Package com.yahoo.search.query.rewrite

Class RewriterFeatures

java.lang.Object

com.yahoo.search.query.rewrite.RewriterFeatures

public class RewriterFeatures
extends Object

Contains commonly used rewriter features

Author:

Karen Sze Wing Lee

Constructor Summary

Constructors

Constructor	Description
RewriterFeatures()

Method Summary

Modifier and Type	Method	Description
static Query	addExpansions(Query query, Set<PhraseMatcher.Phrase> matches, String expandIndex, int maxNumRewrites, boolean removeOriginal, boolean addUnitToRewrites)	Add Expansions to the matching phrases
static Query	addRewritesAsEquiv(Query query, String matchingStr, String rewrites, boolean addUnitToRewrites, int maxNumRewrites)	Add query expansion to the query tree
static Query	addUnitToOriginalQuery(Query query, String boostingQuery, boolean keepOriginalQuery)	Add proximity boosting to original query by modifying the query tree directly
static String	convertMatchToString(PhraseMatcher.Phrase phrase)	Convert Match to String
static Set<PhraseMatcher.Phrase>	getNonOverlappingFullPhraseMatches(PhraseMatcher phraseMatcher, Query query)	Retrieve the longest, from left to right non overlapping full phrase substrings in query based on FSA dictionary
static List<PhraseMatcher.Phrase>	getNonOverlappingMatchesInAndItem(List<PhraseMatcher.Phrase> allMatches, Query query)	Retrieve the longest, from left to right non overlapping substrings in AndItem based on FSA dictionary
static Set<PhraseMatcher.Phrase>	getNonOverlappingPartialPhraseMatches(PhraseMatcher phraseMatcher, Query query)	Retrieve the longest, from left to right non overlapping partial phrase substrings in query based on FSA dictionary

Methods inherited from class java.lang.Object

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

Constructor Details

RewriterFeatures

public RewriterFeatures()

Method Details

addUnitToOriginalQuery

public static Query addUnitToOriginalQuery(Query query,
 String boostingQuery,
 boolean keepOriginalQuery)
                                    throws RuntimeException

Add proximity boosting to original query by modifying the query tree directly

e.g. original Query Tree: (AND aa bb)
if keepOriginalQuery: true
new Query tree: (OR (AND aa bb) "aa bb")
if keepOriginalQuery: false
new Query Tree: "aa bb"

original Query Tree: (OR (AND aa bb) (AND cc dd))
boostingQuery: cc dd
if keepOriginalQuery: true
new Query Tree: (OR (AND aa bb) (AND cc dd) "cc dd")
if keepOriginalQuery: false
new Query Tree: (OR (AND aa bb) "cc dd")

Parameters:

query - Query object from searcher

boostingQuery - query to be boosted

keepOriginalQuery - whether to keep original unboosted query as equiv

Returns:

Modified Query object, return original query object on error

Throws:

RuntimeException

addRewritesAsEquiv

public static Query addRewritesAsEquiv(Query query,
 String matchingStr,
 String rewrites,
 boolean addUnitToRewrites,
 int maxNumRewrites)
                                throws RuntimeException

Add query expansion to the query tree

e.g. origQuery: aa bb
matchingStr: aa bb
rewrite: cc dd, ee ff
if addUnitToRewrites: false
new query tree: (OR (AND aa bb) (AND cc dd) (AND ee ff))
if addUnitToRewrites: true
new query tree: (OR (AND aa bb) "cc dd" "ee ff")

Parameters:

query - Query object from searcher

matchingStr - string used to retrieve the rewrite

rewrites - The rewrite string retrieved from dictionary

addUnitToRewrites - Whether to add unit to rewrites

maxNumRewrites - Max number of rewrites to be added, 0 if no limit

Returns:

Modified Query object, return original query object on error

Throws:

RuntimeException

getNonOverlappingFullPhraseMatches

public static Set<PhraseMatcher.Phrase> getNonOverlappingFullPhraseMatches(PhraseMatcher phraseMatcher,
 Query query)
                                                                    throws RuntimeException

