Package org.postgresql.util

Class LruCache<Key,Value extends CanEstimateSize>

java.lang.Object

org.postgresql.util.LruCache<Key,Value>

public class LruCache<Key,Value extends CanEstimateSize>
extends java.lang.Object

Caches values in simple least-recently-accessed order.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	LruCache.CreateAction<Key,Value>	When the entry is not present in cache, this create action is used to create one.
static interface	LruCache.EvictAction<Value>	Action that is invoked when the entry is removed from the cache.

Field Summary

Fields

Modifier and Type	Field	Description
static LruCache.CreateAction	NOOP_CREATE_ACTION
static LruCache.EvictAction	NOOP_EVICT_ACTION

Constructor Summary

Constructors

Constructor	Description
LruCache(int maxSizeEntries, long maxSizeBytes, boolean accessOrder)
LruCache(int maxSizeEntries, long maxSizeBytes, boolean accessOrder, LruCache.CreateAction<Key,Value> createAction, LruCache.EvictAction<Value> onEvict)

Method Summary

Modifier and Type	Method	Description
Value	borrow(Key key)	Borrows an entry from the cache.
Value	get(Key key)	Returns an entry from the cache.
void	put(Key key, Value value)	Returns given value to the cache

Methods inherited from class java.lang.Object

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

Field Detail

NOOP_CREATE_ACTION

public static final LruCache.CreateAction NOOP_CREATE_ACTION

NOOP_EVICT_ACTION

public static final LruCache.EvictAction NOOP_EVICT_ACTION

Constructor Detail

LruCache

public LruCache(int maxSizeEntries,
                long maxSizeBytes,
                boolean accessOrder)

LruCache

public LruCache(int maxSizeEntries,
                long maxSizeBytes,
                boolean accessOrder,
                LruCache.CreateAction<Key,Value> createAction,
                LruCache.EvictAction<Value> onEvict)

Method Detail

get

public Value get(Key key)

Returns an entry from the cache.

Parameters:

key - cache key

Returns:

entry from cache or null if cache does not contain given key.

borrow

public Value borrow(Key key)
             throws java.sql.SQLException

Borrows an entry from the cache.

Parameters:

key - cache key

Returns:

entry from cache or newly created entry if cache does not contain given key.

Throws:

java.sql.SQLException - if entry creation fails

put

public void put(Key key,
                Value value)

Returns given value to the cache

Parameters:

key - key

value - value