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(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(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.