Module org.apache.lucene.facet

Package org.apache.lucene.facet.taxonomy.writercache

Class NameIntCacheLRU

java.lang.Object

org.apache.lucene.facet.taxonomy.writercache.NameIntCacheLRU

Direct Known Subclasses:

NameHashIntCacheLRU

class NameIntCacheLRU
extends Object

An LRU cache of mapping from name to int. Used to cache Ordinals of category paths.

Field Summary

Fields

Modifier and Type	Field	Description
private HashMap<Object,Integer>	cache
private int	maxCacheSize
(package private) long	nHits
(package private) long	nMisses

Constructor Summary

Constructors

Constructor	Description
NameIntCacheLRU(int maxCacheSize)

Method Summary

Modifier and Type	Method	Description
(package private) void	clear()
private void	createCache(int maxSize)
(package private) Integer	get(FacetLabel name)
int	getMaxSize()	Maximum number of cache entries before eviction.
int	getSize()	Number of entries currently in the cache.
private boolean	isCacheFull()
(package private) Object	key(FacetLabel name)	Subclasses can override this to provide caching by e.g.
(package private) Object	key(FacetLabel name, int prefixLen)
(package private) boolean	makeRoomLRU()	If cache is full remove least recently used entries from cache.
(package private) boolean	put(FacetLabel name, int prefixLen, Integer val)
(package private) boolean	put(FacetLabel name, Integer val)	Add a new value to cache.
(package private) String	stats()

Methods inherited from class java.lang.Object

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

Field Details

cache

private HashMap<Object,Integer> cache

nMisses

long nMisses

nHits

long nHits

maxCacheSize

private int maxCacheSize

Constructor Details

NameIntCacheLRU

NameIntCacheLRU(int maxCacheSize)

Method Details

getMaxSize

public int getMaxSize()

Maximum number of cache entries before eviction.

getSize

public int getSize()

Number of entries currently in the cache.

createCache

private void createCache(int maxSize)

get

Integer get(FacetLabel name)

key

Object key(FacetLabel name)

Subclasses can override this to provide caching by e.g. hash of the string.

key

Object key(FacetLabel name,
 int prefixLen)

put

boolean put(FacetLabel name,
 Integer val)

Add a new value to cache. Return true if cache became full and some room need to be made.

put

boolean put(FacetLabel name,
 int prefixLen,
 Integer val)

isCacheFull

private boolean isCacheFull()

clear

void clear()

stats

String stats()

makeRoomLRU

boolean makeRoomLRU()

If cache is full remove least recently used entries from cache. Return true if anything was removed, false otherwise.

See comment in DirectoryTaxonomyWriter.addToCache(CategoryPath, int) for an explanation why we clean 1/3rd of the cache, and not just one entry.