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jdk.util.concurrent.ConcurrentHashMap

A hash table supporting full concurrency of retrievals and high expected concurrency for updates. This class obeys the same functional specification as Hashtable, and includes versions of methods corresponding to each method of Hashtable. However, even though all operations are thread-safe, retrieval operations do not entail locking, and there is not any support for locking the entire table in a way that prevents all access. This class is fully interoperable with Hashtable in programs that rely on its thread safety but not on its synchronization details.

Retrieval operations (including get) generally do not block, so may overlap with update operations (including put and remove). Retrievals reflect the results of the most recently completed update operations holding upon their onset. (More formally, an update operation for a given key bears a happens-before relation with any (non-null) retrieval for that key reporting the updated value.) For aggregate operations such as putAll and clear, concurrent retrievals may reflect insertion or removal of only some entries. Similarly, Iterators, Spliterators and Enumerations return elements reflecting the state of the hash table at some point at or since the creation of the iterator/enumeration. They do not throw ConcurrentModificationException. However, iterators are designed to be used by only one thread at a time. Bear in mind that the results of aggregate status methods including size, isEmpty, and containsValue are typically useful only when a map is not undergoing concurrent updates in other threads. Otherwise the results of these methods reflect transient states that may be adequate for monitoring or estimation purposes, but not for program control.

The table is dynamically expanded when there are too many collisions (i.e., keys that have distinct hash codes but fall into the same slot modulo the table size), with the expected average effect of maintaining roughly two bins per mapping (corresponding to a 0.75 load factor threshold for resizing). There may be much variance around this average as mappings are added and removed, but overall, this maintains a commonly accepted time/space tradeoff for hash tables. However, resizing this or any other kind of hash table may be a relatively slow operation. When possible, it is a good idea to provide a size estimate as an optional initialCapacity constructor argument. An additional optional loadFactor constructor argument provides a further means of customizing initial table capacity by specifying the table density to be used in calculating the amount of space to allocate for the given number of elements. Also, for compatibility with previous versions of this class, constructors may optionally specify an expected concurrencyLevel as an additional hint for internal sizing. Note that using many keys with exactly the same hashCode() is a sure way to slow down performance of any hash table. To ameliorate impact, when keys are Comparable, this class may use comparison order among keys to help break ties.

A Set projection of a ConcurrentHashMap may be created (using newKeySet() or newKeySet(int)), or viewed (using keySet(Object) when only keys are of interest, and the mapped values are (perhaps transiently) not used or all take the same mapping value.

A ConcurrentHashMap can be used as scalable frequency map (a form of histogram or multiset) by using LongAdder values and initializing via computeIfAbsent. For example, to add a count to a ConcurrentHashMap<String,LongAdder> freqs, you can use freqs.computeIfAbsent(k -> new LongAdder()).increment();

This class and its views and iterators implement all of the optional methods of the Map and Iterator interfaces.

Like Hashtable but unlike HashMap, this class does not allow null to be used as a key or value.

ConcurrentHashMaps support a set of sequential and parallel bulk operations that, unlike most Stream methods, are designed to be safely, and often sensibly, applied even with maps that are being concurrently updated by other threads; for example, when computing a snapshot summary of the values in a shared registry. There are three kinds of operation, each with four forms, accepting functions with Keys, Values, Entries, and (Key, Value) arguments and/or return values. Because the elements of a ConcurrentHashMap are not ordered in any particular way, and may be processed in different orders in different parallel executions, the correctness of supplied functions should not depend on any ordering, or on any other objects or values that may transiently change while computation is in progress; and except for forEach actions, should ideally be side-effect-free. Bulk operations on Map.Entry objects do not support method setValue.

forEach: Perform a given action on each element. A variant form applies a given transformation on each element before performing the action.

search: Return the first available non-null result of applying a given function on each element; skipping further search when a result is found.

reduce: Accumulate each element. The supplied reduction function cannot rely on ordering (more formally, it should be both associative and commutative). There are five variants:

Plain reductions. (There is not a form of this method for (key, value) function arguments since there is no corresponding return type.)

Mapped reductions that accumulate the results of a given function applied to each element.

Reductions to scalar doubles, longs, and ints, using a given basis value.

These bulk operations accept a parallelismThreshold argument. Methods proceed sequentially if the current map size is estimated to be less than the given threshold. Using a value of Long.MAX_VALUE suppresses all parallelism. Using a value of 1 results in maximal parallelism by partitioning into enough subtasks to fully utilize the ForkJoinPool.commonPool() that is used for all parallel computations. Normally, you would initially choose one of these extreme values, and then measure performance of using in-between values that trade off overhead versus throughput.

The concurrency properties of bulk operations follow from those of ConcurrentHashMap: Any non-null result returned from get(key) and related access methods bears a happens-before relation with the associated insertion or update. The result of any bulk operation reflects the composition of these per-element relations (but is not necessarily atomic with respect to the map as a whole unless it is somehow known to be quiescent). Conversely, because keys and values in the map are never null, null serves as a reliable atomic indicator of the current lack of any result. To maintain this property, null serves as an implicit basis for all non-scalar reduction operations. For the double, long, and int versions, the basis should be one that, when combined with any other value, returns that other value (more formally, it should be the identity element for the reduction). Most common reductions have these properties; for example, computing a sum with basis 0 or a minimum with basis MAX_VALUE.

Search and transformation functions provided as arguments should similarly return null to indicate the lack of any result (in which case it is not used). In the case of mapped reductions, this also enables transformations to serve as filters, returning null (or, in the case of primitive specializations, the identity basis) if the element should not be combined. You can create compound transformations and filterings by composing them yourself under this "null means there is nothing there now" rule before using them in search or reduce operations.

Methods accepting and/or returning Entry arguments maintain key-value associations. They may be useful for example when finding the key for the greatest value. Note that "plain" Entry arguments can be supplied using new AbstractMap.SimpleEntry(k,v).

