Class Int2ObjectCache<V>
- java.lang.Object
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- org.agrona.collections.Int2ObjectCache<V>
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- Type Parameters:
V
- type of values stored in theMap
- All Implemented Interfaces:
java.util.Map<java.lang.Integer,V>
public class Int2ObjectCache<V> extends java.lang.Object implements java.util.Map<java.lang.Integer,V>
A cache implementation specialised for int keys using open addressing to probe a set of fixed size.The eviction strategy is to remove the oldest in a set if the key is not found, or if found then that item. The newly inserted item becomes the youngest in the set. Sets are evicted on a first in, first out, manner unless replacing a matching key.
A good set size would be in the range of 2 to 16 so that the references/keys can fit in a cache-line (assuming references are 32-bit references and 64-byte cache lines, YMMV). A linear search within a cache line is much less costly than a cache-miss to another line.
Null values are not supported by this cache.
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Nested Class Summary
Nested Classes Modifier and Type Class Description (package private) class
Int2ObjectCache.AbstractIterator<T>
Base iterator implementation that contains basic logic of traversing the element in the backing array.class
Int2ObjectCache.EntryIterator
Iterator over entries which supports access to unboxed keys viaInt2ObjectCache.EntryIterator.getIntKey()
.class
Int2ObjectCache.EntrySet
Set of entries which supports cached iterator to avoid allocation.class
Int2ObjectCache.KeyIterator
Iterator over keys which supports access to unboxed keys viaInt2ObjectCache.KeyIterator.nextInt()
.class
Int2ObjectCache.KeySet
A key set implementation which supports cached iterator to avoid allocation.class
Int2ObjectCache.ValueCollection
Collection of values which supports cached iterator to avoid allocation.class
Int2ObjectCache.ValueIterator
An iterator over values.
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Field Summary
Fields Modifier and Type Field Description private long
cacheHits
private long
cacheMisses
private long
cachePuts
private int
capacity
private Int2ObjectCache.EntrySet
entrySet
private java.util.function.Consumer<V>
evictionConsumer
private int[]
keys
private Int2ObjectCache.KeySet
keySet
private int
mask
private int
setSize
private int
setSizeShift
private int
size
private Int2ObjectCache.ValueCollection
valueCollection
private java.lang.Object[]
values
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Constructor Summary
Constructors Constructor Description Int2ObjectCache(int numSets, int setSize, java.util.function.Consumer<V> evictionConsumer)
Constructs cache with provided configuration.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description long
cacheHits()
The number of times a cache hit has occurred on theget(int)
method.long
cacheMisses()
The number of times a cache miss has occurred on theget(int)
method.long
cachePuts()
The number of items that have been put in the cache.int
capacity()
Get the total capacity for the map to which the load factor will be a fraction of.void
clear()
Clear down all items in the cache.V
compute(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
Attempts to compute a mapping for the specified key and its current mapped value (ornull
if there is no current mapping).V
compute(java.lang.Integer key, java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> remappingFunction)
V
computeIfAbsent(int key, java.util.function.IntFunction<? extends V> mappingFunction)
Get a value for a given key, or if it does ot exist then default the value via aIntFunction
and put it in the cache.V
computeIfAbsent(java.lang.Integer key, java.util.function.Function<? super java.lang.Integer,? extends V> mappingFunction)
V
computeIfPresent(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
If the value for the specified key is present attempts to compute a new mapping given the key and its current mapped value.V
computeIfPresent(java.lang.Integer key, java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> remappingFunction)
boolean
containsKey(int key)
Overloaded version ofMap.containsKey(Object)
that takes a primitive int key.boolean
containsKey(java.lang.Object key)
boolean
containsValue(java.lang.Object value)
Int2ObjectCache.EntrySet
entrySet()
boolean
equals(java.lang.Object o)
void
forEach(java.util.function.BiConsumer<? super java.lang.Integer,? super V> action)
void
forEachInt(IntObjConsumer<? super V> consumer)
Implementation of theforEach(BiConsumer)
that avoids boxing of keys.V
get(int key)
Overloaded version ofMap.get(Object)
that takes a primitive int key.V
get(java.lang.Object key)
V
getOrDefault(int key, V defaultValue)
Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.int
hashCode()
boolean
isEmpty()
Int2ObjectCache.KeySet
keySet()
V
merge(int key, V value, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value.V
merge(java.lang.Integer key, V value, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
V
put(int key, V value)
Overloaded version ofMap.put(Object, Object)
that takes a primitive int key.V
put(java.lang.Integer key, V value)
void
