Guava: Google Core Libraries for Java 33.1.0-jre · com.google.common.util.concurrent.AtomicLongMap

A map containing long values that can be atomically updated. While writes to a traditional Map rely on put(K, V), the typical mechanism for writing to this map is addAndGet(K, long), which adds a long to the value currently associated with K. If a key has not yet been associated with a value, its implicit value is zero.

Most methods in this class treat absent values and zero values identically, as individually documented. Exceptions to this are containsKey, size, isEmpty, asMap, and toString.

Instances of this class may be used by multiple threads concurrently. All operations are atomic unless otherwise noted.

Instances of this class are serializable if the keys are serializable.

Note

If your values are always positive and less than 2^31, you may wish to use a com.google.common.collect.Multiset such as com.google.common.collect.ConcurrentHashMultiset instead.

Warning

Unlike Multiset, entries whose values are zero are not automatically removed from the map. Instead they must be removed manually with removeAllZeros.

Field Summary

Modifier and Type	Field and Description
private transient Map<K, Long>	asMap
private final ConcurrentHashMap<K, Long>	map

Constructor Summary

Access	Constructor and Description
private	AtomicLongMap(ConcurrentHashMap<K, Long> map)

Method Summary

Modifier and Type	Method and Description
public long	accumulateAndGet(K key, long x, LongBinaryOperator accumulatorFunction) Updates the value currently associated with `key` by combining it with `x` via the specified accumulator function, returning the new value.
public long	addAndGet(K key, long delta) Adds `delta` to the value currently associated with `key`, and returns the new value.
public Map<K, Long>	asMap() Returns a live, read-only view of the map backing this `AtomicLongMap`.
public void	clear() Removes all of the mappings from this map.
public boolean	containsKey(Object key) Returns true if this map contains a mapping for the specified key.
public static <K> AtomicLongMap<K>	create() Creates an `AtomicLongMap`.
public static <K> AtomicLongMap<K>	create(Map<? extends K, ? extends Long> m) Creates an `AtomicLongMap` with the same mappings as the specified `Map`.
private Map<K, Long>	createAsMap()
public long	decrementAndGet(K key) Decrements by one the value currently associated with `key`, and returns the new value.
public long	get(K key) Returns the value associated with `key`, or zero if there is no value associated with `key`.
public long	getAndAccumulate(K key, long x, LongBinaryOperator accumulatorFunction) Updates the value currently associated with `key` by combining it with `x` via the specified accumulator function, returning the old value.
public long	getAndAdd(K key, long delta) Adds `delta` to the value currently associated with `key`, and returns the old value.
public long	getAndDecrement(K key) Decrements by one the value currently associated with `key`, and returns the old value.
public long	getAndIncrement(K key) Increments by one the value currently associated with `key`, and returns the old value.
public long	getAndUpdate(K key, LongUnaryOperator updaterFunction) Updates the value currently associated with `key` with the specified function, and returns the old value.
public long	incrementAndGet(K key) Increments by one the value currently associated with `key`, and returns the new value.
public boolean	isEmpty() Returns `true` if this map contains no key-value mappings.
public long	put(K key, long newValue) Associates `newValue` with `key` in this map, and returns the value previously associated with `key`, or zero if there was no such value.
public void	putAll(Map<? extends K, ? extends Long> m) Copies all of the mappings from the specified map to this map.
pack-priv long	putIfAbsent(K key, long newValue) If `key` is not already associated with a value or if `key` is associated with zero, associate it with `newValue`.
public long	remove(K key) Removes and returns the value associated with `key`.
pack-priv boolean	remove(K key, long value) If `(key, value)` is currently in the map, this method removes it and returns true; otherwise, this method returns false.
public void	removeAllZeros() Removes all mappings from this map whose values are zero.
public boolean	removeIfZero(K key) Atomically remove `key` from the map iff its associated value is 0.
pack-priv boolean	replace(K key, long expectedOldValue, long newValue) If `(key, expectedOldValue)` is currently in the map, this method replaces `expectedOldValue` with `newValue` and returns true; otherwise, this method returns false.
public int	size() Returns the number of key-value mappings in this map.
public long	sum() Returns the sum of all values in this map.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public long	updateAndGet(K key, LongUnaryOperator updaterFunction) Updates the value currently associated with `key` with the specified function, and returns the new value.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

asMap	back to summary
private transient Map<K, Long> asMap Annotations @LazyInit @CheckForNull

map	back to summary
private final ConcurrentHashMap<K, Long> map

Constructor Detail

AtomicLongMap	back to summary
private AtomicLongMap(ConcurrentHashMap<K, Long> map)