Bulk operations may complete abruptly, throwing an exception encountered in the application of a supplied function. Bear in mind when handling such exceptions that other concurrently executing functions could also have thrown exceptions, or would have done so if the first exception had not occurred.

Speedups for parallel compared to sequential forms are common but not guaranteed. Parallel operations involving brief functions on small maps may execute more slowly than sequential forms if the underlying work to parallelize the computation is more expensive than the computation itself. Similarly, parallelization may not lead to much actual parallelism if all processors are busy performing unrelated tasks.

All arguments to all task methods must be non-null.

This class is a member of the

Java Collections Framework.

A hash table supporting full concurrency of retrievals and
high expected concurrency for updates. This class obeys the
same functional specification as Hashtable, and
includes versions of methods corresponding to each method of
Hashtable. However, even though all operations are
thread-safe, retrieval operations do not entail locking,
and there is not any support for locking the entire table
in a way that prevents all access.  This class is fully
interoperable with Hashtable in programs that rely on its
thread safety but not on its synchronization details.

Retrieval operations (including get) generally do not
block, so may overlap with update operations (including put
and remove). Retrievals reflect the results of the most
recently completed update operations holding upon their
onset. (More formally, an update operation for a given key bears a
happens-before relation with any (non-null) retrieval for
that key reporting the updated value.)  For aggregate operations
such as putAll and clear, concurrent retrievals may
reflect insertion or removal of only some entries.  Similarly,
Iterators, Spliterators and Enumerations return elements reflecting the
state of the hash table at some point at or since the creation of the
iterator/enumeration.  They do not throw ConcurrentModificationException.
However, iterators are designed to be used by only one thread at a time.
Bear in mind that the results of aggregate status methods including
size, isEmpty, and containsValue are typically
useful only when a map is not undergoing concurrent updates in other threads.
Otherwise the results of these methods reflect transient states
that may be adequate for monitoring or estimation purposes, but not
for program control.

The table is dynamically expanded when there are too many
collisions (i.e., keys that have distinct hash codes but fall into
the same slot modulo the table size), with the expected average
effect of maintaining roughly two bins per mapping (corresponding
to a 0.75 load factor threshold for resizing). There may be much
variance around this average as mappings are added and removed, but
overall, this maintains a commonly accepted time/space tradeoff for
hash tables.  However, resizing this or any other kind of hash
table may be a relatively slow operation. When possible, it is a
good idea to provide a size estimate as an optional initialCapacity constructor argument. An additional optional
loadFactor constructor argument provides a further means of
customizing initial table capacity by specifying the table density
to be used in calculating the amount of space to allocate for the
given number of elements.  Also, for compatibility with previous
versions of this class, constructors may optionally specify an
expected concurrencyLevel as an additional hint for
internal sizing.  Note that using many keys with exactly the same
hashCode() is a sure way to slow down performance of any
hash table. To ameliorate impact, when keys are Comparable,
this class may use comparison order among keys to help break ties.

A Set projection of a ConcurrentHashMap may be created
(using newKeySet() or newKeySet(int)), or viewed
(using keySet(Object) when only keys are of interest, and the
mapped values are (perhaps transiently) not used or all take the
same mapping value.

A ConcurrentHashMap can be used as scalable frequency map (a
form of histogram or multiset) by using LongAdder values and initializing via
computeIfAbsent. For example, to add a count
to a ConcurrentHashMap<String,LongAdder> freqs, you can use
freqs.computeIfAbsent(k -> new LongAdder()).increment();

This class and its views and iterators implement all of the
optional methods of the Map and Iterator
interfaces.

Like Hashtable but unlike HashMap, this class
does not allow null to be used as a key or value.

ConcurrentHashMaps support a set of sequential and parallel bulk
operations that, unlike most Stream methods, are designed
to be safely, and often sensibly, applied even with maps that are
being concurrently updated by other threads; for example, when
computing a snapshot summary of the values in a shared registry.
There are three kinds of operation, each with four forms, accepting
functions with Keys, Values, Entries, and (Key, Value) arguments
and/or return values. Because the elements of a ConcurrentHashMap
are not ordered in any particular way, and may be processed in
different orders in different parallel executions, the correctness
of supplied functions should not depend on any ordering, or on any
other objects or values that may transiently change while
computation is in progress; and except for forEach actions, should
ideally be side-effect-free. Bulk operations on Map.Entry
objects do not support method setValue.


 forEach: Perform a given action on each element.
A variant form applies a given transformation on each element
before performing the action.

 search: Return the first available non-null result of
applying a given function on each element; skipping further
search when a result is found.

 reduce: Accumulate each element.  The supplied reduction
function cannot rely on ordering (more formally, it should be
both associative and commutative).  There are five variants:



 Plain reductions. (There is not a form of this method for
(key, value) function arguments since there is no corresponding
return type.)

 Mapped reductions that accumulate the results of a given
function applied to each element.

 Reductions to scalar doubles, longs, and ints, using a
given basis value.





These bulk operations accept a parallelismThreshold
argument. Methods proceed sequentially if the current map size is
estimated to be less than the given threshold. Using a value of
Long.MAX_VALUE suppresses all parallelism.  Using a value
of 1 results in maximal parallelism by partitioning into
enough subtasks to fully utilize the ForkJoinPool.commonPool() that is used for all parallel
computations. Normally, you would initially choose one of these
extreme values, and then measure performance of using in-between
values that trade off overhead versus throughput.

The concurrency properties of bulk operations follow
from those of ConcurrentHashMap: Any non-null result returned
from get(key) and related access methods bears a
happens-before relation with the associated insertion or
update.  The result of any bulk operation reflects the
composition of these per-element relations (but is not
necessarily atomic with respect to the map as a whole unless it
is somehow known to be quiescent).  Conversely, because keys
and values in the map are never null, null serves as a reliable
atomic indicator of the current lack of any result.  To
maintain this property, null serves as an implicit basis for
all non-scalar reduction operations. For the double, long, and
int versions, the basis should be one that, when combined with
any other value, returns that other value (more formally, it
should be the identity element for the reduction). Most common
reductions have these properties; for example, computing a sum
with basis 0 or a minimum with basis MAX_VALUE.