putAll(java.util.Map<? extends java.lang.Integer,? extends V> map)
void
putAll(Int2ObjectCache<? extends V> map)
Put all values from the given map into this one without allocation.V
putIfAbsent(int key, V value)
If the specified key is not already associated with a value (or is mapped tonull
) associates it with the given value and returnsnull
, else returns the current value.V
putIfAbsent(java.lang.Integer key, V value)
V
remove(int key)
Overloaded version ofMap.remove(Object)
that takes a primitive int key.boolean
remove(int key, V value)
Removes the entry for the specified key only if it is currently mapped to the specified value.V
remove(java.lang.Object key)
boolean
remove(java.lang.Object key, java.lang.Object value)
V
replace(int key, V value)
Replaces the entry for the specified key only if it is currently mapped to some value.boolean
replace(int key, V oldValue, V newValue)
Replaces the entry for the specified key only if currently mapped to the specified value.V
replace(java.lang.Integer key, V value)
boolean
replace(java.lang.Integer key, V oldValue, V newValue)
void
replaceAll(java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> function)
void
replaceAllInt(IntObjectToObjectFunction<? super V,? extends V> function)
Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.void
resetCounters()
Reset the cache statistics counters to zero.private void
shuffleDown(int setBeginIndex)
private void
shuffleUp(int fromIndex, int toIndex)
int
size()
java.lang.String
toString()
Int2ObjectCache.ValueCollection
values()
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Field Detail
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cachePuts
private long cachePuts
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cacheHits
private long cacheHits
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cacheMisses
private long cacheMisses
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size
private int size
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capacity
private final int capacity
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setSize
private final int setSize
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setSizeShift
private final int setSizeShift
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mask
private final int mask
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keys
private final int[] keys
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values
private final java.lang.Object[] values
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evictionConsumer
private final java.util.function.Consumer<V> evictionConsumer
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valueCollection
private Int2ObjectCache.ValueCollection valueCollection
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keySet
private Int2ObjectCache.KeySet keySet
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entrySet
private Int2ObjectCache.EntrySet entrySet
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Constructor Detail
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Int2ObjectCache
public Int2ObjectCache(int numSets, int setSize, java.util.function.Consumer<V> evictionConsumer)
Constructs cache with provided configuration.- Parameters:
numSets
- number of sets, must be power or two.setSize
- size of a single set, must be power or two.evictionConsumer
- consumer to be notified when entry is being evicted from the cache.
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Method Detail
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cacheHits
public long cacheHits()
The number of times a cache hit has occurred on theget(int)
method.- Returns:
- the number of times a cache hit has occurred on the
get(int)
method.
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cacheMisses
public long cacheMisses()
The number of times a cache miss has occurred on theget(int)
method.- Returns:
- the number of times a cache miss has occurred on the
get(int)
method.
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cachePuts
public long cachePuts()
The number of items that have been put in the cache.- Returns:
- number of items that have been put in the cache.
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resetCounters
public void resetCounters()
Reset the cache statistics counters to zero.
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capacity
public int capacity()
Get the total capacity for the map to which the load factor will be a fraction of.- Returns:
- the total capacity for the map.
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size
public int size()
- Specified by:
size
in interfacejava.util.Map<java.lang.Integer,V>
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isEmpty
public boolean isEmpty()
- Specified by:
isEmpty
in interfacejava.util.Map<java.lang.Integer,V>
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containsKey
public boolean containsKey(java.lang.Object key)
- Specified by:
containsKey
in interfacejava.util.Map<java.lang.Integer,V>
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containsKey
public boolean containsKey(int key)
Overloaded version ofMap.containsKey(Object)
that takes a primitive int key.- Parameters:
key
- for indexing theMap
- Returns:
- true if the key is found otherwise false.
