggregated (in the `accumulator` and `combiner` steps)

Throws:

Exception

osmType

public M osmType(OSMType type1,
                 OSMType... otherTypes)

Limits the analysis to the given osm entity types.

Parameters:

type1 - the set of osm types to filter (e.g. `OSMType.NODE`)

otherTypes - more osm types which should be analyzed

Returns:

`this` mapReducer (can be used to chain multiple commands together)

osmTypes

@Deprecated
public M osmTypes(EnumSet<OSMType> typeFilter)

Deprecated. replaced by osmType(OSMType, OSMType...)

deprecated.

osmTypes

@Deprecated
public M osmTypes(OSMType type1,
                              OSMType... otherTypes)

Deprecated. replaced by osmType(OSMType, OSMType...)

deprecated.

where

@Deprecated
public M where(SerializablePredicate<OSMEntity> f)

Deprecated. replaced by osmEntityFilter(org.heigit.bigspatialdata.oshdb.api.generic.function.SerializablePredicate<org.heigit.bigspatialdata.oshdb.osm.OSMEntity>)

deprecated.

where

@Deprecated
public M where(OSMTagKey key)

Deprecated. replaced by osmTag(OSMTagInterface)

deprecated.

where

@Deprecated
public M where(String key)

Deprecated. replaced by osmTag(String)

deprecated.

where

@Deprecated
public M where(OSMTag tag)

Deprecated. replaced by osmTag(OSMTagInterface)

deprecated.

where

@Deprecated
public M where(String key,
                           String value)

Deprecated. replaced by osmTag(String, String)

deprecated.

where

@Deprecated
public M where(String key,
                           Collection<String> values)

Deprecated. replaced by osmTag(String, Collection)

deprecated.

where

@Deprecated
public M where(String key,
                           Pattern valuePattern)

Deprecated. replaced by osmTag(String, Pattern)

deprecated.

where

@Deprecated
public M where(Collection<OSMTag> keyValuePairs)

Deprecated. replaced by osmTag(Collection)

deprecated.