Search and transformation functions provided as arguments
should similarly return null to indicate the lack of any result
(in which case it is not used). In the case of mapped
reductions, this also enables transformations to serve as
filters, returning null (or, in the case of primitive
specializations, the identity basis) if the element should not
be combined. You can create compound transformations and
filterings by composing them yourself under this "null means
there is nothing there now" rule before using them in search or
reduce operations.

Methods accepting and/or returning Entry arguments maintain
key-value associations. They may be useful for example when
finding the key for the greatest value. Note that "plain" Entry
arguments can be supplied using new
AbstractMap.SimpleEntry(k,v).

Bulk operations may complete abruptly, throwing an
exception encountered in the application of a supplied
function. Bear in mind when handling such exceptions that other
concurrently executing functions could also have thrown
exceptions, or would have done so if the first exception had
not occurred.

Speedups for parallel compared to sequential forms are common
but not guaranteed.  Parallel operations involving brief functions
on small maps may execute more slowly than sequential forms if the
underlying work to parallelize the computation is more expensive
than the computation itself.  Similarly, parallelization may not
lead to much actual parallelism if all processors are busy
performing unrelated tasks.

All arguments to all task methods must be non-null.

This class is a member of the

Java Collections Framework.
raw docstring

*new-key-setclj

(*new-key-set)
(*new-key-set initial-capacity)

Creates a new Set backed by a ConcurrentHashMap from the given type to Boolean.TRUE.

initial-capacity - The implementation performs internal sizing to accommodate this many elements. - int

returns: the new set - <K> java.util.concurrent.ConcurrentHashMap$KeySetView<K,java.lang.Boolean>

throws: java.lang.IllegalArgumentException - if the initial capacity of elements is negative

Creates a new Set backed by a ConcurrentHashMap
 from the given type to Boolean.TRUE.

initial-capacity - The implementation performs internal sizing to accommodate this many elements. - `int`

returns: the new set - `<K> java.util.concurrent.ConcurrentHashMap$KeySetView<K,java.lang.Boolean>`

throws: java.lang.IllegalArgumentException - if the initial capacity of elements is negative
raw docstring

->concurrent-hash-mapclj

(->concurrent-hash-map)
(->concurrent-hash-map initial-capacity)
(->concurrent-hash-map initial-capacity load-factor)
(->concurrent-hash-map initial-capacity load-factor concurrency-level)

Constructor.

Creates a new, empty map with an initial table size based on the given number of elements (initialCapacity), table density (loadFactor), and number of concurrently updating threads (concurrencyLevel).

initial-capacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements, given the specified load factor. - int load-factor - the load factor (table density) for establishing the initial table size - float concurrency-level - the estimated number of concurrently updating threads. The implementation may use this value as a sizing hint. - int

throws: java.lang.IllegalArgumentException - if the initial capacity is negative or the load factor or concurrencyLevel are nonpositive

Constructor.

Creates a new, empty map with an initial table size based on
 the given number of elements (initialCapacity), table
 density (loadFactor), and number of concurrently
 updating threads (concurrencyLevel).

initial-capacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements, given the specified load factor. - `int`
load-factor - the load factor (table density) for establishing the initial table size - `float`
concurrency-level - the estimated number of concurrently updating threads. The implementation may use this value as a sizing hint. - `int`

throws: java.lang.IllegalArgumentException - if the initial capacity is negative or the load factor or concurrencyLevel are nonpositive
raw docstring

clearclj

(clear this)

Removes all of the mappings from this map.

Removes all of the mappings from this map.
raw docstring

computeclj

(compute this key remapping-function)

Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). The entire method invocation is performed atomically. Some attempted update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and simple, and must not attempt to update any other mappings of this Map.

key - key with which the specified value is to be associated - K remapping-function - the function to compute a value - java.util.function.BiFunction

returns: the new value associated with the specified key, or null if none - V

throws: java.lang.NullPointerException - if the specified key or remappingFunction is null

Attempts to compute a mapping for the specified key and its
 current mapped value (or null if there is no current
 mapping). The entire method invocation is performed atomically.
 Some attempted update operations on this map by other threads
 may be blocked while computation is in progress, so the
 computation should be short and simple, and must not attempt to
 update any other mappings of this Map.

key - key with which the specified value is to be associated - `K`
remapping-function - the function to compute a value - `java.util.function.BiFunction`

returns: the new value associated with the specified key, or null if none - `V`

throws: java.lang.NullPointerException - if the specified key or remappingFunction is null
raw docstring

compute-if-absentclj

(compute-if-absent this key mapping-function)

If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless null. The entire method invocation is performed atomically, so the function is applied at most once per key. Some attempted update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and simple, and must not attempt to update any other mappings of this map.

key - key with which the specified value is to be associated - K mapping-function - the function to compute a value - java.util.function.Function

returns: the current (existing or computed) value associated with the specified key, or null if the computed value is null - V

throws: java.lang.NullPointerException - if the specified key or mappingFunction is null

If the specified key is not already associated with a value,
 attempts to compute its value using the given mapping function
 and enters it into this map unless null.  The entire
 method invocation is performed atomically, so the function is
 applied at most once per key.  Some attempted update operations
 on this map by other threads may be blocked while computation
 is in progress, so the computation should be short and simple,
 and must not attempt to update any other mappings of this map.

key - key with which the specified value is to be associated - `K`
mapping-function - the function to compute a value - `java.util.function.Function`

returns: the current (existing or computed) value associated with
         the specified key, or null if the computed value is null - `V`

throws: java.lang.NullPointerException - if the specified key or mappingFunction is null
raw docstring

compute-if-presentclj

(compute-if-present this key remapping-function)

If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value. The entire method invocation is performed atomically. Some attempted update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and simple, and must not attempt to update any other mappings of this map.

key - key with which a value may be associated - K remapping-function - the function to compute a value - java.util.function.BiFunction

returns: the new value associated with the specified key, or null if none - V

throws: java.lang.NullPointerException - if the specified key or remappingFunction is null

