Class CategoryParentsStream
- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.TokenFilter
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- org.apache.lucene.facet.index.streaming.CategoryParentsStream
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public class CategoryParentsStream extends TokenFilter
This class adds parents to aCategoryAttributesStream
. The parents are added according to thePathPolicy
andOrdinalPolicy
from theFacetIndexingParams
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 usingaddRetainableProperty(Class)
.- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.AttributeFactory, AttributeSource.State
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Field Summary
Fields Modifier and Type Field Description protected CategoryAttribute
categoryAttribute
An attribute containing all data related to the categoryprotected OrdinalProperty
ordinalProperty
A category property containing the category ordinalprotected TaxonomyWriter
taxonomyWriter
ATaxonomyWriter
for adding categories and retrieving their ordinals.-
Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
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Constructor Summary
Constructors Constructor Description CategoryParentsStream(CategoryAttributesStream input, TaxonomyWriter taxonomyWriter, FacetIndexingParams indexingParams)
Constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addRetainableProperty(Class<? extends CategoryProperty> toRetain)
Add aCategoryProperty
class which is retained when creating parent tokens.protected void
clearCategoryProperties()
Clear the properties of the currentCategoryAttribute
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
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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
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Field Detail
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taxonomyWriter
protected TaxonomyWriter taxonomyWriter
ATaxonomyWriter
for adding categories and retrieving their ordinals.
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categoryAttribute
protected CategoryAttribute categoryAttribute
An attribute containing all data related to the category
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ordinalProperty
protected OrdinalProperty ordinalProperty
A category property containing the category ordinal
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Constructor Detail
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CategoryParentsStream
public CategoryParentsStream(CategoryAttributesStream input, TaxonomyWriter taxonomyWriter, FacetIndexingParams indexingParams)
Constructor.- Parameters:
input
- The input stream to handle, must be derived fromCategoryAttributesStream
.taxonomyWriter
- The taxonomy writer to use for adding categories and retrieving their ordinals.indexingParams
- The indexing params used for filtering parents.
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Method Detail
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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 appropriateAttributeImpl
s 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)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
s 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 classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
IOException
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clearCategoryProperties
protected void clearCategoryProperties()
Clear the properties of the currentCategoryAttribute
attribute before setting the parent attributes.
It is possible to retain properties of certain types the parent tokens, usingaddRetainableProperty(Class)
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addRetainableProperty
public void addRetainableProperty(Class<? extends CategoryProperty> toRetain)
Add aCategoryProperty
class which is retained when creating parent tokens.- Parameters:
toRetain
- The property class to retain.
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