Package org.apache.bookkeeper.mledger.util

Class RangeCache<Key extends java.lang.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 java.lang.Comparable<Key>,Value extends io.netty.util.ReferenceCounted>
extends java.lang.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
long	clear()	Remove all the entries from the cache.
org.apache.commons.lang3.tuple.Pair<java.lang.Integer,java.lang.Long>	evictLeastAccessedEntries(long minSize)
long	evictLEntriesBeforeTimestamp(long maxTimestamp)
Value	get(Key key)
protected long	getNumberOfEntries()	Just for testing.
java.util.Collection<Value>	getRange(Key first, Key last)
long	getSize()
boolean	put(Key key, Value value)	Insert.
org.apache.commons.lang3.tuple.Pair<java.lang.Integer,java.lang.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 Detail

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 Detail

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

get

public Value get(Key key)

getRange

public java.util.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<java.lang.Integer,java.lang.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<java.lang.Integer,java.lang.Long> evictLeastAccessedEntries(long minSize)

Parameters:

minSize -

Returns:

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

evictLEntriesBeforeTimestamp

public 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 long clear()

Remove all the entries from the cache.

Returns:

size of removed entries