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

java.lang.Object
  org.apache.lucene.search.suggest.Lookup
      org.apache.lucene.search.suggest.analyzing.AnalyzingInfixSuggester

All Implemented Interfaces:

Closeable

public class AnalyzingInfixSuggester
extends Lookup
implements Closeable

Analyzes the input text and then suggests matches based on prefix matches to any tokens in the indexed text. This also highlights the tokens that match.

This just uses an ordinary Lucene index. It supports payloads, and records these as a BinaryDocValues field. Matches are sorted only by the suggest weight; it would be nice to support blended score + weight sort in the future. This means this suggester best applies when there is a strong apriori ranking of all the suggestions.

Nested Class Summary

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

Lookup.LookupPriorityQueue, Lookup.LookupResult

Field Summary

static int	DEFAULT_MIN_PREFIX_CHARS Default minimum number of leading characters before PrefixQuery is used (4).
protected IndexSearcher	searcher IndexSearcher used for lookups.
protected static String	TEXT_FIELD_NAME Field name used for the indexed text.

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

CHARSEQUENCE_COMPARATOR

Constructor Summary

AnalyzingInfixSuggester(Version matchVersion, File indexPath, Analyzer analyzer)
Create a new instance, loading from a previously built directory, if it exists.

AnalyzingInfixSuggester(Version matchVersion, File indexPath, Analyzer indexAnalyzer, Analyzer queryAnalyzer, int minPrefixChars)
Create a new instance, loading from a previously built directory, if it exists.

Method Summary

protected void	addPrefixMatch(StringBuilder sb, String surface, String analyzed, String prefixToken) Append a matched prefix token, to the provided StringBuilder.
protected void	addWholeMatch(StringBuilder sb, String surface, String analyzed) Appends the whole matched token to the provided StringBuilder.
void	build(TermFreqIterator iter) Builds up a new internal Lookup representation based on the given TermFreqIterator.
void	close()
protected Query	finishQuery(BooleanQuery in, boolean allTermsRequired) Subclass can override this to tweak the Query before searching.
protected Directory	getDirectory(File path) Subclass can override to choose a specific Directory implementation.
protected IndexWriterConfig	getIndexWriterConfig(Version matchVersion, Analyzer indexAnalyzer) Override this to customize index settings, e.g.
protected Query	getLastTokenQuery(String token) This is called if the last token isn't ended (e.g.
boolean	load(InputStream out) Discard current lookup data and load it from a previously saved copy.
List<Lookup.LookupResult>	lookup(CharSequence key, boolean onlyMorePopular, int num) Look up a key and return possible completion for this key.
List<Lookup.LookupResult>	lookup(CharSequence key, int num, boolean allTermsRequired, boolean doHighlight) Retrieve suggestions, specifying whether all terms must match (allTermsRequired) and whether the hits should be highlighted (doHighlight).
boolean	store(OutputStream out) Persist the constructed lookup data to a directory.

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

build

Methods inherited from class java.lang.Object

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

Field Detail

TEXT_FIELD_NAME

protected static final String TEXT_FIELD_NAME

Field name used for the indexed text.

See Also:

Constant Field Values

searcher

protected IndexSearcher searcher

IndexSearcher used for lookups.

DEFAULT_MIN_PREFIX_CHARS

public static final int DEFAULT_MIN_PREFIX_CHARS

Default minimum number of leading characters before PrefixQuery is used (4).

See Also:

Constant Field Values

Constructor Detail

AnalyzingInfixSuggester

public AnalyzingInfixSuggester(Version matchVersion,
                               File indexPath,
                               Analyzer analyzer)
                        throws IOException

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

Throws:

IOException

AnalyzingInfixSuggester

public AnalyzingInfixSuggester(Version matchVersion,
                               File indexPath,
                               Analyzer indexAnalyzer,
                               Analyzer queryAnalyzer,
                               int minPrefixChars)
                        throws IOException

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

Parameters:

minPrefixChars - Minimum number of leading characters before PrefixQuery is used (default 4). Prefixes shorter than this are indexed as character ngrams (increasing index size but making lookups faster).

Throws:

IOException

Method Detail

getIndexWriterConfig

protected IndexWriterConfig getIndexWriterConfig(Version matchVersion,
                                                 Analyzer indexAnalyzer)

Override this to customize index settings, e.g. which codec to use.

getDirectory

protected Directory getDirectory(File path)
                          throws IOException

Subclass can override to choose a specific Directory implementation.

Throws:

IOException

build

public void build(TermFreqIterator iter)
           throws IOException

Description copied from class: Lookup

Builds up a new internal Lookup representation based on the given TermFreqIterator. The implementation might re-sort the data internally.

Specified by:

build in class Lookup

Throws:

IOException

lookup

public List<Lookup.LookupResult> lookup(CharSequence key,
                                        boolean onlyMorePopular,
                                        int num)

Description copied from class: Lookup

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

Specified by:

lookup in class Lookup

Parameters:

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

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)

getLastTokenQuery

protected Query getLastTokenQuery(String token)
                           throws IOException

This is called if the last token isn't ended (e.g. user did not type a space after it). Return an appropriate Query clause to add to the BooleanQuery.

Throws:

IOException

lookup

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

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

finishQuery

protected Query finishQuery(BooleanQuery in,
                            boolean allTermsRequired)

Subclass can override this to tweak the Query before searching.

addWholeMatch

protected void addWholeMatch(StringBuilder sb,
                             String surface,
                             String analyzed)

Appends the whole matched token to the provided StringBuilder.

addPrefixMatch

protected void addPrefixMatch(StringBuilder sb,
                              String surface,
                              String analyzed,
                              String prefixToken)

Append a matched prefix token, to the provided StringBuilder.

Parameters:

sb - StringBuilder to append to

surface - The fragment of the surface form (indexed during build(org.apache.lucene.search.spell.TermFreqIterator), corresponding to this match

analyzed - The analyzed token that matched

prefixToken - The prefix of the token that matched

store

public boolean store(OutputStream out)

Description copied from class: Lookup

Persist the constructed lookup data to a directory. Optional operation.

Specified by:

store in class Lookup

Parameters:

out - OutputStream to write the data to.

Returns:

true if successful, false if unsuccessful or not supported.

load

public boolean load(InputStream out)

Description copied from class: Lookup

Discard current lookup data and load it from a previously saved copy. Optional operation.

Specified by:

load in class Lookup

Parameters:

out - the InputStream to load the lookup data.

Returns:

true if completed successfully, false if unsuccessful or not supported.

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Throws:

IOException