Retrieve the longest, from left to right non overlapping full phrase substrings in query based on FSA dictionary

e.g. query: ((modern AND new AND york AND city AND travel) OR travel) AND ((sunny AND travel AND agency) OR nyc)
dictionary:
mny\tmodern new york
mo\tmodern
modern\tn/a
modern\tnew york\tn/a
new york\tn/a
new york city\tn/a
new york city travel\tn/a
new york company\tn/a
ny\tnew york
nyc\tnew york city\tnew york company
nyct\tnew york city travel
ta\ttravel agency
travel agency\tn/a
return: nyc

Parameters:

phraseMatcher - PhraseMatcher object loaded with FSA dict

query - Query object from the searcher

Returns:

Matching phrases

Throws:

RuntimeException

getNonOverlappingPartialPhraseMatches

public static Set<PhraseMatcher.Phrase> getNonOverlappingPartialPhraseMatches(PhraseMatcher phraseMatcher,
 Query query)
                                                                       throws RuntimeException

Retrieve the longest, from left to right non overlapping partial phrase substrings in query based on FSA dictionary

e.g. query: ((modern AND new AND york AND city AND travel) OR travel) AND ((sunny AND travel AND agency) OR nyc)
dictionary:
mny\tmodern new york
mo\tmodern
modern\tn/a
modern new york\tn/a
new york\tn/a
new york city\tn/a
new york city travel\tn/a
new york company\tn/a
ny\tnew york
nyc\tnew york city\tnew york company
nyct\tnew york city travel
ta\ttravel agency
travel agency\tn/a
return:
modern
new york city travel
travel agency
nyc

Parameters:

phraseMatcher - PhraseMatcher object loaded with FSA dict

query - Query object from the searcher

Returns:

Matching phrases

Throws:

RuntimeException

getNonOverlappingMatchesInAndItem

public static List<PhraseMatcher.Phrase> getNonOverlappingMatchesInAndItem(List<PhraseMatcher.Phrase> allMatches,
 Query query)
                                                                    throws RuntimeException

Retrieve the longest, from left to right non overlapping substrings in AndItem based on FSA dictionary

e.g. subtree: (modern AND new AND york AND city AND travel)
dictionary:
mny\tmodern new york
mo\tmodern
modern\tn/a
modern new york\tn/a
new york\tn/a
new york city\tn/a
new york city travel\tn/a
new york company\tn/a
ny\tnew york
nyc\tnew york city\tnew york company
nyct\tnew york city travel
allMatches:
modern
modern new york
new york
new york city
new york city travel
return:
modern
new york city travel

Parameters:

allMatches - All matches within the subtree

query - Query object from the searcher

Returns:

Matching phrases

Throws:

RuntimeException

addExpansions

public static Query addExpansions(Query query,
 Set<PhraseMatcher.Phrase> matches,
 String expandIndex,
 int maxNumRewrites,
 boolean removeOriginal,
 boolean addUnitToRewrites)
                           throws RuntimeException

Add Expansions to the matching phrases

e.g. Query: nyc travel agency
matching phrase: nyc\tnew york city\tnew york company travel agency\tn/a
if expandIndex is not null and removeOriginal is true
New Query: ((new york city) OR ([expandIndex]:new york city) OR (new york company) OR ([expandIndex]:new york company)) AND ((travel agency) OR ([expandIndex]:travel agency))
if expandIndex is null and removeOriginal is true
New Query: ((new york city) OR (new york company)) AND travel agency
if expandIndex is null and removeOriginal is false
New Query: (nyc OR (new york city) OR (new york company)) AND travel agency

Parameters:

query - Query object from searcher

matches - Set of longest non-overlapping matches

expandIndex - Name of expansion index or null if default index

maxNumRewrites - Max number of rewrites to be added, 0 if no limit

removeOriginal - Whether to remove the original matching phrase

addUnitToRewrites - Whether to add rewrite as phrase

Throws:

RuntimeException

convertMatchToString

public static String convertMatchToString(PhraseMatcher.Phrase phrase)

Convert Match to String

Parameters:

phrase - Match from PhraseMatcher

Returns:

String format of the phrase