org.apache.lucene.facet.index.params

Class CategoryListParams

java.lang.Object

org.apache.lucene.facet.index.params.CategoryListParams

All Implemented Interfaces:

Serializable

public class CategoryListParams
extends Object
implements Serializable

Contains parameters for a category list *

See Also:

Serialized Form

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

Field Summary

Fields

Modifier and Type	Field and Description
static Term	DEFAULT_TERM The default term used to store the facets information.

Constructor Summary

Constructors

Constructor and Description
CategoryListParams() Constructs a default category list parameters object, using DEFAULT_TERM.
CategoryListParams(Term term) Constructs a category list parameters object, using the given Term.

Method Summary

Methods

Modifier and Type	Method and Description
CategoryListIterator	createCategoryListIterator(IndexReader reader, int partition) Create the category list iterator for the specified partition.
IntEncoder	createEncoder() Allows to override how categories are encoded and decoded.
boolean	equals(Object o) Equality is defined by the 'term' that defines this category list.
Term	getTerm() A Term who's payload holds the category-list.
int	hashCode() Hashcode is similar to equals(Object), in that it uses the term that defines this category list to derive the hashcode.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_TERM

public static final Term DEFAULT_TERM

The default term used to store the facets information.

Constructor Detail

CategoryListParams

public CategoryListParams()

Constructs a default category list parameters object, using DEFAULT_TERM.

CategoryListParams

public CategoryListParams(Term term)

Constructs a category list parameters object, using the given Term.

Parameters:

term - who's payload hold the category-list.

Method Detail

getTerm

public final Term getTerm()

A Term who's payload holds the category-list.

createEncoder

public IntEncoder createEncoder()

Allows to override how categories are encoded and decoded. A matching IntDecoder is provided by the IntEncoder.

Default implementation creates a new Sorting(Unique(DGap)) encoder. Uniqueness in this regard means when the same category appears twice in a document, only one appearance would be encoded. This has effect on facet counting results.

Some possible considerations when overriding may be:

• an application "knows" that all categories are unique. So no need to pass through the unique filter.
• Another application might wish to count multiple occurrences of the same category, or, use a faster encoding which will consume more space.

In any event when changing this value make sure you know what you are doing, and test the results - e.g. counts, if the application is about counting facets.

equals

public boolean equals(Object o)

Equality is defined by the 'term' that defines this category list. Sub-classes should override this method if a more complex calculation is needed to ensure equality.

Overrides:

equals in class Object

hashCode

public int hashCode()

Hashcode is similar to equals(Object), in that it uses the term that defines this category list to derive the hashcode. Subclasses need to ensure that equality/hashcode is correctly defined, or there could be side-effects in the TotalFacetCounts caching mechanism (as the filename for a Total Facet Counts array cache is dependent on the hashCode, so it should consistently return the same hash for identity).

Overrides:

hashCode in class Object

createCategoryListIterator

public CategoryListIterator createCategoryListIterator(IndexReader reader,
                                              int partition)
                                                throws IOException

Create the category list iterator for the specified partition.

Throws:

IOException