Method Detail

accumulateAndGet back to summary

accumulateAndGet	back to summary
public long accumulateAndGet(K key, long x, LongBinaryOperator accumulatorFunction) Updates the value currently associated with `key` by combining it with `x` via the specified accumulator function, returning the new value. The previous value associated with `key` (or zero, if there is none) is passed as the first argument to `accumulatorFunction`, and `x` is passed as the second argument. Annotations @CanIgnoreReturnValue Since 21.0

public long accumulateAndGet(K key, long x, LongBinaryOperator accumulatorFunction)

Updates the value currently associated with key by combining it with x via the specified accumulator function, returning the new value. The previous value associated with key (or zero, if there is none) is passed as the first argument to accumulatorFunction, and x is passed as the second argument.

Annotations

@CanIgnoreReturnValue

Since

21.0

addAndGet back to summary

addAndGet	back to summary
public long addAndGet(K key, long delta) Adds `delta` to the value currently associated with `key`, and returns the new value. Annotations @CanIgnoreReturnValue

public long addAndGet(K key, long delta)

Adds delta to the value currently associated with key, and returns the new value.

Annotations

@CanIgnoreReturnValue

asMap	back to summary
public Map<K, Long> asMap() Returns a live, read-only view of the map backing this `AtomicLongMap`.

clear	back to summary
public void clear() Removes all of the mappings from this map. The map will be empty after this call returns. This method is not atomic: the map may not be empty after returning if there were concurrent writes.

clear

back to summary

public void clear()

Removes all of the mappings from this map. The map will be empty after this call returns.

This method is not atomic: the map may not be empty after returning if there were concurrent writes.

containsKey	back to summary
public boolean containsKey(Object key) Returns true if this map contains a mapping for the specified key.

create	back to summary
public static <K> AtomicLongMap<K> create() Creates an `AtomicLongMap`.

create	back to summary
public static <K> AtomicLongMap<K> create(Map<? extends K, ? extends Long> m) Creates an `AtomicLongMap` with the same mappings as the specified `Map`.

createAsMap	back to summary
private Map<K, Long> createAsMap()

decrementAndGet back to summary

decrementAndGet	back to summary
public long decrementAndGet(K key) Decrements by one the value currently associated with `key`, and returns the new value. Annotations @CanIgnoreReturnValue

public long decrementAndGet(K key)

Decrements by one the value currently associated with key, and returns the new value.

Annotations

@CanIgnoreReturnValue

get	back to summary
public long get(K key) Returns the value associated with `key`, or zero if there is no value associated with `key`.

getAndAccumulate back to summary

getAndAccumulate	back to summary
public long getAndAccumulate(K key, long x, LongBinaryOperator accumulatorFunction) Updates the value currently associated with `key` by combining it with `x` via the specified accumulator function, returning the old value. The previous value associated with `key` (or zero, if there is none) is passed as the first argument to `accumulatorFunction`, and `x` is passed as the second argument. Annotations @CanIgnoreReturnValue Since 21.0

public long getAndAccumulate(K key, long x, LongBinaryOperator accumulatorFunction)

Updates the value currently associated with key by combining it with x via the specified accumulator function, returning the old value. The previous value associated with key (or zero, if there is none) is passed as the first argument to accumulatorFunction, and x is passed as the second argument.

Annotations

@CanIgnoreReturnValue

Since

21.0

getAndAdd back to summary

getAndAdd	back to summary
public long getAndAdd(K key, long delta) Adds `delta` to the value currently associated with `key`, and returns the old value. Annotations @CanIgnoreReturnValue

public long getAndAdd(K key, long delta)

Adds delta to the value currently associated with key, and returns the old value.

Annotations

@CanIgnoreReturnValue

getAndDecrement back to summary

getAndDecrement	back to summary
public long getAndDecrement(K key) Decrements by one the value currently associated with `key`, and returns the old value. Annotations @CanIgnoreReturnValue

public long getAndDecrement(K key)

Decrements by one the value currently associated with key, and returns the old value.

Annotations

@CanIgnoreReturnValue

getAndIncrement back to summary

getAndIncrement	back to summary
public long getAndIncrement(K key) Increments by one the value currently associated with `key`, and returns the old value. Annotations @CanIgnoreReturnValue

public long getAndIncrement(K key)

Increments by one the value currently associated with key, and returns the old value.

Annotations

@CanIgnoreReturnValue

getAndUpdate back to summary

getAndUpdate	back to summary
public long getAndUpdate(K key, LongUnaryOperator updaterFunction) Updates the value currently associated with `key` with the specified function, and returns the old value. If there is not currently a value associated with `key`, the function is applied to `0L`. Annotations @CanIgnoreReturnValue Since 21.0

public long getAndUpdate(K key, LongUnaryOperator updaterFunction)

Updates the value currently associated with key with the specified function, and returns the old value. If there is not currently a value associated with key, the function is applied to 0L.

