Package org.apache.bookkeeper.mledger.util

Class RangeCache<Key extends Comparable<Key>,Value extends io.netty.util.ReferenceCounted>

java.lang.Object

org.apache.bookkeeper.mledger.util.RangeCache<Key,Value>

Type Parameters:

Key - Cache key. Needs to be Comparable

Value - Cache value

public class RangeCache<Key extends Comparable<Key>,Value extends io.netty.util.ReferenceCounted>
extends Object

Special type of cache where get() and delete() operations can be done over a range of keys.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	RangeCache.TimestampExtractor<ValueT>	Interface of a object that is able to the extract the "timestamp" of the cached values.
static interface	RangeCache.Weighter<ValueT>	Interface of a object that is able to the extract the "weight" (size/cost/space) of the cached values.

Constructor Summary

Constructors

Constructor	Description
RangeCache()	Construct a new RangeLruCache with default Weighter.
RangeCache(RangeCache.Weighter<Value> weighter, RangeCache.TimestampExtractor<Value> timestampExtractor)	Construct a new RangeLruCache.

Method Summary

Modifier and Type	Method	Description
org.apache.commons.lang3.tuple.Pair<Integer,Long>	clear()	Remove all the entries from the cache.
org.apache.commons.lang3.tuple.Pair<Integer,Long>	evictLeastAccessedEntries(long minSize)
org.apache.commons.lang3.tuple.Pair<Integer,Long>	evictLEntriesBeforeTimestamp(long maxTimestamp)
boolean	exists(Key key)
Value	get(Key key)
protected long	getNumberOfEntries()	Just for testing.
Collection<Value>	getRange(Key first, Key last)
long	getSize()
boolean	put(Key key, Value value)	Insert.
org.apache.commons.lang3.tuple.Pair<Integer,Long>	removeRange(Key first, Key last, boolean lastInclusive)

Methods inherited from class java.lang.Object

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

Constructor Details

RangeCache

public RangeCache()

Construct a new RangeLruCache with default Weighter.

RangeCache

public RangeCache(RangeCache.Weighter<Value> weighter,
 RangeCache.TimestampExtractor<Value> timestampExtractor)

Construct a new RangeLruCache.

Parameters:

weighter - a custom weighter to compute the size of each stored value

Method Details

put

public boolean put(Key key,
 Value value)

Insert.

Parameters:

key -

value - ref counted value with at least 1 ref to pass on the cache

Returns:

whether the entry was inserted in the cache

exists

public boolean exists(Key key)

get

public Value get(Key key)

getRange

public Collection<Value> getRange(Key first,
 Key last)

Parameters:

first - the first key in the range

last - the last key in the range (inclusive)

Returns:

a collections of the value found in cache

removeRange

public org.apache.commons.lang3.tuple.Pair<Integer,Long> removeRange(Key first,
 Key last,
 boolean lastInclusive)

Parameters:

first -

last -

lastInclusive -

Returns:

an pair of ints, containing the number of removed entries and the total size

evictLeastAccessedEntries

public org.apache.commons.lang3.tuple.Pair<Integer,Long> evictLeastAccessedEntries(long minSize)

Parameters:

minSize -

Returns:

a pair containing the number of entries evicted and their total size

evictLEntriesBeforeTimestamp

public org.apache.commons.lang3.tuple.Pair<Integer,Long> evictLEntriesBeforeTimestamp(long maxTimestamp)

Parameters:

maxTimestamp - the max timestamp of the entries to be evicted

Returns:

the tota

getNumberOfEntries

protected long getNumberOfEntries()

Just for testing. Getting the number of entries is very expensive on the conncurrent map

getSize

public long getSize()

clear

public org.apache.commons.lang3.tuple.Pair<Integer,Long> clear()

Remove all the entries from the cache.

Returns:

size of removed entries