Class WFSTCompletionLookup

Suggester based on a weighted FST: it first traverses the prefix, then walks the n shortest paths to retrieve top-ranked suggestions.

NOTE: Input weights must be between 0 and MaxValue, any other values will be rejected.

Note

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

Inheritance
object
Lookup
WFSTCompletionLookup
Inherited Members
Namespace: Lucene.Net.Search.Suggest.Fst
Assembly: Lucene.Net.Suggest.dll
Syntax
public class WFSTCompletionLookup : Lookup

Constructors

WFSTCompletionLookup()

Calls WFSTCompletionLookup(true)

Declaration
public WFSTCompletionLookup()

WFSTCompletionLookup(bool)

Creates a new suggester.

Declaration
public WFSTCompletionLookup(bool exactFirst)
Parameters
Type Name Description
bool exactFirst 
true
if suggestions that match the 
   prefix exactly should always be returned first, regardless
   of score. This has no performance impact, but could result
   in low-quality suggestions.

Properties

Count

Get the number of entries the lookup was built with

Declaration
public override long Count { get; }
Property Value
Type Description
long

total number of suggester entries
Overrides

Methods

Build(IInputEnumerator)

Builds up a new internal Lookup representation based on the given IInputEnumerator. The implementation might re-sort the data internally.

Declaration
public override void Build(IInputEnumerator enumerator)
Parameters
Type Name Description
IInputEnumerator enumerator
Overrides

DoLookup(string, IEnumerable<BytesRef>, bool, int)

Look up a key and return possible completion for this key.

Declaration
public override IList<Lookup.LookupResult> DoLookup(string key, IEnumerable<BytesRef> contexts, bool onlyMorePopular, int num)
Parameters
Type Name Description
string key

lookup key. Depending on the implementation this may be a prefix, misspelling, or even infix.
IEnumerable<BytesRef> contexts

contexts to filter the lookup by, or null if all contexts are allowed; if the suggestion contains any of the contexts, it's a match
bool onlyMorePopular

return only more popular results
int num

maximum number of results to return
Returns
Type Description
IList<Lookup.LookupResult>

a list of possible completions, with their relative weight (e.g. popularity)
Overrides

Get(string)

Returns the weight associated with an input string, or null if it does not exist.

Declaration
public virtual long? Get(string key)
Parameters
Type Name Description
string key
Returns
Type Description
long?

GetSizeInBytes()

Returns byte size of the underlying FST.

Declaration
public override long GetSizeInBytes()
Returns
Type Description
long
Overrides

Load(DataInput)

Discard current lookup data and load it from a previously saved copy. Optional operation.

Declaration
public override bool Load(DataInput input)
Parameters
Type Name Description
DataInput input

the Lucene.Net.Store.DataInput to load the lookup data.
Returns
Type Description
bool

true if completed successfully, false if unsuccessful or not supported.
Overrides
Exceptions
Type Condition
IOException

when fatal IO error occurs.

Store(DataOutput)

Persist the constructed lookup data to a directory. Optional operation.

Declaration
public override bool Store(DataOutput output)
Parameters
Type Name Description
DataOutput output

Lucene.Net.Store.DataOutput to write the data to.
Returns
Type Description
bool

true if successful, false if unsuccessful or not supported.
Overrides
Exceptions
Type Condition
IOException

when fatal IO error occurs.