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containsValue
public boolean containsValue(java.lang.Object value)
- Specified by:
containsValue
in interfacejava.util.Map<java.lang.Integer,V>
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get
public V get(java.lang.Object key)
- Specified by:
get
in interfacejava.util.Map<java.lang.Integer,V>
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get
public V get(int key)
Overloaded version ofMap.get(Object)
that takes a primitive int key.- Parameters:
key
- for indexing theMap
- Returns:
- the value if found otherwise null
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getOrDefault
public V getOrDefault(int key, V defaultValue)
Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.- Parameters:
key
- whose associated value is to be returned.defaultValue
- the default mapping of the key.- Returns:
- the value to which the specified key is mapped, or
defaultValue
if this map contains no mapping for the key.
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forEach
public void forEach(java.util.function.BiConsumer<? super java.lang.Integer,? super V> action)
- Specified by:
forEach
in interfacejava.util.Map<java.lang.Integer,V>
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forEachInt
public void forEachInt(IntObjConsumer<? super V> consumer)
Implementation of theforEach(BiConsumer)
that avoids boxing of keys.- Parameters:
consumer
- to be called for each key/value pair.
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computeIfAbsent
public V computeIfAbsent(java.lang.Integer key, java.util.function.Function<? super java.lang.Integer,? extends V> mappingFunction)
- Specified by:
computeIfAbsent
in interfacejava.util.Map<java.lang.Integer,V>
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computeIfAbsent
public V computeIfAbsent(int key, java.util.function.IntFunction<? extends V> mappingFunction)
Get a value for a given key, or if it does ot exist then default the value via aIntFunction
and put it in the cache.Primitive specialized version of
Map.computeIfAbsent(K, java.util.function.Function<? super K, ? extends V>)
.- Parameters:
key
- to search on.mappingFunction
- to provide a value if the get returns null.- Returns:
- the value if found otherwise the default.
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computeIfPresent
public V computeIfPresent(java.lang.Integer key, java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> remappingFunction)
- Specified by:
computeIfPresent
in interfacejava.util.Map<java.lang.Integer,V>
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computeIfPresent
public V computeIfPresent(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
If the value for the specified key is present attempts to compute a new mapping given the key and its current mapped value.Primitive specialized version of
Map.computeIfPresent(Object, BiFunction)
.- Parameters:
key
- with which the specified value is to be associated.remappingFunction
- the function to compute a value.- Returns:
- the new value associated with the specified key, or null if none.
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compute
public V compute(java.lang.Integer key, java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> remappingFunction)
- Specified by:
compute
in interfacejava.util.Map<java.lang.Integer,V>
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compute
public V compute(int key, IntObjectToObjectFunction<? super V,? extends V> remappingFunction)
Attempts to compute a mapping for the specified key and its current mapped value (ornull
if there is no current mapping).Primitive specialized version of
Map.compute(Object, BiFunction)
.- Parameters:
key
- with which the specified value is to be associated.remappingFunction
- the function to compute a value.- Returns:
- the new value associated with the specified key, or null if none.
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merge
public V merge(java.lang.Integer key, V value, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
- Specified by:
merge
in interfacejava.util.Map<java.lang.Integer,V>
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merge
public V merge(int key, V value, java.util.function.BiFunction<? super V,? super V,? extends V> remappingFunction)
If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result isnull
.Primitive specialized version of
Map.merge(Object, Object, BiFunction)
.- Parameters:
key
- with which the resulting value is to be associated.value
- the non-null value to be merged with the existing value associated with the key or, if no existing value or a null value is associated with the key, to be associated with the key.remappingFunction
- the function to recompute a value if present.- Returns:
- the new value associated with the specified key, or null if no value is associated with the key.
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putIfAbsent
public V putIfAbsent(java.lang.Integer key, V value)
- Specified by:
putIfAbsent
in interfacejava.util.Map<java.lang.Integer,V>
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putIfAbsent
public V putIfAbsent(int key, V value)
If the specified key is not already associated with a value (or is mapped tonull
) associates it with the given value and returnsnull
, else returns the current value.Primitive specialized version of
Map.putIfAbsent(Object, Object)
.- Parameters:
key
- with which the specified value is to be associated.value
- to be associated with the specified key.- Returns:
- the previous value associated with the specified key, or
null
if there was no mapping for the key.