If the value for the specified key is present, attempts to
 compute a new mapping given the key and its current mapped
 value.  The entire method invocation is performed atomically.
 Some attempted update operations on this map by other threads
 may be blocked while computation is in progress, so the
 computation should be short and simple, and must not attempt to
 update any other mappings of this map.

key - key with which a value may be associated - `K`
remapping-function - the function to compute a value - `java.util.function.BiFunction`

returns: the new value associated with the specified key, or null if none - `V`

throws: java.lang.NullPointerException - if the specified key or remappingFunction is null
raw docstring

containsclj

(contains this value)

Legacy method testing if some key maps into the specified value in this table. This method is identical in functionality to containsValue(Object), and exists solely to ensure full compatibility with class Hashtable, which supported this method prior to introduction of the Java Collections framework.

value - a value to search for - java.lang.Object

returns: true if and only if some key maps to the value argument in this table as determined by the equals method; false otherwise - boolean

throws: java.lang.NullPointerException - if the specified value is null

Legacy method testing if some key maps into the specified value
 in this table.  This method is identical in functionality to
 containsValue(Object), and exists solely to ensure
 full compatibility with class Hashtable,
 which supported this method prior to introduction of the
 Java Collections framework.

value - a value to search for - `java.lang.Object`

returns: true if and only if some key maps to the
         value argument in this table as
         determined by the equals method;
         false otherwise - `boolean`

throws: java.lang.NullPointerException - if the specified value is null
raw docstring

contains-keyclj

(contains-key this key)

Tests if the specified object is a key in this table.

key - possible key - java.lang.Object

returns: true if and only if the specified object is a key in this table, as determined by the equals method; false otherwise - boolean

throws: java.lang.NullPointerException - if the specified key is null

Tests if the specified object is a key in this table.

key - possible key - `java.lang.Object`

returns: true if and only if the specified object
         is a key in this table, as determined by the
         equals method; false otherwise - `boolean`

throws: java.lang.NullPointerException - if the specified key is null
raw docstring

contains-valueclj

(contains-value this value)

Returns true if this map maps one or more keys to the specified value. Note: This method may require a full traversal of the map, and is much slower than method containsKey.

value - value whose presence in this map is to be tested - java.lang.Object

returns: true if this map maps one or more keys to the specified value - boolean

throws: java.lang.NullPointerException - if the specified value is null

Returns true if this map maps one or more keys to the
 specified value. Note: This method may require a full traversal
 of the map, and is much slower than method containsKey.

value - value whose presence in this map is to be tested - `java.lang.Object`

returns: true if this map maps one or more keys to the
         specified value - `boolean`

throws: java.lang.NullPointerException - if the specified value is null
raw docstring

elementsclj

(elements this)

Returns an enumeration of the values in this table.

returns: an enumeration of the values in this table - java.util.Enumeration<V>

Returns an enumeration of the values in this table.

returns: an enumeration of the values in this table - `java.util.Enumeration<V>`
raw docstring

empty?clj

(empty? this)

Returns true if this map contains no key-value mappings.

returns: true if this map contains no key-value mappings - boolean

Returns true if this map contains no key-value mappings.

returns: true if this map contains no key-value mappings - `boolean`
raw docstring

entry-setclj

(entry-set this)

Returns a Set view of the mappings contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations.

The view's iterators and spliterators are weakly consistent.

The view's spliterator reports Spliterator.CONCURRENT, Spliterator.DISTINCT, and Spliterator.NONNULL.

returns: the set view - java.util.Set<java.util.Map$Entry<K,V>>

Returns a Set view of the mappings contained in this map.
 The set is backed by the map, so changes to the map are
 reflected in the set, and vice-versa.  The set supports element
 removal, which removes the corresponding mapping from the map,
 via the Iterator.remove, Set.remove,
 removeAll, retainAll, and clear
 operations.

 The view's iterators and spliterators are
 weakly consistent.

 The view's spliterator reports Spliterator.CONCURRENT,
 Spliterator.DISTINCT, and Spliterator.NONNULL.

returns: the set view - `java.util.Set<java.util.Map$Entry<K,V>>`
raw docstring

equalsclj

(equals this o)

Compares the specified object with this map for equality. Returns true if the given object is a map with the same mappings as this map. This operation may return misleading results if either map is concurrently modified during execution of this method.

o - object to be compared for equality with this map - java.lang.Object

returns: true if the specified object is equal to this map - boolean

Compares the specified object with this map for equality.
 Returns true if the given object is a map with the same
 mappings as this map.  This operation may return misleading
 results if either map is concurrently modified during execution
 of this method.

o - object to be compared for equality with this map - `java.lang.Object`

returns: true if the specified object is equal to this map - `boolean`
raw docstring

for-eachclj

(for-each this action)
(for-each this parallelism-threshold action)
(for-each this parallelism-threshold transformer action)

Performs the given action for each non-null transformation of each (key, value).

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - java.util.function.BiFunction action - the action - java.util.function.Consumer

returns: <U> void

Performs the given action for each non-null transformation
 of each (key, value).

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - `java.util.function.BiFunction`
action - the action - `java.util.function.Consumer`

returns: `<U> void`
raw docstring

for-each-entryclj

(for-each-entry this parallelism-threshold action)
(for-each-entry this parallelism-threshold transformer action)

Performs the given action for each non-null transformation of each entry.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - java.util.function.Function action - the action - java.util.function.Consumer

returns: <U> void

Performs the given action for each non-null transformation
 of each entry.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - `java.util.function.Function`
action - the action - `java.util.function.Consumer`

returns: `<U> void`
raw docstring

for-each-keyclj

(for-each-key this parallelism-threshold action)
(for-each-key this parallelism-threshold transformer action)

Performs the given action for each non-null transformation of each key.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - java.util.function.Function action - the action - java.util.function.Consumer

returns: <U> void

Performs the given action for each non-null transformation
 of each key.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - `java.util.function.Function`
action - the action - `java.util.function.Consumer`

returns: `<U> void`
raw docstring

for-each-valueclj

(for-each-value this parallelism-threshold action)
(for-each-value this parallelism-threshold transformer action)

Performs the given action for each non-null transformation of each value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - java.util.function.Function action - the action - java.util.function.Consumer

returns: <U> void

Performs the given action for each non-null transformation
 of each value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case the action is not applied) - `java.util.function.Function`
action - the action - `java.util.function.Consumer`

returns: `<U> void`
raw docstring

getclj

(get this key)

Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.

