Class NumericTokenStream

Expert: this class provides a TokenStream for indexing numeric values that can be used by NumericRangeQuery or NumericRangeFilter.

Note that for simple usage, Int32Field, Int64Field, SingleField or DoubleField is recommended. These fields disable norms and term freqs, as they are not usually needed during searching. If you need to change these settings, you should use this class.

Here's an example usage, for an int field:

IndexableFieldType fieldType = new IndexableFieldType(TextField.TYPE_NOT_STORED)
 {
     OmitNorms = true,
     IndexOptions = IndexOptions.DOCS_ONLY
 };
 Field field = new Field(name, new NumericTokenStream(precisionStep).SetInt32Value(value), fieldType);
 document.Add(field);

For optimal performance, re-use the TokenStream and Field instance

for more than one document:

NumericTokenStream stream = new NumericTokenStream(precisionStep);
 IndexableFieldType fieldType = new IndexableFieldType(TextField.TYPE_NOT_STORED)
 {
     OmitNorms = true,
     IndexOptions = IndexOptions.DOCS_ONLY
 };
 Field field = new Field(name, stream, fieldType);
 Document document = new Document();
 document.Add(field);

 for(all documents) 
 {
     stream.SetInt32Value(value)
     writer.AddDocument(document);
 }

this stream is not intended to be used in analyzers;

it's more for iterating the different precisions during indexing a specific numeric value.

NOTE: as token streams are only consumed once the document is added to the index, if you index more than one numeric field, use a separate NumericTokenStream instance for each.

See NumericRangeQuery for more details on the precisionStep parameter as well as how numeric fields work under the hood.

@since 2.9

Inheritance

object

AttributeSource

TokenStream

NumericTokenStream

Implements

IDisposable

Inherited Members

TokenStream.End()

TokenStream.Dispose()

AttributeSource.GetAttributeFactory()

AttributeSource.GetAttributeClassesEnumerator()

AttributeSource.GetAttributeImplsEnumerator()

AttributeSource.AddAttributeImpl(Attribute)

AttributeSource.AddAttribute<T>()

AttributeSource.HasAttributes

AttributeSource.HasAttribute<T>()

AttributeSource.GetAttribute<T>()

AttributeSource.ClearAttributes()

AttributeSource.CaptureState()

AttributeSource.RestoreState(AttributeSource.State)

AttributeSource.GetHashCode()

AttributeSource.Equals(object)

AttributeSource.ReflectAsString(bool)

AttributeSource.ReflectWith(IAttributeReflector)

AttributeSource.CloneAttributes()

AttributeSource.CopyTo(AttributeSource)

AttributeSource.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Lucene.Net.Analysis

Assembly: Lucene.Net.dll

Syntax

public sealed class NumericTokenStream : TokenStream, IDisposable

Constructors

NumericTokenStream()

Creates a token stream for numeric values using the default precisionStepPRECISION_STEP_DEFAULT (4). The stream is not yet initialized, before using set a value using the various Set???Value() methods.

Declaration

public NumericTokenStream()

NumericTokenStream(AttributeFactory, int)

Expert: Creates a token stream for numeric values with the specified precisionStep using the given AttributeSource.AttributeFactory. The stream is not yet initialized, before using set a value using the various Set???Value() methods.

Declaration

public NumericTokenStream(AttributeSource.AttributeFactory factory, int precisionStep)

Parameters

Type	Name	Description
AttributeSource.AttributeFactory	factory
int	precisionStep

NumericTokenStream(int)

Creates a token stream for numeric values with the specified precisionStep. The stream is not yet initialized, before using set a value using the various Set???Value() methods.

Declaration

public NumericTokenStream(int precisionStep)

Parameters

Type	Name	Description
int	precisionStep

Fields

TOKEN_TYPE_FULL_PREC

The full precision token gets this token type assigned.

Declaration

public const string TOKEN_TYPE_FULL_PREC = "fullPrecNumeric"

Field Value

Type	Description
string

TOKEN_TYPE_LOWER_PREC

The lower precision tokens gets this token type assigned.

Declaration

public const string TOKEN_TYPE_LOWER_PREC = "lowerPrecNumeric"

Field Value

Type	Description
string

Properties

PrecisionStep

Returns the precision step.

Declaration

public int PrecisionStep { get; }

Property Value

Type	Description
int

Methods

IncrementToken()

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 IAttributes 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 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 AddAttribute<T>() and GetAttribute<T>(), references to all IAttributes 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 IncrementToken().

Declaration

public override bool IncrementToken()

Returns

Type	Description
bool	false for end of stream; true otherwise

Overrides

TokenStream.IncrementToken()

Reset()

This method is called by a consumer before it begins consumption using IncrementToken().

Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.

If you override this method, always call base.Reset(), otherwise some internal state will not be correctly reset (e.g., Tokenizer will throw InvalidOperationException on further usage).

Declaration

public override void Reset()

Overrides

TokenStream.Reset()

SetDoubleValue(double)

Initializes the token stream with the supplied double value.

Declaration

public NumericTokenStream SetDoubleValue(double value)

Parameters

Type	Name	Description
double	value	the value, for which this TokenStream should enumerate tokens.

Returns

Type	Description
NumericTokenStream	this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).SetDoubleValue(value))

SetInt32Value(int)

Initializes the token stream with the supplied int value.

NOTE: This was setIntValue() in Lucene

Declaration

public NumericTokenStream SetInt32Value(int value)

Parameters

Type	Name	Description
int	value	the value, for which this TokenStream should enumerate tokens.

Returns

Type	Description
NumericTokenStream	this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).SetInt32Value(value))

SetInt64Value(long)

Initializes the token stream with the supplied long value.

NOTE: This was setLongValue() in Lucene

Declaration

public NumericTokenStream SetInt64Value(long value)

Parameters

Type	Name	Description
long	value	the value, for which this TokenStream should enumerate tokens.

Returns

Type	Description
NumericTokenStream	this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).SetInt64Value(value))

SetSingleValue(float)

Initializes the token stream with the supplied float value.

NOTE: This was setFloatValue() in Lucene

Declaration

public NumericTokenStream SetSingleValue(float value)

Parameters

Type	Name	Description
float	value	the value, for which this TokenStream should enumerate tokens.

Returns

Type	Description
NumericTokenStream	this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).SetSingleValue(value))

Implements

IDisposable