Annotations

@CanIgnoreReturnValue

Since

21.0

incrementAndGet back to summary

incrementAndGet	back to summary
public long incrementAndGet(K key) Increments by one the value currently associated with `key`, and returns the new value. Annotations @CanIgnoreReturnValue

public long incrementAndGet(K key)

Increments by one the value currently associated with key, and returns the new value.

Annotations

@CanIgnoreReturnValue

isEmpty	back to summary
public boolean isEmpty() Returns `true` if this map contains no key-value mappings.

put back to summary

put	back to summary
public long put(K key, long newValue) Associates `newValue` with `key` in this map, and returns the value previously associated with `key`, or zero if there was no such value. Annotations @CanIgnoreReturnValue

public long put(K key, long newValue)

Associates newValue with key in this map, and returns the value previously associated with key, or zero if there was no such value.

Annotations

@CanIgnoreReturnValue

putAll	back to summary
public void putAll(Map<? extends K, ? extends Long> m) Copies all of the mappings from the specified map to this map. The effect of this call is equivalent to that of calling `put(k, v)` on this map once for each mapping from key `k` to value `v` in the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress.

putIfAbsent	back to summary
pack-priv long putIfAbsent(K key, long newValue) If `key` is not already associated with a value or if `key` is associated with zero, associate it with `newValue`. Returns the previous value associated with `key`, or zero if there was no mapping for `key`.

remove back to summary

remove	back to summary
public long remove(K key) Removes and returns the value associated with `key`. If `key` is not in the map, this method has no effect and returns zero. Annotations @CanIgnoreReturnValue

public long remove(K key)

Removes and returns the value associated with key. If key is not in the map, this method has no effect and returns zero.

Annotations

@CanIgnoreReturnValue

remove	back to summary
pack-priv boolean remove(K key, long value) If `(key, value)` is currently in the map, this method removes it and returns true; otherwise, this method returns false.

removeAllZeros	back to summary
public void removeAllZeros() Removes all mappings from this map whose values are zero. This method is not atomic: the map may be visible in intermediate states, where some of the zero values have been removed and others have not.

removeAllZeros

back to summary

public void removeAllZeros()

Removes all mappings from this map whose values are zero.

This method is not atomic: the map may be visible in intermediate states, where some of the zero values have been removed and others have not.

removeIfZero back to summary

removeIfZero	back to summary
public boolean removeIfZero(K key) Atomically remove `key` from the map iff its associated value is 0. Annotations @CanIgnoreReturnValue Since 20.0

public boolean removeIfZero(K key)

Atomically remove key from the map iff its associated value is 0.

Annotations

@CanIgnoreReturnValue

Since

20.0

replace back to summary

replace	back to summary
pack-priv boolean replace(K key, long expectedOldValue, long newValue) If `(key, expectedOldValue)` is currently in the map, this method replaces `expectedOldValue` with `newValue` and returns true; otherwise, this method returns false. If `expectedOldValue` is zero, this method will succeed if `(key, zero)` is currently in the map, or if `key` is not in the map at all.

pack-priv boolean replace(K key, long expectedOldValue, long newValue)

If (key, expectedOldValue) is currently in the map, this method replaces expectedOldValue with newValue and returns true; otherwise, this method returns false.

If expectedOldValue is zero, this method will succeed if (key, zero) is currently in the map, or if key is not in the map at all.

size	back to summary
public int size() Returns the number of key-value mappings in this map. If the map contains more than `Integer.MAX_VALUE` elements, returns `Integer.MAX_VALUE`.

sum	back to summary
public long sum() Returns the sum of all values in this map. This method is not atomic: the sum may or may not include other concurrent operations.

sum

back to summary

public long sum()

Returns the sum of all values in this map.

This method is not atomic: the sum may or may not include other concurrent operations.

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object

Annotations

@Override

updateAndGet back to summary

updateAndGet	back to summary
public long updateAndGet(K key, LongUnaryOperator updaterFunction) Updates the value currently associated with `key` with the specified function, and returns the new value. If there is not currently a value associated with `key`, the function is applied to `0L`. Annotations @CanIgnoreReturnValue Since 21.0

public long updateAndGet(K key, LongUnaryOperator updaterFunction)

Updates the value currently associated with key with the specified function, and returns the new value. If there is not currently a value associated with key, the function is applied to 0L.

Annotations

@CanIgnoreReturnValue

Since

21.0

public final Class AtomicLongMap<K>

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail