ConcurrentLongKeyHashMap

java.lang.Object
- fabric.common.util.AbstractLongKeyMap<V>
- - fabric.common.util.ConcurrentLongKeyHashMap<V>

Type Parameters:

V - the type of mapped values

All Implemented Interfaces:

ConcurrentLongKeyMap<V>, LongKeyMap<V>, java.io.Serializable
```
public class ConcurrentLongKeyHashMap<V>
extends AbstractLongKeyMap<V>
implements ConcurrentLongKeyMap<V>, java.io.Serializable
```
A hash table supporting full concurrency of retrievals and adjustable 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. For aggregate operations such as putAll and clear, concurrent retrievals may reflect insertion or removal of only some entries. Similarly, Iterators 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.
The allowed concurrency among update operations is guided by the optional concurrencyLevel constructor argument (default 16), which is used as a hint for internal sizing. The table is internally partitioned to try to permit the indicated number of concurrent updates without contention. Because placement in hash tables is essentially random, the actual concurrency will vary. Ideally, you should choose a value to accommodate as many threads as will ever concurrently modify the table. Using a significantly higher value than you need can waste space and time, and a significantly lower value can lead to thread contention. But overestimates and underestimates within an order of magnitude do not usually have much noticeable impact. A value of one is appropriate when it is known that only one thread will modify and all others will only read. Also, resizing this or any other kind of hash table is a relatively slow operation, so, when possible, it is a good idea to provide estimates of expected table sizes in constructors.
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.
This class is a member of the Java Collections Framework.

Since:

1.5

Author:

Doug Lea

See Also:

Serialized Form

Nested Class Summary
- Nested classes/interfaces inherited from class fabric.common.util.AbstractLongKeyMap
  AbstractLongKeyMap.SimpleEntry<V>, AbstractLongKeyMap.SimpleImmutableEntry<V>
- Nested classes/interfaces inherited from interface fabric.common.util.LongKeyMap
  LongKeyMap.Entry<V>

Constructor Summary

Constructors
Constructor and Description
`ConcurrentLongKeyHashMap()` Creates a new, empty map with a default initial capacity (16), load factor (0.75) and concurrencyLevel (16).
`ConcurrentLongKeyHashMap(int initialCapacity)` Creates a new, empty map with the specified initial capacity, and with default load factor (0.75) and concurrencyLevel (16).
`ConcurrentLongKeyHashMap(int initialCapacity, float loadFactor)` Creates a new, empty map with the specified initial capacity and load factor and with the default concurrencyLevel (16).
`ConcurrentLongKeyHashMap(int initialCapacity, float loadFactor, int concurrencyLevel)` Creates a new, empty map with the specified initial capacity, load factor and concurrency level.
`ConcurrentLongKeyHashMap(LongKeyMap<? extends V> m)` Creates a new map with the same mappings as the given map.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clear()` Removes all of the mappings from this map.
`boolean`	`contains(java.lang.Object value)` Legacy method testing if some key maps into the specified value in this table.
`boolean`	`containsKey(long key)` Tests if the specified object is a key in this table.
`boolean`	`containsValue(java.lang.Object value)` Returns `true` if this map maps one or more keys to the specified value.
`java.util.Enumeration<V>`	`elements()` Returns an enumeration of the values in this table.
`java.util.Set<LongKeyMap.Entry<V>>`	`entrySet()` Returns a `Set` view of the mappings contained in this map.
`V`	`get(long key)` Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
`boolean`	`isEmpty()` Returns `true` if this map contains no key-value mappings.
`LongSet`	`keySet()` Returns a `Set` view of the keys contained in this map.
`V`	`put(long key, V value)` Maps the specified key to the specified value in this table.
`<T extends V> void`	`putAll(LongKeyMap<T> m)` Copies all of the mappings from the specified map to this one.
`V`	`putIfAbsent(long key, V value)` If the specified key is not already associated with a value, associate it with the given value.
`V`	`remove(long key)` Removes the key (and its corresponding value) from this map.
`boolean`	`remove(long key, java.lang.Object value)` Removes the entry for a key only if currently mapped to a given value.
`V`	`replace(long key, V value)` Replaces the entry for a key only if currently mapped to some value.
`boolean`	`replace(long key, V oldValue, V newValue)` Replaces the entry for a key only if currently mapped to a given value.
`int`	`size()` Returns the number of key-value mappings in this map.
`java.util.Collection<V>`	`values()` Returns a `Collection` view of the values contained in this map.