More formally, if this map contains a mapping from a key k to a value v such that key.equals(k), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

key - the key whose associated value is to be returned - java.lang.Object

returns: the value to which the specified key is mapped, or null if this map contains no mapping for the key - V

throws: java.lang.NullPointerException - if the specified key is null

Returns the value to which the specified key is mapped,
 or null if this map contains no mapping for the key.

 More formally, if this map contains a mapping from a key
 k to a value v such that key.equals(k),
 then this method returns v; otherwise it returns
 null.  (There can be at most one such mapping.)

key - the key whose associated value is to be returned - `java.lang.Object`

returns: the value to which the specified key is mapped, or
         null if this map contains no mapping for the key - `V`

throws: java.lang.NullPointerException - if the specified key is null
raw docstring

get-or-defaultclj

(get-or-default this key default-value)

Returns the value to which the specified key is mapped, or the given default value if this map contains no mapping for the key.

key - the key whose associated value is to be returned - java.lang.Object default-value - the value to return if this map contains no mapping for the given key - V

returns: the mapping for the key, if present; else the default value - V

throws: java.lang.NullPointerException - if the specified key is null

Returns the value to which the specified key is mapped, or the
 given default value if this map contains no mapping for the
 key.

key - the key whose associated value is to be returned - `java.lang.Object`
default-value - the value to return if this map contains no mapping for the given key - `V`

returns: the mapping for the key, if present; else the default value - `V`

throws: java.lang.NullPointerException - if the specified key is null
raw docstring

hash-codeclj

(hash-code this)

Returns the hash code value for this Map, i.e., the sum of, for each key-value pair in the map, key.hashCode() ^ value.hashCode().

returns: the hash code value for this map - int

Returns the hash code value for this Map, i.e.,
 the sum of, for each key-value pair in the map,
 key.hashCode() ^ value.hashCode().

returns: the hash code value for this map - `int`
raw docstring

key-setclj

(key-set this)
(key-set this mapped-value)

Returns a Set view of the keys in this map, using the given common mapped value for any additions (i.e., Collection.add(E) and Collection.addAll(Collection)). This is of course only appropriate if it is acceptable to use the same value for all additions from this view.

mapped-value - the mapped value to use for any additions - V

returns: the set view - java.util.concurrent.ConcurrentHashMap$KeySetView<K,V>

throws: java.lang.NullPointerException - if the mappedValue is null

Returns a Set view of the keys in this map, using the
 given common mapped value for any additions (i.e., Collection.add(E) and Collection.addAll(Collection)).
 This is of course only appropriate if it is acceptable to use
 the same value for all additions from this view.

mapped-value - the mapped value to use for any additions - `V`

returns: the set view - `java.util.concurrent.ConcurrentHashMap$KeySetView<K,V>`

throws: java.lang.NullPointerException - if the mappedValue is null
raw docstring

keysclj

(keys this)

Returns an enumeration of the keys in this table.

returns: an enumeration of the keys in this table - java.util.Enumeration<K>

Returns an enumeration of the keys in this table.

returns: an enumeration of the keys in this table - `java.util.Enumeration<K>`
raw docstring

mapping-countclj

(mapping-count this)

Returns the number of mappings. This method should be used instead of size() because a ConcurrentHashMap may contain more mappings than can be represented as an int. The value returned is an estimate; the actual count may differ if there are concurrent insertions or removals.

returns: the number of mappings - long

Returns the number of mappings. This method should be used
 instead of size() because a ConcurrentHashMap may
 contain more mappings than can be represented as an int. The
 value returned is an estimate; the actual count may differ if
 there are concurrent insertions or removals.

returns: the number of mappings - `long`
raw docstring

mergeclj

(merge this key value remapping-function)

If the specified key is not already associated with a (non-null) value, associates it with the given value. Otherwise, replaces the value with the results of the given remapping function, or removes if null. The entire method invocation is performed atomically. Some attempted update operations on this map by other threads may be blocked while computation is in progress, so the computation should be short and simple, and must not attempt to update any other mappings of this Map.

key - key with which the specified value is to be associated - K value - the value to use if absent - V remapping-function - the function to recompute a value if present - java.util.function.BiFunction

returns: the new value associated with the specified key, or null if none - V

throws: java.lang.NullPointerException - if the specified key or the remappingFunction is null

If the specified key is not already associated with a
 (non-null) value, associates it with the given value.
 Otherwise, replaces the value with the results of the given
 remapping function, or removes if null. The entire
 method invocation is performed atomically.  Some attempted
 update operations on this map by other threads may be blocked
 while computation is in progress, so the computation should be
 short and simple, and must not attempt to update any other
 mappings of this Map.

key - key with which the specified value is to be associated - `K`
value - the value to use if absent - `V`
remapping-function - the function to recompute a value if present - `java.util.function.BiFunction`

returns: the new value associated with the specified key, or null if none - `V`

throws: java.lang.NullPointerException - if the specified key or the remappingFunction is null
raw docstring

putclj

(put this key value)

Maps the specified key to the specified value in this table. Neither the key nor the value can be null.

The value can be retrieved by calling the get method with a key that is equal to the original key.

key - key with which the specified value is to be associated - K value - value to be associated with the specified key - V

returns: the previous value associated with key, or null if there was no mapping for key - V

throws: java.lang.NullPointerException - if the specified key or value is null

Maps the specified key to the specified value in this table.
 Neither the key nor the value can be null.

 The value can be retrieved by calling the get method
 with a key that is equal to the original key.

key - key with which the specified value is to be associated - `K`
value - value to be associated with the specified key - `V`

returns: the previous value associated with key, or
         null if there was no mapping for key - `V`

throws: java.lang.NullPointerException - if the specified key or value is null
raw docstring

put-allclj

(put-all this m)

Copies all of the mappings from the specified map to this one. These mappings replace any mappings that this map had for any of the keys currently in the specified map.

m - mappings to be stored in this map - java.util.Map

Copies all of the mappings from the specified map to this one.
 These mappings replace any mappings that this map had for any of the
 keys currently in the specified map.

m - mappings to be stored in this map - `java.util.Map`
raw docstring

put-if-absentclj

(put-if-absent this key value)

If the specified key is not already associated with a value, associate it with the given value. This is equivalent to

if (!map.containsKey(key)) return map.put(key, value); else return map.get(key);

except that the action is performed atomically.

key - key with which the specified value is to be associated - K value - value to be associated with the specified key - V

returns: the previous value associated with the specified key, or null if there was no mapping for the key - V

throws: java.lang.NullPointerException - if the specified key or value is null

If the specified key is not already associated
 with a value, associate it with the given value.
 This is equivalent to


 if (!map.containsKey(key))
   return map.put(key, value);
 else
   return map.get(key);

 except that the action is performed atomically.

key - key with which the specified value is to be associated - `K`
value - value to be associated with the specified key - `V`

returns: the previous value associated with the specified key,
         or null if there was no mapping for the key - `V`

throws: java.lang.NullPointerException - if the specified key or value is null
raw docstring

reduceclj

(reduce this parallelism-threshold transformer reducer)

Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - java.util.function.BiFunction reducer - a commutative associative combining function - java.util.function.BiFunction

returns: the result of accumulating the given transformation of all (key, value) pairs - <U> U

Returns the result of accumulating the given transformation
 of all (key, value) pairs using the given reducer to
 combine values, or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - `java.util.function.BiFunction`
reducer - a commutative associative combining function - `java.util.function.BiFunction`

returns: the result of accumulating the given transformation
 of all (key, value) pairs - `<U> U`
raw docstring

reduce-entriesclj

(reduce-entries this parallelism-threshold reducer)
(reduce-entries this parallelism-threshold transformer reducer)

Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - java.util.function.Function reducer - a commutative associative combining function - java.util.function.BiFunction

returns: the result of accumulating the given transformation of all entries - <U> U

Returns the result of accumulating the given transformation
 of all entries using the given reducer to combine values,
 or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - `java.util.function.Function`
reducer - a commutative associative combining function - `java.util.function.BiFunction`

returns: the result of accumulating the given transformation
 of all entries - `<U> U`
raw docstring

reduce-entries-to-doubleclj

(reduce-entries-to-double this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToDoubleFunction basis - the identity (initial default value) for the reduction - double reducer - a commutative associative combining function - java.util.function.DoubleBinaryOperator

returns: the result of accumulating the given transformation of all entries - double

Returns the result of accumulating the given transformation
 of all entries using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToDoubleFunction`
basis - the identity (initial default value) for the reduction - `double`
reducer - a commutative associative combining function - `java.util.function.DoubleBinaryOperator`

returns: the result of accumulating the given transformation
 of all entries - `double`
raw docstring

reduce-entries-to-intclj

(reduce-entries-to-int this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToIntFunction basis - the identity (initial default value) for the reduction - int reducer - a commutative associative combining function - java.util.function.IntBinaryOperator

returns: the result of accumulating the given transformation of all entries - int

Returns the result of accumulating the given transformation
 of all entries using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToIntFunction`
basis - the identity (initial default value) for the reduction - `int`
reducer - a commutative associative combining function - `java.util.function.IntBinaryOperator`

returns: the result of accumulating the given transformation
 of all entries - `int`
raw docstring

reduce-entries-to-longclj

(reduce-entries-to-long this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all entries using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToLongFunction basis - the identity (initial default value) for the reduction - long reducer - a commutative associative combining function - java.util.function.LongBinaryOperator

returns: the result of accumulating the given transformation of all entries - long

Returns the result of accumulating the given transformation
 of all entries using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToLongFunction`
basis - the identity (initial default value) for the reduction - `long`
reducer - a commutative associative combining function - `java.util.function.LongBinaryOperator`

returns: the result of accumulating the given transformation
 of all entries - `long`
raw docstring

reduce-keysclj

(reduce-keys this parallelism-threshold reducer)
(reduce-keys this parallelism-threshold transformer reducer)

Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - java.util.function.Function reducer - a commutative associative combining function - java.util.function.BiFunction

returns: the result of accumulating the given transformation of all keys - <U> U

Returns the result of accumulating the given transformation
 of all keys using the given reducer to combine values, or
 null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - `java.util.function.Function`
reducer - a commutative associative combining function - `java.util.function.BiFunction`

returns: the result of accumulating the given transformation
 of all keys - `<U> U`
raw docstring

reduce-keys-to-doubleclj

(reduce-keys-to-double this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToDoubleFunction basis - the identity (initial default value) for the reduction - double reducer - a commutative associative combining function - java.util.function.DoubleBinaryOperator

returns: the result of accumulating the given transformation of all keys - double

Returns the result of accumulating the given transformation
 of all keys using the given reducer to combine values, and
 the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToDoubleFunction`
basis - the identity (initial default value) for the reduction - `double`
reducer - a commutative associative combining function - `java.util.function.DoubleBinaryOperator`

returns: the result of accumulating the given transformation
 of all keys - `double`
raw docstring

reduce-keys-to-intclj

(reduce-keys-to-int this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToIntFunction basis - the identity (initial default value) for the reduction - int reducer - a commutative associative combining function - java.util.function.IntBinaryOperator

returns: the result of accumulating the given transformation of all keys - int

Returns the result of accumulating the given transformation
 of all keys using the given reducer to combine values, and
 the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToIntFunction`
basis - the identity (initial default value) for the reduction - `int`
reducer - a commutative associative combining function - `java.util.function.IntBinaryOperator`

returns: the result of accumulating the given transformation
 of all keys - `int`
raw docstring

reduce-keys-to-longclj

(reduce-keys-to-long this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all keys using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToLongFunction basis - the identity (initial default value) for the reduction - long reducer - a commutative associative combining function - java.util.function.LongBinaryOperator

returns: the result of accumulating the given transformation of all keys - long

Returns the result of accumulating the given transformation
 of all keys using the given reducer to combine values, and
 the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToLongFunction`
basis - the identity (initial default value) for the reduction - `long`
reducer - a commutative associative combining function - `java.util.function.LongBinaryOperator`

returns: the result of accumulating the given transformation
 of all keys - `long`
raw docstring

reduce-to-doubleclj

(reduce-to-double this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToDoubleBiFunction basis - the identity (initial default value) for the reduction - double reducer - a commutative associative combining function - java.util.function.DoubleBinaryOperator

returns: the result of accumulating the given transformation of all (key, value) pairs - double

Returns the result of accumulating the given transformation
 of all (key, value) pairs using the given reducer to
 combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToDoubleBiFunction`
basis - the identity (initial default value) for the reduction - `double`
reducer - a commutative associative combining function - `java.util.function.DoubleBinaryOperator`

returns: the result of accumulating the given transformation
 of all (key, value) pairs - `double`
raw docstring

reduce-to-intclj

(reduce-to-int this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToIntBiFunction basis - the identity (initial default value) for the reduction - int reducer - a commutative associative combining function - java.util.function.IntBinaryOperator

returns: the result of accumulating the given transformation of all (key, value) pairs - int

Returns the result of accumulating the given transformation
 of all (key, value) pairs using the given reducer to
 combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToIntBiFunction`
basis - the identity (initial default value) for the reduction - `int`
reducer - a commutative associative combining function - `java.util.function.IntBinaryOperator`

returns: the result of accumulating the given transformation
 of all (key, value) pairs - `int`
raw docstring

reduce-to-longclj

(reduce-to-long this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all (key, value) pairs using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToLongBiFunction basis - the identity (initial default value) for the reduction - long reducer - a commutative associative combining function - java.util.function.LongBinaryOperator

returns: the result of accumulating the given transformation of all (key, value) pairs - long

Returns the result of accumulating the given transformation
 of all (key, value) pairs using the given reducer to
 combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToLongBiFunction`
basis - the identity (initial default value) for the reduction - `long`
reducer - a commutative associative combining function - `java.util.function.LongBinaryOperator`

returns: the result of accumulating the given transformation
 of all (key, value) pairs - `long`
raw docstring

reduce-valuesclj

(reduce-values this parallelism-threshold reducer)
(reduce-values this parallelism-threshold transformer reducer)

Returns the result of accumulating the given transformation of all values using the given reducer to combine values, or null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - java.util.function.Function reducer - a commutative associative combining function - java.util.function.BiFunction

returns: the result of accumulating the given transformation of all values - <U> U

Returns the result of accumulating the given transformation
 of all values using the given reducer to combine values, or
 null if none.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element, or null if there is no transformation (in which case it is not combined) - `java.util.function.Function`
reducer - a commutative associative combining function - `java.util.function.BiFunction`

returns: the result of accumulating the given transformation
 of all values - `<U> U`
raw docstring

reduce-values-to-doubleclj

(reduce-values-to-double this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToDoubleFunction basis - the identity (initial default value) for the reduction - double reducer - a commutative associative combining function - java.util.function.DoubleBinaryOperator

returns: the result of accumulating the given transformation of all values - double

Returns the result of accumulating the given transformation
 of all values using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToDoubleFunction`
basis - the identity (initial default value) for the reduction - `double`
reducer - a commutative associative combining function - `java.util.function.DoubleBinaryOperator`

returns: the result of accumulating the given transformation
 of all values - `double`
raw docstring

reduce-values-to-intclj

(reduce-values-to-int this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToIntFunction basis - the identity (initial default value) for the reduction - int reducer - a commutative associative combining function - java.util.function.IntBinaryOperator

returns: the result of accumulating the given transformation of all values - int

Returns the result of accumulating the given transformation
 of all values using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToIntFunction`
basis - the identity (initial default value) for the reduction - `int`
reducer - a commutative associative combining function - `java.util.function.IntBinaryOperator`

returns: the result of accumulating the given transformation
 of all values - `int`
raw docstring

reduce-values-to-longclj

(reduce-values-to-long this parallelism-threshold transformer basis reducer)

Returns the result of accumulating the given transformation of all values using the given reducer to combine values, and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long transformer - a function returning the transformation for an element - java.util.function.ToLongFunction basis - the identity (initial default value) for the reduction - long reducer - a commutative associative combining function - java.util.function.LongBinaryOperator

returns: the result of accumulating the given transformation of all values - long

Returns the result of accumulating the given transformation
 of all values using the given reducer to combine values,
 and the given basis as an identity value.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
transformer - a function returning the transformation for an element - `java.util.function.ToLongFunction`
basis - the identity (initial default value) for the reduction - `long`
reducer - a commutative associative combining function - `java.util.function.LongBinaryOperator`

returns: the result of accumulating the given transformation
 of all values - `long`
raw docstring

removeclj

(remove this key)
(remove this key value)

Removes the entry for a key only if currently mapped to a given value. This is equivalent to

if (map.containsKey(key) && Objects.equals(map.get(key), value)) { map.remove(key); return true; } else return false;

except that the action is performed atomically.

key - key with which the specified value is associated - java.lang.Object value - value expected to be associated with the specified key - java.lang.Object

returns: true if the value was removed - boolean

throws: java.lang.NullPointerException - if the specified key is null

Removes the entry for a key only if currently mapped to a given value.
 This is equivalent to


 if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
   map.remove(key);
   return true;
 } else
   return false;

 except that the action is performed atomically.

