org.apache.lucene.facet.enhancements
Interface CategoryEnhancement

All Known Implementing Classes:

AssociationEnhancement

public interface CategoryEnhancement

This interface allows easy addition of enhanced category features. Usually, a CategoryEnhancement will correspond to a CategoryProperty.

A category enhancement can contribute to the index in two possible ways:

1. To each category with data relevant to the enhancement, add this data to the category's token payload, through getCategoryTokenBytes(CategoryAttribute). This data will be read during search using extractCategoryTokenData(byte[], int, int).
2. To each document which contains categories with data relevant to the enhancement, add a CategoryListTokenizer through getCategoryListTokenizer(TokenStream, EnhancementsIndexingParams, TaxonomyWriter) . The CategoryListTokenizer should add a single token which includes all the enhancement relevant data from the categories. The category list token's text is defined by getCategoryListTermText().

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

Method Summary

Object	extractCategoryTokenData(byte[] buffer, int offset, int length) Get the data of this enhancement from a category token payload.
boolean	generatesCategoryList() Declarative method to indicate whether this enhancement generates separate category list.
String	getCategoryListTermText() Returns the text of this enhancement's category list term.
CategoryListTokenizer	getCategoryListTokenizer(org.apache.lucene.analysis.TokenStream tokenizer, EnhancementsIndexingParams indexingParams, TaxonomyWriter taxonomyWriter) Get the CategoryListTokenizer which generates the category list for this enhancement.
byte[]	getCategoryTokenBytes(CategoryAttribute categoryAttribute) Get the bytes to be added to the category token payload for this enhancement.
Class<? extends CategoryProperty>	getRetainableProperty() Get a CategoryProperty class to be retained when creating CategoryParentsStream.

Method Detail

getCategoryTokenBytes

byte[] getCategoryTokenBytes(CategoryAttribute categoryAttribute)

Get the bytes to be added to the category token payload for this enhancement.

NOTE: The returned array is copied, it is recommended to allocate a new one each time.

The bytes generated by this method are the input of extractCategoryTokenData(byte[], int, int).

Parameters:

categoryAttribute - The attribute of the category.

Returns:

The bytes to be added to the category token payload for this enhancement.

extractCategoryTokenData

Object extractCategoryTokenData(byte[] buffer,
                                int offset,
                                int length)

Get the data of this enhancement from a category token payload.

The input bytes for this method are generated in getCategoryTokenBytes(CategoryAttribute).

Parameters:

buffer - The payload buffer.

offset - The offset of this enhancement's data in the buffer.

length - The length of this enhancement's data (bytes).

Returns:

An Object containing the data.

generatesCategoryList

boolean generatesCategoryList()

Declarative method to indicate whether this enhancement generates separate category list.

Returns:

true if generates category list, else false.

getCategoryListTermText

String getCategoryListTermText()

Returns the text of this enhancement's category list term.

Returns:

The text of this enhancement's category list term.

getCategoryListTokenizer

CategoryListTokenizer getCategoryListTokenizer(org.apache.lucene.analysis.TokenStream tokenizer,
                                               EnhancementsIndexingParams indexingParams,
                                               TaxonomyWriter taxonomyWriter)

Get the CategoryListTokenizer which generates the category list for this enhancement. If generatesCategoryList() returns false this method will not be called.

Parameters:

tokenizer - The input stream containing categories.

indexingParams - The indexing params to use.

taxonomyWriter - The taxonomy to add categories and get their ordinals.

Returns:

A CategoryListTokenizer generating the category list for this enhancement, with tokenizer as it's input.

getRetainableProperty

Class<? extends CategoryProperty> getRetainableProperty()

Get a CategoryProperty class to be retained when creating CategoryParentsStream.

Returns:

the CategoryProperty class to be retained when creating CategoryParentsStream, or null if there is no such property.