public class TopKInEachNodeHandler extends FacetResultsHandler
FacetResultfrom the count arrays aggregated for a particular
FacetRequest. The generated
FacetResultis a subtree of the taxonomy tree. Its root node,
FacetResult.getFacetResultNode(), is the facet specified by
FacetRequest.getCategoryPath(), and the enumerated children,
FacetResultNode.getSubResults(), of each node in that
FacetResultare the top K ( =
FacetRequest.getNumResults()) among its children in the taxonomy. Top in the sense
FacetRequest.getSortBy(), which can be by the values aggregated in the count arrays, or by ordinal numbers; also specified is the sort order,
FacetRequest.getSortOrder(), ascending or descending, of these values or ordinals before their top K are selected. The depth (number of levels excluding the root) of the
FacetResulttree is specified by
Because the number of selected children of each node is restricted,
and not the overall number of nodes in the
FacetResult, facets not selected
FacetResult might have better values, or ordinals, (typically,
higher counts), than facets that are selected into the
FacetResult also provides with
FacetResult.getNumValidDescendants(), which returns the total number of facets
that are descendants of the root node, no deeper than
which have valid value. The rootnode itself is not counted here.
Valid value is determined by the
TopKInEachNodeHandler defines valid as != 0.
NOTE: this code relies on the assumption that
TaxonomyReader.INVALID_ORDINAL == -1, a smaller
value than any valid ordinal.
|Modifier and Type||Class and Description|
Maintains an array of
Intermediate result to hold counts from one or more partitions processed thus far.
|Constructor and Description|
|Modifier and Type||Method and Description|
Recursively explore all facets that can be potentially included in the
Merge several partitions'
Perform any rearrangement as required on a facet result that has changed after it was rendered.
Create a facet result from the temporary result.
getFacetRequest, getTaxonomyReader, isSelfPartition
public IntermediateFacetResult fetchPartitionResult(FacetArrays arrays, int offset) throws IOException
FacetResultto be generated, and that belong to the given partition, so that values can be examined and collected. For each such node, gather its top K (
FacetRequest.getNumResults()) children among its children that are encountered in the given particular partition (aka current counting list).
arrays- the already filled in count array, potentially only covering one partition: the ordinals ranging from
offset+ the length of the count arrays within
IntToObjectMapthat maps potential
FacetResultnodes to their top K children encountered in the current partition. Note that the mapped potential tree nodes need not belong to the given partition, only the top K children mapped to. The aim is to identify nodes that are certainly excluded from the
FacetResultto be eventually (after going through all the partitions) returned by this handler, because they have K better siblings, already identified in this partition. For the identified excluded nodes, we only count number of their descendants in the subtree (to be included in
FacetResult.getNumValidDescendants()), but not bother with selecting top K in these generations, which, by definition, are, too, excluded from the FacetResult tree.
IOException- in case
public IntermediateFacetResult mergeResults(IntermediateFacetResult... tmpResults) throws ClassCastException, IllegalArgumentException
IntermediateFacetResult-s into one of the same format
tmpResults- one or more temporary results created by this handler.
ClassCastException- if the temporary result passed was not created by this handler
IllegalArgumentException- if passed
facetResultsdo not have the same
public void labelResult(FacetResult facetResult) throws IOException
FacetRequest, such as
FacetRequest.getNumLabel(). Usually invoked by
public FacetResult rearrangeFacetResult(FacetResult facetResult)
Possible use case: a sampling facets accumulator invoked another other facets accumulator on a sample set of documents, obtained rendered facet results, fixed their counts, and now it is needed to sort the results differently according to the fixed counts.
public FacetResult renderFacetResult(IntermediateFacetResult tmpResult) throws IOException
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