com.yahoo.search.query.rewrite.rewriters

Class GenericExpansionRewriter

java.lang.Object

com.yahoo.component.AbstractComponent

com.yahoo.component.chain.ChainedComponent

com.yahoo.processing.Processor

com.yahoo.search.Searcher

com.yahoo.search.query.rewrite.QueryRewriteSearcher

com.yahoo.search.query.rewrite.rewriters.GenericExpansionRewriter

All Implemented Interfaces:

com.yahoo.component.Component, Comparable<com.yahoo.component.Component>

public class GenericExpansionRewriter
extends QueryRewriteSearcher

This rewriter would add rewrites to entities (e.g abbreviation, synonym, etc)
to boost precision - FSA dict: [normalized original query]\t[rewrite 1]\t[rewrite 2]\t[etc]
- Features:
RewritesAsUnitEquiv flag: add proximity boosted rewrites
PartialPhraseMatch flag: whether to match whole phrase or partial phrase
MaxRewrites flag: the maximum number of rewrites to be added

Author:

Karen Sze Wing Lee

Field Summary

Fields

Modifier and Type	Field and Description
static String	GENERIC_EXPAND_DICT
static String	GENERIC_EXPAND_DICT_FILENAME
private Logger	logger
private PhraseMatcher	phraseMatcher
static String	REWRITER_NAME
private boolean	SKIP_REWRITER_IF_REWRITTEN

Fields inherited from class com.yahoo.search.query.rewrite.QueryRewriteSearcher

rewriterDicts

Fields inherited from class com.yahoo.component.AbstractComponent

isDeconstructable

Constructor Summary

Constructors

Constructor and Description
GenericExpansionRewriter(com.yahoo.component.ComponentId id, com.yahoo.filedistribution.fileacquirer.FileAcquirer fileAcquirer, RewritesConfig config) Constructor for GenericExpansionRewriter.
GenericExpansionRewriter(RewritesConfig config, HashMap<String,File> fileList) Constructor for GenericExpansionRewriter unit test.

Method Summary

Modifier and Type	Method and Description
boolean	configure(com.yahoo.filedistribution.fileacquirer.FileAcquirer fileAcquirer, RewritesConfig config, HashMap<String,File> fileList) Instance creation time config loading besides FSA.
HashMap<String,String>	getDefaultFSAs() Get default FSA dictionary names
String	getRewriterName() Get the name of the rewriter
boolean	getSkipRewriterIfRewritten() Get the flag which specifies whether this rewriter should be skipped if the query has been rewritten
HashMap<String,Object>	rewrite(Query query, String dictKey) Main logic of rewriter - Retrieve rewrites from FSA dict - rewrite query using features that are enabled by user

Methods inherited from class com.yahoo.search.query.rewrite.QueryRewriteSearcher

getQPConfig, getRewriteFromFSA, search

Methods inherited from class com.yahoo.search.Searcher

ensureFilled, fill, getLogger, process, toString

Methods inherited from class com.yahoo.component.chain.ChainedComponent

getAnnotatedDependencies, getDefaultAnnotatedDependencies, getDependencies, initDependencies

Methods inherited from class com.yahoo.component.AbstractComponent

clone, compareTo, deconstruct, getClassName, getId, getIdString, hasInitializedId, initId, isDeconstructable, setIsDeconstructable

Methods inherited from class java.lang.Object

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

Field Detail

SKIP_REWRITER_IF_REWRITTEN

private final boolean SKIP_REWRITER_IF_REWRITTEN

See Also:

Constant Field Values

REWRITER_NAME

public static final String REWRITER_NAME

See Also:

Constant Field Values

GENERIC_EXPAND_DICT

public static final String GENERIC_EXPAND_DICT

See Also:

Constant Field Values

GENERIC_EXPAND_DICT_FILENAME

public static final String GENERIC_EXPAND_DICT_FILENAME

See Also:

Constant Field Values

phraseMatcher

private PhraseMatcher phraseMatcher

logger

private Logger logger

Constructor Detail

GenericExpansionRewriter

@Inject
public GenericExpansionRewriter(com.yahoo.component.ComponentId id,
                                        com.yahoo.filedistribution.fileacquirer.FileAcquirer fileAcquirer,
                                        RewritesConfig config)

Constructor for GenericExpansionRewriter. Load configs using default format

GenericExpansionRewriter

public GenericExpansionRewriter(RewritesConfig config,
                                HashMap<String,File> fileList)

Constructor for GenericExpansionRewriter unit test. Load configs using default format

Method Detail

configure

public boolean configure(com.yahoo.filedistribution.fileacquirer.FileAcquirer fileAcquirer,
                         RewritesConfig config,
                         HashMap<String,File> fileList)

Instance creation time config loading besides FSA. Create PhraseMatcher from FSA dict

Specified by:

configure in class QueryRewriteSearcher

Parameters:

fileAcquirer - Required param for retrieving file type config (see vespa's search container doc for more detail)

config - Config from vespa-services.xml (see vespa's search container doc for more detail)

fileList - pairs of file name and file handler for unit tests

Returns:

boolean true if loaded successfully, false otherwise

rewrite

public HashMap<String,Object> rewrite(Query query,
                                      String dictKey)
                               throws RuntimeException

Main logic of rewriter
- Retrieve rewrites from FSA dict
- rewrite query using features that are enabled by user

Specified by:

rewrite in class QueryRewriteSearcher

Parameters:

query - Query object from searcher

dictKey - the key passed from previous rewriter to be treated as "original query from user" For example, if previous is misspell rewriter, it would pass the corrected query as the "original query from user". For other rewriters which add variants, abbr, etc to the query, the original query should be passed as a key. This rewriter could still choose to ignore this key. This key is not the rewritten query itself. For example, if original query is (willl smith) and the rewritten query is (willl smith) OR (will smith) the key to be passed could be (will smith)

Returns:

HashMap which contains the key value pairs:
- whether this query has been rewritten by this rewriter
key: rewritten
value: true or false
- the key to be treated as "original query from user" in next rewriter downstream, for example, misspell rewriter would pass the corrected query as the "original query from user" to the next rewriter. For other rewriters which add variants, abbr, etc to the query, the original query should be passed as a key. This key is not necessarily consumed by the next rewriter. The next rewriter can still choose to ignore this key.
key: newDictKey
value: new dict key

Throws:

RuntimeException

getSkipRewriterIfRewritten

public boolean getSkipRewriterIfRewritten()

Get the flag which specifies whether this rewriter should be skipped if the query has been rewritten

Specified by:

getSkipRewriterIfRewritten in class QueryRewriteSearcher

Returns:

true if rewriter should be skipped, false otherwise

getRewriterName

public String getRewriterName()

Get the name of the rewriter

Specified by:

getRewriterName in class QueryRewriteSearcher

Returns:

Name of the rewriter

getDefaultFSAs

public HashMap<String,String> getDefaultFSAs()

Get default FSA dictionary names

Specified by:

getDefaultFSAs in class QueryRewriteSearcher

Returns:

Pair of FSA dictionary name and filename