Package org.apache.lucene.search.suggest.document

Class ContextSuggestField

java.lang.Object

org.apache.lucene.document.Field

org.apache.lucene.search.suggest.document.SuggestField

org.apache.lucene.search.suggest.document.ContextSuggestField

All Implemented Interfaces:

IndexableField

public class ContextSuggestField
extends SuggestField

SuggestField which additionally takes in a set of contexts. Example usage of adding a suggestion with contexts is as follows:

  document.add(
   new ContextSuggestField(name, "suggestion", Arrays.asList("context1", "context2"),  4));
 

Use ContextQuery to boost and/or filter suggestions at query-time. Use PrefixCompletionQuery, RegexCompletionQuery or FuzzyCompletionQuery if context boost/filtering are not needed.

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

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.document.Field

Field.Store

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CONTEXT_SEPARATOR	Separator used between context value and the suggest field value

Fields inherited from class org.apache.lucene.search.suggest.document.SuggestField

FIELD_TYPE

Fields inherited from class org.apache.lucene.document.Field

fieldsData, name, tokenStream, type

Constructor Summary

Constructors

Constructor	Description
ContextSuggestField(String name, String value, int weight, CharSequence... contexts)	Creates a context-enabled suggest field

Method Summary

Modifier and Type	Method	Description
protected Iterable<CharSequence>	contexts()	Expert: Sub-classes can inject contexts at index-time
protected byte	type()	Returns a byte to denote the type of the field
protected CompletionTokenStream	wrapTokenStream(TokenStream stream)	Wraps a stream with a CompletionTokenStream.

Methods inherited from class org.apache.lucene.search.suggest.document.SuggestField

tokenStream

Methods inherited from class org.apache.lucene.document.Field

binaryValue, fieldType, getCharSequenceValue, name, numericValue, readerValue, setBytesValue, setBytesValue, setByteValue, setDoubleValue, setFloatValue, setIntValue, setLongValue, setReaderValue, setShortValue, setStringValue, setTokenStream, stringValue, tokenStreamValue, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

CONTEXT_SEPARATOR

public static final int CONTEXT_SEPARATOR

Separator used between context value and the suggest field value

See Also:

• Constant Field Values

Constructor Details

ContextSuggestField

public ContextSuggestField(String name,
 String value,
 int weight,
 CharSequence... contexts)

Creates a context-enabled suggest field

Parameters:

name - field name

value - field value to get suggestion on

weight - field weight

contexts - associated contexts

Throws:

IllegalArgumentException - if either the name or value is null, if value is an empty string, if the weight is negative, if value or contexts contains any reserved characters

Method Details

contexts

protected Iterable<CharSequence> contexts()

Expert: Sub-classes can inject contexts at index-time

wrapTokenStream

protected CompletionTokenStream wrapTokenStream(TokenStream stream)

Description copied from class: SuggestField

Wraps a stream with a CompletionTokenStream.

Subclasses can override this method to change the indexing pipeline.

Overrides:

wrapTokenStream in class SuggestField

type

protected byte type()

Description copied from class: SuggestField

Returns a byte to denote the type of the field

Overrides:

type in class SuggestField