org.apache.lucene.search.suggest.tst
Class TSTLookup

java.lang.Object
  org.apache.lucene.search.suggest.Lookup
      org.apache.lucene.search.suggest.tst.TSTLookup

public class TSTLookup
extends Lookup

Suggest implementation based on a Ternary Search Tree

See Also:

TSTAutocomplete

Nested Class Summary

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

Lookup.LookupPriorityQueue, Lookup.LookupResult

Field Summary

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

CHARSEQUENCE_COMPARATOR

Constructor Summary

TSTLookup()
Creates a new TSTLookup with an empty Ternary Search Tree.

Method Summary

boolean	add(CharSequence key, Object value) Adds a new node if key already exists, otherwise replaces its value.
void	build(TermFreqIterator tfit) Builds up a new internal Lookup representation based on the given TermFreqIterator.
Object	get(CharSequence key) Returns the value for the specified key, or null if the key does not exist.
boolean	load(InputStream input) 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.
boolean	store(OutputStream output) 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

Constructor Detail

TSTLookup

public TSTLookup()

Creates a new TSTLookup with an empty Ternary Search Tree.

See Also:

build(TermFreqIterator)

Method Detail

build

public void build(TermFreqIterator tfit)
           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

add

public boolean add(CharSequence key,
                   Object value)

Adds a new node if key already exists, otherwise replaces its value.

This method always returns true.

get

public Object get(CharSequence key)

Returns the value for the specified key, or null if the key does not exist.

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)

store

public boolean store(OutputStream output)
              throws IOException

Description copied from class: Lookup

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

Specified by:

store in class Lookup

Parameters:

output - OutputStream to write the data to.

Returns:

true if successful, false if unsuccessful or not supported.

Throws:

IOException - when fatal IO error occurs.

load

public boolean load(InputStream input)
             throws IOException

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:

input - the InputStream to load the lookup data.

Returns:

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

Throws:

IOException - when fatal IO error occurs.