key - key with which the specified value is associated - `java.lang.Object`
value - value expected to be associated with the specified key - `java.lang.Object`

returns: true if the value was removed - `boolean`

throws: java.lang.NullPointerException - if the specified key is null
raw docstring

replaceclj

(replace this key value)
(replace this key old-value new-value)

Replaces the entry for a key only if currently mapped to a given value. This is equivalent to

if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) { map.put(key, newValue); return true; } else return false;

except that the action is performed atomically.

key - key with which the specified value is associated - K old-value - value expected to be associated with the specified key - V new-value - value to be associated with the specified key - V

returns: true if the value was replaced - boolean

throws: java.lang.NullPointerException - if any of the arguments are null

Replaces the entry for a key only if currently mapped to a given value.
 This is equivalent to


 if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) {
   map.put(key, newValue);
   return true;
 } else
   return false;

 except that the action is performed atomically.

key - key with which the specified value is associated - `K`
old-value - value expected to be associated with the specified key - `V`
new-value - value to be associated with the specified key - `V`

returns: true if the value was replaced - `boolean`

throws: java.lang.NullPointerException - if any of the arguments are null
raw docstring

replace-allclj

(replace-all this function)

Description copied from interface: ConcurrentMap

function - the function to apply to each entry - java.util.function.BiFunction

Description copied from interface: ConcurrentMap

function - the function to apply to each entry - `java.util.function.BiFunction`
raw docstring

(search this parallelism-threshold search-function)

Returns a non-null result from applying the given search function on each (key, value), or null if none. Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long search-function - a function returning a non-null result on success, else null - java.util.function.BiFunction

returns: a non-null result from applying the given search function on each (key, value), or null if none - <U> U

Returns a non-null result from applying the given search
 function on each (key, value), or null if none.  Upon
 success, further element processing is suppressed and the
 results of any other parallel invocations of the search
 function are ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
search-function - a function returning a non-null result on success, else null - `java.util.function.BiFunction`

returns: a non-null result from applying the given search
 function on each (key, value), or null if none - `<U> U`
raw docstring

search-entriesclj

(search-entries this parallelism-threshold search-function)

Returns a non-null result from applying the given search function on each entry, or null if none. Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long search-function - a function returning a non-null result on success, else null - java.util.function.Function

returns: a non-null result from applying the given search function on each entry, or null if none - <U> U

Returns a non-null result from applying the given search
 function on each entry, or null if none.  Upon success,
 further element processing is suppressed and the results of
 any other parallel invocations of the search function are
 ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
search-function - a function returning a non-null result on success, else null - `java.util.function.Function`

returns: a non-null result from applying the given search
 function on each entry, or null if none - `<U> U`
raw docstring

search-keysclj

(search-keys this parallelism-threshold search-function)

Returns a non-null result from applying the given search function on each key, or null if none. Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long search-function - a function returning a non-null result on success, else null - java.util.function.Function

returns: a non-null result from applying the given search function on each key, or null if none - <U> U

Returns a non-null result from applying the given search
 function on each key, or null if none. Upon success,
 further element processing is suppressed and the results of
 any other parallel invocations of the search function are
 ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
search-function - a function returning a non-null result on success, else null - `java.util.function.Function`

returns: a non-null result from applying the given search
 function on each key, or null if none - `<U> U`
raw docstring

search-valuesclj

(search-values this parallelism-threshold search-function)

Returns a non-null result from applying the given search function on each value, or null if none. Upon success, further element processing is suppressed and the results of any other parallel invocations of the search function are ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - long search-function - a function returning a non-null result on success, else null - java.util.function.Function

returns: a non-null result from applying the given search function on each value, or null if none - <U> U

Returns a non-null result from applying the given search
 function on each value, or null if none.  Upon success,
 further element processing is suppressed and the results of
 any other parallel invocations of the search function are
 ignored.

parallelism-threshold - the (estimated) number of elements needed for this operation to be executed in parallel - `long`
search-function - a function returning a non-null result on success, else null - `java.util.function.Function`

returns: a non-null result from applying the given search
 function on each value, or null if none - `<U> U`
raw docstring

sizeclj

(size this)

Returns the number of key-value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

returns: the number of key-value mappings in this map - int

Returns the number of key-value mappings in this map.  If the
 map contains more than Integer.MAX_VALUE elements, returns
 Integer.MAX_VALUE.

returns: the number of key-value mappings in this map - `int`
raw docstring

to-stringclj

(to-string this)

Returns a string representation of this map. The string representation consists of a list of key-value mappings (in no particular order) enclosed in braces ("{}"). Adjacent mappings are separated by the characters ", " (comma and space). Each key-value mapping is rendered as the key followed by an equals sign ("=") followed by the associated value.

returns: a string representation of this map - java.lang.String

Returns a string representation of this map.  The string
 representation consists of a list of key-value mappings (in no
 particular order) enclosed in braces ("{}").  Adjacent
 mappings are separated by the characters ", " (comma
 and space).  Each key-value mapping is rendered as the key
 followed by an equals sign ("=") followed by the
 associated value.

returns: a string representation of this map - `java.lang.String`
raw docstring

valuesclj

(values this)

Returns a Collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. The collection supports element removal, which removes the corresponding mapping from this map, via the Iterator.remove, Collection.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

The view's iterators and spliterators are weakly consistent.

The view's spliterator reports Spliterator.CONCURRENT and Spliterator.NONNULL.

returns: the collection view - java.util.Collection<V>

Returns a Collection view of the values contained in this map.
 The collection is backed by the map, so changes to the map are
 reflected in the collection, and vice-versa.  The collection
 supports element removal, which removes the corresponding
 mapping from this map, via the Iterator.remove,
 Collection.remove, removeAll,
 retainAll, and clear operations.  It does not
 support the add or addAll operations.

 The view's iterators and spliterators are
 weakly consistent.

 The view's spliterator reports Spliterator.CONCURRENT
 and Spliterator.NONNULL.

returns: the collection view - `java.util.Collection<V>`
raw docstring

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