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put
public V put(java.lang.Integer key, V value)
- Specified by:
put
in interfacejava.util.Map<java.lang.Integer,V>
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put
public V put(int key, V value)
Overloaded version ofMap.put(Object, Object)
that takes a primitive int key.- Parameters:
key
- for indexing theMap
value
- to be inserted in theMap
- Returns:
- always null (as per JCache API, as opposed to
Map
)
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remove
public boolean remove(java.lang.Object key, java.lang.Object value)
- Specified by:
remove
in interfacejava.util.Map<java.lang.Integer,V>
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remove
public boolean remove(int key, V value)
Removes the entry for the specified key only if it is currently mapped to the specified value.Primitive specialized version of
Map.remove(Object, Object)
.- Parameters:
key
- key with which the specified value is associated.value
- expected to be associated with the specified key.- Returns:
true
if the value was removed.
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remove
public V remove(java.lang.Object key)
- Specified by:
remove
in interfacejava.util.Map<java.lang.Integer,V>
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remove
public V remove(int key)
Overloaded version ofMap.remove(Object)
that takes a primitive int key.- Parameters:
key
- for indexing theMap
- Returns:
- the value if found otherwise null
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replace
public boolean replace(java.lang.Integer key, V oldValue, V newValue)
- Specified by:
replace
in interfacejava.util.Map<java.lang.Integer,V>
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replace
public boolean replace(int key, V oldValue, V newValue)
Replaces the entry for the specified key only if currently mapped to the specified value.Primitive specialized version of
Map.replace(Object, Object, Object)
.- Parameters:
key
- with which the specified value is associated.oldValue
- expected to be associated with the specified key.newValue
- to be associated with the specified key.- Returns:
true
if the value was replaced.
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replace
public V replace(java.lang.Integer key, V value)
- Specified by:
replace
in interfacejava.util.Map<java.lang.Integer,V>
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replace
public V replace(int key, V value)
Replaces the entry for the specified key only if it is currently mapped to some value.Primitive specialized version of
Map.replace(Object, Object)
.- Parameters:
key
- with which the specified value is associated.value
- to be associated with the specified key.- Returns:
- the previous value associated with the specified key.
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replaceAll
public void replaceAll(java.util.function.BiFunction<? super java.lang.Integer,? super V,? extends V> function)
- Specified by:
replaceAll
in interfacejava.util.Map<java.lang.Integer,V>
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replaceAllInt
public void replaceAllInt(IntObjectToObjectFunction<? super V,? extends V> function)
Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.Primitive specialized version of
Map.replaceAll(BiFunction)
.NB: Renamed from forEach to avoid overloading on parameter types of lambda expression, which doesn't play well with type inference in lambda expressions.
- Parameters:
function
- the function to apply to each entry.
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shuffleUp
private void shuffleUp(int fromIndex, int toIndex)
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shuffleDown
private void shuffleDown(int setBeginIndex)
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clear
public void clear()
Clear down all items in the cache.If an exception occurs during the eviction function callback then clear may need to be called again to complete.
If an exception occurs the cache should only be used when
size()
reports zero.- Specified by:
clear
in interfacejava.util.Map<java.lang.Integer,V>
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putAll
public void putAll(java.util.Map<? extends java.lang.Integer,? extends V> map)
- Specified by:
putAll
in interfacejava.util.Map<java.lang.Integer,V>
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putAll
public void putAll(Int2ObjectCache<? extends V> map)
Put all values from the given map into this one without allocation.- Parameters:
map
- whose value are to be added.
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keySet
public Int2ObjectCache.KeySet keySet()
- Specified by:
keySet
in interfacejava.util.Map<java.lang.Integer,V>
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values
public Int2ObjectCache.ValueCollection values()
- Specified by:
values
in interfacejava.util.Map<java.lang.Integer,V>
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entrySet
public Int2ObjectCache.EntrySet entrySet()
- Specified by:
entrySet
in interfacejava.util.Map<java.lang.Integer,V>
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toString
public java.lang.String toString()
- Overrides:
toString
in classjava.lang.Object
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equals
public boolean equals(java.lang.Object o)
- Specified by:
equals
in interfacejava.util.Map<java.lang.Integer,V>
- Overrides:
equals
in classjava.lang.Object
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hashCode
public int hashCode()
- Specified by:
hashCode
in interfacejava.util.Map<java.lang.Integer,V>
- Overrides:
hashCode
in classjava.lang.Object
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