org.apache.lucene.facet.search.params
Class FacetRequest

java.lang.Object
  org.apache.lucene.facet.search.params.FacetRequest

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

AssociationFloatSumFacetRequest, AssociationIntSumFacetRequest, CountFacetRequest, ScoreFacetRequest

public abstract class FacetRequest
extends Object
implements Cloneable

Request to accumulate facet information for a specified facet and possibly also some of its descendants, upto a specified depth.

The facet request additionally defines what information should be computed within the facet results, if and how should results be ordered, etc.

An example facet request is to look at all sub-categories of "Author", and return the 10 with the highest counts (sorted by decreasing count).

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

static class	FacetRequest.ResultMode Result structure manner of applying request's limits such as getNumLabel() and getNumResults().
static class	FacetRequest.SortBy Sort options for facet results.
static class	FacetRequest.SortOrder Requested sort order for the results.

Field Summary

static int	DEFAULT_DEPTH Default depth for facets accumulation.
static FacetRequest.ResultMode	DEFAULT_RESULT_MODE Default result mode
static FacetRequest.SortBy	DEFAULT_SORT_BY Default sort mode.

Constructor Summary

FacetRequest(CategoryPath path, int numResults)
Initialize the request with a given path, and a requested number of facets results.

Method Summary

Object	clone()
abstract Aggregator	createAggregator(boolean useComplements, FacetArrays arrays, IndexReader indexReader, TaxonomyReader taxonomy) Create an aggregator for this facet request.
CategoryListIterator	createCategoryListIterator(IndexReader reader, TaxonomyReader taxo, FacetSearchParams sParams, int partition) Create the category list iterator for the specified partition.
FacetResultsHandler	createFacetResultsHandler(TaxonomyReader taxonomyReader) Creates a new FacetResultsHandler that matches the request logic and current settings, such as depth, limits-mode, etc, as well as the passed in TaxonomyReader.
boolean	equals(Object o)
CategoryPath	getCategoryPath() The root category of this facet request.
int	getDepth() How deeply to look under the given category.
int	getNumLabel() If getNumLabel()
int	getNumResults() The number of sub-categories to return (at most).
FacetRequest.ResultMode	getResultMode() Return the requested result mode.
FacetRequest.SortBy	getSortBy() Specify how should results be sorted.
FacetRequest.SortOrder	getSortOrder() Return the requested order of results.
abstract double	getValueOf(FacetArrays arrays, int idx) Return the value of a category used for facets computations for this request.
int	hashCode()
abstract boolean	requireDocumentScore() Indicates whether the results of this request depends on each result document's score
void	setDepth(int depth)
void	setNumLabel(int numLabel)
void	setResultMode(FacetRequest.ResultMode resultMode)
void	setSortBy(FacetRequest.SortBy sortBy)
void	setSortOrder(FacetRequest.SortOrder sortOrder)
boolean	supportsComplements() Indicates whether this facet request is eligible for applying the complements optimization.
String	toString()

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_DEPTH

public static final int DEFAULT_DEPTH

Default depth for facets accumulation.

See Also:

getDepth(), Constant Field Values

DEFAULT_SORT_BY

public static final FacetRequest.SortBy DEFAULT_SORT_BY

Default sort mode.

See Also:

getSortBy()

DEFAULT_RESULT_MODE

public static final FacetRequest.ResultMode DEFAULT_RESULT_MODE

Default result mode

See Also:

getResultMode()

Constructor Detail

FacetRequest

public FacetRequest(CategoryPath path,
                    int numResults)

Initialize the request with a given path, and a requested number of facets results. By default, all returned results would be labeled - to alter this default see setNumLabel(int).

NOTE: if numResults is given as Integer.MAX_VALUE than all the facet results would be returned, without any limit.

NOTE: it is assumed that the given CategoryPath is not modified after construction of this object. Otherwise, some things may not function properly, e.g. hashCode().

Throws:

IllegalArgumentException - if numResults is ≤ 0

Method Detail

clone

public Object clone()
             throws CloneNotSupportedException

Overrides:

clone in class Object

Throws:

CloneNotSupportedException

setNumLabel

public void setNumLabel(int numLabel)

setDepth

public void setDepth(int depth)

setSortOrder

public void setSortOrder(FacetRequest.SortOrder sortOrder)

setSortBy

public void setSortBy(FacetRequest.SortBy sortBy)

getCategoryPath

public final CategoryPath getCategoryPath()

The root category of this facet request. The categories that are returned as a result of this request will all be descendants of this root.

