org.apache.lucene.search.suggest

Class Lookup

java.lang.Object

org.apache.lucene.search.suggest.Lookup

All Implemented Interfaces:

Accountable

Direct Known Subclasses:

AnalyzingInfixSuggester, AnalyzingSuggester, FreeTextSuggester, FSTCompletionLookup, JaspellLookup, TSTLookup, WFSTCompletionLookup

public abstract class Lookup
extends Object
implements Accountable

Simple Lookup interface for CharSequence 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 and Description
static class	Lookup.LookupPriorityQueue A PriorityQueue collecting a fixed size of high priority Lookup.LookupResult
static class	Lookup.LookupResult Result of a lookup.

Field Summary

Fields

Modifier and Type	Field and Description
static Comparator<CharSequence>	CHARSEQUENCE_COMPARATOR A simple char-by-char comparator for CharSequence

Constructor Summary

Constructors

Constructor and Description
Lookup() Sole constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	build(Dictionary dict) Build lookup from a dictionary.
abstract void	build(InputIterator inputIterator) Builds up a new internal Lookup representation based on the given InputIterator.
Collection<Accountable>	getChildResources() Returns nested resources of this class.
abstract long	getCount() Get the number of entries the lookup was built with
abstract boolean	load(DataInput input) Discard current lookup data and load it from a previously saved copy.
boolean	load(InputStream input) Calls load(DataInput) after converting InputStream to DataInput
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, BooleanQuery contextFilerQuery, int num, boolean allTermsRequired, boolean doHighlight) Look up a key and return possible completion for this key.
abstract List<Lookup.LookupResult>	lookup(CharSequence key, Set<BytesRef> contexts, boolean onlyMorePopular, int num) Look up a key and return possible completion for this key.
abstract boolean	store(DataOutput output) Persist the constructed lookup data to a directory.
boolean	store(OutputStream output) Calls store(DataOutput) after converting OutputStream to DataOutput

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

ramBytesUsed

Field Detail

CHARSEQUENCE_COMPARATOR

public static final Comparator<CharSequence> CHARSEQUENCE_COMPARATOR

A simple char-by-char comparator for CharSequence

Constructor Detail

Lookup

public Lookup()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

build

public void build(Dictionary dict)
           throws IOException

Build lookup from a dictionary. Some implementations may require sorted or unsorted keys from the dictionary's iterator - use SortedInputIterator or UnsortedInputIterator in such case.

Throws:

IOException

load

public boolean load(InputStream input)
             throws IOException

Calls load(DataInput) after converting InputStream to DataInput

Throws:

IOException

store

public boolean store(OutputStream output)
              throws IOException

Calls store(DataOutput) after converting OutputStream to DataOutput

Throws:

IOException

getCount

public abstract long getCount()
                       throws IOException

Get the number of entries the lookup was built with

Returns:

total number of suggester entries

Throws:

IOException

build

public abstract void build(InputIterator inputIterator)
                    throws IOException

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

Throws:

IOException

lookup

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

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

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)

Throws:

IOException

lookup

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

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

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,
                               BooleanQuery contextFilerQuery,
                               int num,
                               boolean allTermsRequired,
                               boolean doHighlight)
                                 throws IOException

Look up a key and return possible completion for this key. This needs to be overridden by all implementing classes as the default implementation just returns null

Parameters:

key - the lookup key

contextFilerQuery - A query for further filtering the result of the key lookup

num - maximum number of results to return

allTermsRequired - true is all terms are required

doHighlight - set to true if key should be highlighted

Returns:

a list of suggestions/completions. The default implementation returns null, meaning each @Lookup implementation should override this and provide their own implementation

Throws:

IOException - when IO exception occurs

store

public abstract boolean store(DataOutput output)
                       throws IOException

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

Parameters:

output - DataOutput to write the data to.

Returns:

true if successful, false if unsuccessful or not supported.

Throws:

IOException - when fatal IO error occurs.

load

public abstract boolean load(DataInput input)
                      throws IOException

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

Parameters:

input - the DataInput to load the lookup data.

Returns:

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

Throws:

IOException - when fatal IO error occurs.

getChildResources

public Collection<Accountable> getChildResources()

Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).

Specified by:

getChildResources in interface Accountable

See Also:

Accountables