Package org.apache.lucene.search.suggest.analyzing

Class BlendedInfixSuggester

java.lang.Object

org.apache.lucene.search.suggest.Lookup

org.apache.lucene.search.suggest.analyzing.AnalyzingInfixSuggester

org.apache.lucene.search.suggest.analyzing.BlendedInfixSuggester

All Implemented Interfaces:

Closeable, AutoCloseable, Accountable

public class BlendedInfixSuggester
extends AnalyzingInfixSuggester

Extension of the AnalyzingInfixSuggester which transforms the weight after search to take into account the position of the searched term into the indexed text. Please note that it increases the number of elements searched and applies the ponderation after. It might be costly for long suggestions.

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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	BlendedInfixSuggester.BlenderType	The different types of blender.

Nested classes/interfaces inherited from class org.apache.lucene.search.suggest.Lookup

Lookup.LookupPriorityQueue, Lookup.LookupResult

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_NUM_FACTOR	Default factor
protected static double	LINEAR_COEF	Coefficient used for linear blending

Fields inherited from class org.apache.lucene.search.suggest.analyzing.AnalyzingInfixSuggester

CONTEXTS_FIELD_NAME, DEFAULT_ALL_TERMS_REQUIRED, DEFAULT_CLOSE_INDEXWRITER_ON_BUILD, DEFAULT_HIGHLIGHT, DEFAULT_MIN_PREFIX_CHARS, EXACT_TEXT_FIELD_NAME, indexAnalyzer, queryAnalyzer, searcherMgr, searcherMgrLock, TEXT_FIELD_NAME, TEXTGRAMS_FIELD_NAME, writer

Fields inherited from class org.apache.lucene.search.suggest.Lookup

CHARSEQUENCE_COMPARATOR

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Constructor	Description
BlendedInfixSuggester(Directory dir, Analyzer analyzer)	Create a new instance, loading from a previously built directory, if it exists.
BlendedInfixSuggester(Directory dir, Analyzer indexAnalyzer, Analyzer queryAnalyzer, int minPrefixChars, BlendedInfixSuggester.BlenderType blenderType, int numFactor, boolean commitOnBuild)	Create a new instance, loading from a previously built directory, if it exists.
BlendedInfixSuggester(Directory dir, Analyzer indexAnalyzer, Analyzer queryAnalyzer, int minPrefixChars, BlendedInfixSuggester.BlenderType blenderType, int numFactor, Double exponent, boolean commitOnBuild, boolean allTermsRequired, boolean highlight)	Create a new instance, loading from a previously built directory, if it exists.

Method Summary

Modifier and Type	Method	Description
protected double	calculateCoefficient(int position)	Calculate the weight coefficient based on the position of the first matching word.
protected List<Lookup.LookupResult>	createResults(IndexSearcher searcher, TopFieldDocs hits, int num, CharSequence key, boolean doHighlight, Set<String> matchedTokens, String prefixToken)	Create the results based on the search hits.
protected FieldType	getTextFieldType()	Subclass can override this method to change the field type of the text field e.g.
List<Lookup.LookupResult>	lookup(CharSequence key, Map<BytesRef,BooleanClause.Occur> contextInfo, int num, boolean allTermsRequired, boolean doHighlight)	Retrieve suggestions, specifying whether all terms must match (allTermsRequired) and whether the hits should be highlighted (doHighlight).
List<Lookup.LookupResult>	lookup(CharSequence key, Set<BytesRef> contexts, boolean onlyMorePopular, int num)	Look up a key and return possible completion for this key.
List<Lookup.LookupResult>	lookup(CharSequence key, Set<BytesRef> contexts, int num, boolean allTermsRequired, boolean doHighlight)	Lookup, with context but without booleans.
List<Lookup.LookupResult>	lookup(CharSequence key, BooleanQuery contextQuery, int num, boolean allTermsRequired, boolean doHighlight)	This is an advanced method providing the capability to send down to the suggester any arbitrary lucene query to be used to filter the result of the suggester

Methods inherited from class org.apache.lucene.search.suggest.analyzing.AnalyzingInfixSuggester

add, addContextToQuery, addNonMatch, addPrefixMatch, addWholeMatch, build, close, commit, finishQuery, getCount, getDirectory, getIndexWriterConfig, getLastTokenQuery, highlight, load, lookup, ramBytesUsed, refresh, store, update

Methods inherited from class org.apache.lucene.search.suggest.Lookup

build, load, lookup, store

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Field Details

LINEAR_COEF

protected static double LINEAR_COEF

Coefficient used for linear blending

DEFAULT_NUM_FACTOR

public static int DEFAULT_NUM_FACTOR

Default factor

Constructor Details

BlendedInfixSuggester

public BlendedInfixSuggester(Directory dir,
 Analyzer analyzer)
                      throws IOException

Create a new instance, loading from a previously built directory, if it exists.

Throws:

IOException

BlendedInfixSuggester

public BlendedInfixSuggester(Directory dir,
 Analyzer indexAnalyzer,
 Analyzer queryAnalyzer,
 int minPrefixChars,
 BlendedInfixSuggester.BlenderType blenderType,
 int numFactor,
 boolean commitOnBuild)
                      throws IOException

Create a new instance, loading from a previously built directory, if it exists.