NOTE: you should not modify the returned CategoryPath, or otherwise some methonds may not work properly, e.g. hashCode().

getDepth

public final int getDepth()

How deeply to look under the given category. If the depth is 0, only the category itself is counted. If the depth is 1, its immediate children are also counted, and so on. If the depth is Integer.MAX_VALUE, all the category's descendants are counted.
TODO (Facet): add AUTO_EXPAND option

getNumLabel

public final int getNumLabel()

If getNumLabel() If Integer.MAX_VALUE is specified, all results are labled.

The purpose of this parameter is to avoid having to run the whole faceted search again when the user asks for more values for the facet; The application can ask (getNumResults()) for more values than it needs to show, but keep getNumLabel() only the number it wants to immediately show. The slow-down caused by finding more values is negligible, because the slowest part - finding the categories' paths, is avoided.

Depending on the LimitsMode, this limit is applied globally or per results node. In the global mode, if this limit is 3, only 3 top results would be labeled. In the per-node mode, if this limit is 3, 3 top children of the target category would be labeled, as well as 3 top children of each of them, and so forth, until the depth defined by getDepth().

See Also:

getResultMode()

getNumResults

public final int getNumResults()

The number of sub-categories to return (at most). If the sub-categories are returned.

If Integer.MAX_VALUE is specified, all sub-categories are returned.

Depending on the LimitsMode, this limit is applied globally or per results node. In the global mode, if this limit is 3, only 3 top results would be computed. In the per-node mode, if this limit is 3, 3 top children of the target category would be returned, as well as 3 top children of each of them, and so forth, until the depth defined by getDepth().

See Also:

getResultMode()

getSortBy

public final FacetRequest.SortBy getSortBy()

Specify how should results be sorted.

getSortOrder

public final FacetRequest.SortOrder getSortOrder()

Return the requested order of results.

toString

public String toString()

Overrides:

toString in class Object

createFacetResultsHandler

public FacetResultsHandler createFacetResultsHandler(TaxonomyReader taxonomyReader)

Creates a new FacetResultsHandler that matches the request logic and current settings, such as depth, limits-mode, etc, as well as the passed in TaxonomyReader.

Parameters:

taxonomyReader - taxonomy reader is needed e.g. for knowing the taxonomy size.

getResultMode

public final FacetRequest.ResultMode getResultMode()

Return the requested result mode.

setResultMode

public void setResultMode(FacetRequest.ResultMode resultMode)

Parameters:

resultMode - the resultMode to set

See Also:

getResultMode()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object o)

Overrides:

equals in class Object

createAggregator

public abstract Aggregator createAggregator(boolean useComplements,
                                            FacetArrays arrays,
                                            IndexReader indexReader,
                                            TaxonomyReader taxonomy)
                                     throws IOException

Create an aggregator for this facet request. Aggregator action depends on request definition. For a count request, it will usually increment the count for that facet.

Parameters:

useComplements - whether the complements optimization is being used for current computation.

arrays - provider for facet arrays in use for current computation.

indexReader - index reader in effect.

taxonomy - reader of taxonomy in effect.

Throws:

IOException

createCategoryListIterator

public CategoryListIterator createCategoryListIterator(IndexReader reader,
                                                       TaxonomyReader taxo,
                                                       FacetSearchParams sParams,
                                                       int partition)
                                                throws IOException

Create the category list iterator for the specified partition. If a non null cache is provided which contains the required data, use it for the iteration.

Throws:

IOException

getValueOf

public abstract double getValueOf(FacetArrays arrays,
                                  int idx)

Return the value of a category used for facets computations for this request. For a count request this would be the count for that facet, i.e. an integer number. but for other requests this can be the result of a more complex operation, and the result can be any double precision number. Having this method with a general name value which is double precision allows to have more compact API and code for handling counts and perhaps other requests (such as for associations) very similarly, and by the same code and API, avoiding code duplication.

Parameters:

arrays - provider for facet arrays in use for current computation.

idx - an index into the count arrays now in effect in arrays. E.g., for ordinal number n, with partition, of size partitionSize, now covering n, getValueOf would be invoked with idx being n % partitionSize.

supportsComplements

public boolean supportsComplements()

Indicates whether this facet request is eligible for applying the complements optimization.

requireDocumentScore

public abstract boolean requireDocumentScore()

Indicates whether the results of this request depends on each result document's score