org.apache.lucene.facet.index.streaming
Class CategoryParentsStream

java.lang.Object
  org.apache.lucene.util.AttributeSource
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.TokenFilter
              org.apache.lucene.facet.index.streaming.CategoryParentsStream

All Implemented Interfaces:

Closeable

public class CategoryParentsStream
extends TokenFilter

This class adds parents to a CategoryAttributesStream. The parents are added according to the PathPolicy and OrdinalPolicy from the FacetIndexingParams given in the constructor.
By default, category properties are removed when creating parents of a certain category. However, it is possible to retain certain property types using addRetainableProperty(Class).

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

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

protected CategoryAttribute	categoryAttribute An attribute containing all data related to the category
protected OrdinalProperty	ordinalProperty A category property containing the category ordinal
protected TaxonomyWriter	taxonomyWriter A TaxonomyWriter for adding categories and retrieving their ordinals.

Fields inherited from class org.apache.lucene.analysis.TokenFilter

input

Constructor Summary

CategoryParentsStream(CategoryAttributesStream input, TaxonomyWriter taxonomyWriter, FacetIndexingParams indexingParams)
Constructor.

Method Summary

void	addRetainableProperty(Class<? extends CategoryProperty> toRetain) Add a CategoryProperty class which is retained when creating parent tokens.
protected void	clearCategoryProperties() Clear the properties of the current CategoryAttribute attribute before setting the parent attributes.
boolean	incrementToken() Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.

Methods inherited from class org.apache.lucene.analysis.TokenFilter

close, end, reset

Methods inherited from class org.apache.lucene.util.AttributeSource

addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString

Methods inherited from class java.lang.Object

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

Field Detail

taxonomyWriter

protected TaxonomyWriter taxonomyWriter

A TaxonomyWriter for adding categories and retrieving their ordinals.

categoryAttribute

protected CategoryAttribute categoryAttribute

An attribute containing all data related to the category

ordinalProperty

protected OrdinalProperty ordinalProperty

A category property containing the category ordinal

Constructor Detail

CategoryParentsStream

public CategoryParentsStream(CategoryAttributesStream input,
                             TaxonomyWriter taxonomyWriter,
                             FacetIndexingParams indexingParams)

Constructor.

Parameters:

input - The input stream to handle, must be derived from CategoryAttributesStream.

taxonomyWriter - The taxonomy writer to use for adding categories and retrieving their ordinals.

indexingParams - The indexing params used for filtering parents.

Method Detail

incrementToken

public final boolean incrementToken()
                             throws IOException

Description copied from class: TokenStream

Consumers (i.e., IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate AttributeImpls with the attributes of the next token.

The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use AttributeSource.captureState() to create a copy of the current attribute state.

This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to AttributeSource.addAttribute(Class) and AttributeSource.getAttribute(Class), references to all AttributeImpls that this stream uses should be retrieved during instantiation.

To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in TokenStream.incrementToken().

Specified by:

incrementToken in class TokenStream

Returns:

false for end of stream; true otherwise

Throws:

IOException

clearCategoryProperties

protected void clearCategoryProperties()

Clear the properties of the current CategoryAttribute attribute before setting the parent attributes.
It is possible to retain properties of certain types the parent tokens, using addRetainableProperty(Class).

addRetainableProperty

public void addRetainableProperty(Class<? extends CategoryProperty> toRetain)

Add a CategoryProperty class which is retained when creating parent tokens.

Parameters:

toRetain - The property class to retain.