Parameters:

blenderType - Type of blending strategy, see BlenderType for more precisions

numFactor - Factor to multiply the number of searched elements before ponderate

commitOnBuild - Call commit after the index has finished building. This would persist the suggester index to disk and future instances of this suggester can use this pre-built dictionary.

Throws:

IOException - If there are problems opening the underlying Lucene index.

BlendedInfixSuggester

public BlendedInfixSuggester(Directory dir,
 Analyzer indexAnalyzer,
 Analyzer queryAnalyzer,
 int minPrefixChars,
 BlendedInfixSuggester.BlenderType blenderType,
 int numFactor,
 Double exponent,
 boolean commitOnBuild,
 boolean allTermsRequired,
 boolean highlight)
                      throws IOException

Create a new instance, loading from a previously built directory, if it exists.

Parameters:

blenderType - Type of blending strategy, see BlenderType for more precisions

numFactor - Factor to multiply the number of searched elements before ponderate

exponent - exponent used only when blenderType is BlenderType.POSITION_EXPONENTIAL_RECIPROCAL

commitOnBuild - Call commit after the index has finished building. This would persist the suggester index to disk and future instances of this suggester can use this pre-built dictionary.

allTermsRequired - All terms in the suggest query must be matched.

highlight - Highlight suggest query in suggestions.

Throws:

IOException - If there are problems opening the underlying Lucene index.

Method Details

lookup

public List<Lookup.LookupResult> lookup(CharSequence key,
 Set<BytesRef> contexts,
 boolean onlyMorePopular,
 int num)
                                 throws IOException

Description copied from class: Lookup

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

Overrides:

lookup in class AnalyzingInfixSuggester

Parameters:

key - lookup key. Depending on the implementation this may be a prefix, misspelling, or even infix.

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

onlyMorePopular - return only more popular results

num - maximum number of results to return

Returns:

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

Throws:

IOException

lookup

public List<Lookup.LookupResult> lookup(CharSequence key,
 Set<BytesRef> contexts,
 int num,
 boolean allTermsRequired,
 boolean doHighlight)
                                 throws IOException

Description copied from class: AnalyzingInfixSuggester

Lookup, with context but without booleans. Context booleans default to SHOULD, so each suggestion must have at least one of the contexts.

Overrides:

lookup in class AnalyzingInfixSuggester

Throws:

IOException

lookup

public List<Lookup.LookupResult> lookup(CharSequence key,
 Map<BytesRef,BooleanClause.Occur> contextInfo,
 int num,
 boolean allTermsRequired,
 boolean doHighlight)
                                 throws IOException

Description copied from class: AnalyzingInfixSuggester

Retrieve suggestions, specifying whether all terms must match (allTermsRequired) and whether the hits should be highlighted (doHighlight).

Overrides:

lookup in class AnalyzingInfixSuggester

Throws:

IOException

lookup

public List<Lookup.LookupResult> lookup(CharSequence key,
 BooleanQuery contextQuery,
 int num,
 boolean allTermsRequired,
 boolean doHighlight)
                                 throws IOException

Description copied from class: AnalyzingInfixSuggester

This is an advanced method providing the capability to send down to the suggester any arbitrary lucene query to be used to filter the result of the suggester

Overrides:

lookup in class AnalyzingInfixSuggester

Parameters:

key - the keyword being looked for

contextQuery - an arbitrary Lucene query to be used to filter the result of the suggester. AnalyzingInfixSuggester.addContextToQuery(org.apache.lucene.search.BooleanQuery.Builder, org.apache.lucene.util.BytesRef, org.apache.lucene.search.BooleanClause.Occur) could be used to build this contextQuery.

num - number of items to return

allTermsRequired - all searched terms must match or not

doHighlight - if true, the matching term will be highlighted in the search result

Returns:

the result of the suggester

Throws:

IOException - f the is IO exception while reading data from the index

getTextFieldType

protected FieldType getTextFieldType()

Description copied from class: AnalyzingInfixSuggester

Subclass can override this method to change the field type of the text field e.g. to change the index options

Overrides:

getTextFieldType in class AnalyzingInfixSuggester

createResults

protected List<Lookup.LookupResult> createResults(IndexSearcher searcher,
 TopFieldDocs hits,
 int num,
 CharSequence key,
 boolean doHighlight,
 Set<String> matchedTokens,
 String prefixToken)
                                           throws IOException

Description copied from class: AnalyzingInfixSuggester

Create the results based on the search hits. Can be overridden by subclass to add particular behavior (e.g. weight transformation). Note that there is no prefix token (the prefixToken argument will be null) whenever the final token in the incoming request was in fact finished (had trailing characters, such as white-space).

Overrides:

createResults in class AnalyzingInfixSuggester

Throws:

IOException - If there are problems reading fields from the underlying Lucene index.

calculateCoefficient

protected double calculateCoefficient(int position)

Calculate the weight coefficient based on the position of the first matching word. Subclass should override it to adapt it to particular needs

Parameters:

position - of the first matching word in text

Returns:

the coefficient