public final class

NumericTokenStream

extends TokenStream
java.lang.Object
   ↳ org.apache.lucene.util.AttributeSource
     ↳ org.apache.lucene.analysis.TokenStream
       ↳ org.apache.lucene.analysis.NumericTokenStream

Class Overview

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

Note that for simple usage, NumericField is recommended. NumericField disables norms and term freqs, as they are not usually needed during searching. If you need to change these settings, you should use this class.

See NumericField for capabilities of fields indexed numerically.

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

  Field field = new Field(name, new NumericTokenStream(precisionStep).setIntValue(value));
  field.setOmitNorms(true);
  field.setOmitTermFreqAndPositions(true);
  document.add(field);
 

For optimal performance, re-use the TokenStream and Field instance for more than one document:

  NumericTokenStream stream = new NumericTokenStream(precisionStep);
  Field field = new Field(name, stream);
  field.setOmitNorms(true);
  field.setOmitTermFreqAndPositions(true);
  Document document = new Document();
  document.add(field);

  for(all documents) {
    stream.setIntValue(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.

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

Summary

Constants
String TOKEN_TYPE_FULL_PREC The full precision token gets this token type assigned.
String TOKEN_TYPE_LOWER_PREC The lower precision tokens gets this token type assigned.
Public Constructors
NumericTokenStream()
Creates a token stream for numeric values using the default precisionStep PRECISION_STEP_DEFAULT (4).
NumericTokenStream(int precisionStep)
Creates a token stream for numeric values with the specified precisionStep.
NumericTokenStream(AttributeSource source, int precisionStep)
Expert: Creates a token stream for numeric values with the specified precisionStep using the given AttributeSource.
NumericTokenStream(AttributeSource.AttributeFactory factory, int precisionStep)
Expert: Creates a token stream for numeric values with the specified precisionStep using the given AttributeSource.AttributeFactory.
Public Methods
boolean incrementToken()
Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.
void reset()
Resets this stream to the beginning.
NumericTokenStream setDoubleValue(double value)
Initializes the token stream with the supplied double value.
NumericTokenStream setFloatValue(float value)
Initializes the token stream with the supplied float value.
NumericTokenStream setIntValue(int value)
Initializes the token stream with the supplied int value.
NumericTokenStream setLongValue(long value)
Initializes the token stream with the supplied long value.
String toString()
[Expand]
Inherited Methods
From class org.apache.lucene.analysis.TokenStream
From class org.apache.lucene.util.AttributeSource
From class java.lang.Object
From interface java.io.Closeable

Constants

public static final String TOKEN_TYPE_FULL_PREC

The full precision token gets this token type assigned.

Constant Value: "fullPrecNumeric"

public static final String TOKEN_TYPE_LOWER_PREC

The lower precision tokens gets this token type assigned.

Constant Value: "lowerPrecNumeric"

Public Constructors

public NumericTokenStream ()

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

public NumericTokenStream (int precisionStep)

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.

public NumericTokenStream (AttributeSource source, int precisionStep)

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

public NumericTokenStream (AttributeSource.AttributeFactory factory, int precisionStep)

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.

Public Methods

public boolean 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 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 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(Class) and 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 incrementToken().

Returns
  • false for end of stream; true otherwise

public void reset ()

Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. reset() is not needed for the standard indexing process. However, if the tokens of a TokenStream are intended to be consumed more than once, it is necessary to implement reset(). Note that if your TokenStream caches tokens and feeds them back again after a reset, it is imperative that you clone the tokens when you store them away (on the first pass) as well as when you return them (on future passes after reset()).

public NumericTokenStream setDoubleValue (double value)

Initializes the token stream with the supplied double value.

Parameters
value the value, for which this TokenStream should enumerate tokens.
Returns
  • this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).setDoubleValue(value))

public NumericTokenStream setFloatValue (float value)

Initializes the token stream with the supplied float value.

Parameters
value the value, for which this TokenStream should enumerate tokens.
Returns
  • this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).setFloatValue(value))

public NumericTokenStream setIntValue (int value)

Initializes the token stream with the supplied int value.

Parameters
value the value, for which this TokenStream should enumerate tokens.
Returns
  • this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).setIntValue(value))

public NumericTokenStream setLongValue (long value)

Initializes the token stream with the supplied long value.

Parameters
value the value, for which this TokenStream should enumerate tokens.
Returns
  • this instance, because of this you can use it the following way: new Field(name, new NumericTokenStream(precisionStep).setLongValue(value))

public String toString ()