java.lang.Object
- org.apache.lucene.search.suggest.Lookup

Direct Known Subclasses:

FSTCompletionLookup, FSTLookup, JaspellLookup, TSTLookup, WFSTCompletionLookup
```
public abstract class Lookup
extends Object
```
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	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 Description

static Comparator<CharSequence> CHARSEQUENCE_COMPARATOR
A simple char-by-char comparator for CharSequence

Constructor Summary

Constructors
Constructor Description

Lookup()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`build(Dictionary dict)`	Build lookup from a dictionary.
`abstract void`	`build(TermFreqIterator tfit)`	Builds up a new internal `Lookup` representation based on the given `TermFreqIterator`.
`abstract boolean`	`load(InputStream input)`	Discard current lookup data and load it from a previously saved copy.
`abstract List<Lookup.LookupResult>`	`lookup(CharSequence key, boolean onlyMorePopular, int num)`	Look up a key and return possible completion for this key.
`abstract boolean`	`store(OutputStream output)`	Persist the constructed lookup data to a directory.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - CHARSEQUENCE_COMPARATOR
```
public static final Comparator<CharSequence> CHARSEQUENCE_COMPARATOR
```
    A simple char-by-char comparator for CharSequence
- Constructor Detail
  - Lookup
```
public Lookup()
```
- 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 SortedTermFreqIteratorWrapper or UnsortedTermFreqIteratorWrapper in such case.
    
    Throws:
    
    IOException
  - build
```
public abstract void build(TermFreqIterator tfit)
                    throws IOException
```
    Builds up a new internal Lookup representation based on the given TermFreqIterator. The implementation might re-sort the data internally.
    
    Throws:
    
    IOException
  - lookup
```
public abstract List<Lookup.LookupResult> lookup(CharSequence key,
                                                 boolean onlyMorePopular,
                                                 int num)
```
    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)
  - store
```
public abstract boolean store(OutputStream output)
                       throws IOException
```
    Persist the constructed lookup data to a directory. Optional operation.
    
    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 abstract boolean load(InputStream input)
                      throws IOException
```
    Discard current lookup data and load it from a previously saved copy. Optional operation.
    
    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.

Class Lookup

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CHARSEQUENCE_COMPARATOR

Constructor Detail

Lookup

Method Detail

build

build

lookup

store

load