org.apache.lucene.analysis

Class NumericTokenStream

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.NumericTokenStream

All Implemented Interfaces:

Closeable

public final class NumericTokenStream
extends TokenStream

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.setIndexOptions(IndexOptions.DOCS_ONLY);
  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.setIndexOptions(IndexOptions.DOCS_ONLY);
  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.

Since:

2.9

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

Fields

Modifier and Type	Field and Description
static String	TOKEN_TYPE_FULL_PREC The full precision token gets this token type assigned.
static String	TOKEN_TYPE_LOWER_PREC The lower precision tokens gets this token type assigned.

Constructor Summary

Constructors

Constructor and Description
NumericTokenStream() Creates a token stream for numeric values using the default precisionStep NumericUtils.PRECISION_STEP_DEFAULT (4).
NumericTokenStream(AttributeSource.AttributeFactory factory, int precisionStep) Expert: Creates a token stream for numeric values with the specified precisionStep using the given AttributeSource.AttributeFactory.
NumericTokenStream(AttributeSource source, int precisionStep) Expert: Creates a token stream for numeric values with the specified precisionStep using the given AttributeSource.
NumericTokenStream(int precisionStep) Creates a token stream for numeric values with the specified precisionStep.

Method Summary

Methods

Modifier and Type	Method and Description
int	getPrecisionStep() Returns the precision step.
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() Returns a string representation of the object.

Methods inherited from class org.apache.lucene.analysis.TokenStream

close, end

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

Methods inherited from class java.lang.Object

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

Field Detail

TOKEN_TYPE_FULL_PREC

public static final String TOKEN_TYPE_FULL_PREC

The full precision token gets this token type assigned.

See Also:

Constant Field Values

TOKEN_TYPE_LOWER_PREC

public static final String TOKEN_TYPE_LOWER_PREC

The lower precision tokens gets this token type assigned.

See Also:

Constant Field Values

Constructor Detail

NumericTokenStream

public NumericTokenStream()

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

NumericTokenStream

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.

NumericTokenStream

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.

NumericTokenStream

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.

Method Detail

setLongValue

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))

setIntValue

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))

setDoubleValue

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))

setFloatValue

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))

reset

public void reset()

Description copied from class: TokenStream

Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. TokenStream.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 TokenStream.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 TokenStream.reset()).

Overrides:

reset in class TokenStream

incrementToken

public boolean incrementToken()

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 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 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) and AttributeSource.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 TokenStream.incrementToken().

Specified by:

incrementToken in class TokenStream

Returns:

false for end of stream; true otherwise

toString

public String toString()

Description copied from class: AttributeSource

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object.

WARNING: For backwards compatibility this method is implemented as in Lucene 2.9/3.0. In Lucene 4.0 this default implementation will be removed.

It is recommeneded to use AttributeSource.reflectAsString(boolean) or AttributeSource.reflectWith(org.apache.lucene.util.AttributeReflector) to get a well-defined output of AttributeSource's internals.

Overrides:

toString in class AttributeSource

getPrecisionStep

public int getPrecisionStep()

Returns the precision step.