org.apache.lucene.search
Class FilterManager

java.lang.Object
  org.apache.lucene.search.FilterManager

public class FilterManager
extends Object

Filter caching singleton. It can be used to save filters locally for reuse. This class makes it possible to cache Filters even when using RMI, as it keeps the cache on the searcher side of the RMI connection. Also could be used as a persistent storage for any filter as long as the filter provides a proper hashCode(), as that is used as the key in the cache. The cache is periodically cleaned up from a separate thread to ensure the cache doesn't exceed the maximum size.

Nested Class Summary

protected class	FilterManager.FilterCleaner Keeps the cache from getting too big.
protected class	FilterManager.FilterItem Holds the filter and the last time the filter was used, to make LRU-based cache cleaning possible.

Field Summary

protected Map	cache The cache itself
protected int	cacheCleanSize Maximum allowed cache size
protected long	cleanSleepTime Cache cleaning frequency
protected static int	DEFAULT_CACHE_CLEAN_SIZE The default maximum number of Filters in the cache
protected static long	DEFAULT_CACHE_SLEEP_TIME The default frequency of cache cleanup
protected FilterManager.FilterCleaner	filterCleaner Cache cleaner that runs in a separate thread
protected static FilterManager	manager

Constructor Summary

protected

FilterManager() Sets up the FilterManager singleton.

Method Summary

Filter	getFilter(Filter filter) Returns the cached version of the filter.
static FilterManager	getInstance()
void	setCacheSize(int cacheCleanSize) Sets the max size that cache should reach before it is cleaned up
void	setCleanThreadSleepTime(long cleanSleepTime) Sets the cache cleaning frequency in milliseconds.

Methods inherited from class java.lang.Object

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

Field Detail

manager

protected static FilterManager manager

DEFAULT_CACHE_CLEAN_SIZE

protected static final int DEFAULT_CACHE_CLEAN_SIZE

The default maximum number of Filters in the cache

See Also:

Constant Field Values

DEFAULT_CACHE_SLEEP_TIME

protected static final long DEFAULT_CACHE_SLEEP_TIME

The default frequency of cache cleanup

See Also:

Constant Field Values

cache

protected Map cache

The cache itself

cacheCleanSize

protected int cacheCleanSize

Maximum allowed cache size

cleanSleepTime

protected long cleanSleepTime

Cache cleaning frequency

filterCleaner

protected FilterManager.FilterCleaner filterCleaner

Cache cleaner that runs in a separate thread

Constructor Detail

FilterManager

protected FilterManager()

Sets up the FilterManager singleton.

Method Detail

getInstance

public static FilterManager getInstance()

setCacheSize

public void setCacheSize(int cacheCleanSize)

Sets the max size that cache should reach before it is cleaned up

Parameters:

cacheCleanSize - maximum allowed cache size

setCleanThreadSleepTime

public void setCleanThreadSleepTime(long cleanSleepTime)

Sets the cache cleaning frequency in milliseconds.

Parameters:

cleanSleepTime - cleaning frequency in milliseconds

getFilter

public Filter getFilter(Filter filter)

Returns the cached version of the filter. Allows the caller to pass up a small filter but this will keep a persistent version around and allow the caching filter to do its job.

Parameters:

filter - The input filter

Returns:

The cached version of the filter