Methods inherited from class fabric.common.util.AbstractLongKeyMap
clone, equals, hashCode, toString

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface fabric.common.util.LongKeyMap
equals, hashCode

- Constructor Detail
  - ConcurrentLongKeyHashMap
```
public ConcurrentLongKeyHashMap(int initialCapacity,
                                float loadFactor,
                                int concurrencyLevel)
```
    Creates a new, empty map with the specified initial capacity, load factor and concurrency level.
    
    Parameters:
    
    initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements.
    
    loadFactor - the load factor threshold, used to control resizing. Resizing may be performed when the average number of elements per bin exceeds this threshold.
    
    concurrencyLevel - the estimated number of concurrently updating threads. The implementation performs internal sizing to try to accommodate this many threads.
    
    Throws:
    
    java.lang.IllegalArgumentException - if the initial capacity is negative or the load factor or concurrencyLevel are nonpositive.
  - ConcurrentLongKeyHashMap
```
public ConcurrentLongKeyHashMap(int initialCapacity,
                                float loadFactor)
```
    Creates a new, empty map with the specified initial capacity and load factor and with the default concurrencyLevel (16).
    
    Parameters:
    
    initialCapacity - The implementation performs internal sizing to accommodate this many elements.
    
    loadFactor - the load factor threshold, used to control resizing. Resizing may be performed when the average number of elements per bin exceeds this threshold.
    
    Throws:
    
    java.lang.IllegalArgumentException - if the initial capacity of elements is negative or the load factor is nonpositive
    
    Since:
    
    1.6
  - ConcurrentLongKeyHashMap
```
public ConcurrentLongKeyHashMap(int initialCapacity)
```
    Creates a new, empty map with the specified initial capacity, and with default load factor (0.75) and concurrencyLevel (16).
    
    Parameters:
    
    initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements.
    
    Throws:
    
    java.lang.IllegalArgumentException - if the initial capacity of elements is negative.
  - ConcurrentLongKeyHashMap
```
public ConcurrentLongKeyHashMap()
```
    Creates a new, empty map with a default initial capacity (16), load factor (0.75) and concurrencyLevel (16).
  - ConcurrentLongKeyHashMap
```
public ConcurrentLongKeyHashMap(LongKeyMap<? extends V> m)
```
    Creates a new map with the same mappings as the given map. The map is created with a capacity of 1.5 times the number of mappings in the given map or 16 (whichever is greater), and a default load factor (0.75) and concurrencyLevel (16).
    
    Parameters:
    
    m - the map
- Method Detail
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this map contains no key-value mappings.
    
    Specified by:
    
    isEmpty in interface LongKeyMap<V>
    
    Overrides:
    
    isEmpty in class AbstractLongKeyMap<V>
    
    Returns:
    
    true if this map contains no key-value mappings
    
    See Also:
    
    AbstractLongKeyMap.size()
  - size
```
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.
    
    Specified by:
    
    size in interface LongKeyMap<V>
    
    Overrides:
    
    size in class AbstractLongKeyMap<V>
    
    Returns:
    
    the number of key-value mappings in this map
    
    See Also:
    
    Set.size()
  - get
```
public V get(long 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.)
    
    Specified by:
    
    get in interface LongKeyMap<V>
    
    Overrides:
    
    get in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key to look up
    
    Returns:
    
    the value associated with the key, or null if key not in map
    
    Throws:
    
    java.lang.NullPointerException - if the specified key is null
    
    See Also:
    
    AbstractLongKeyMap.containsKey(long)
  - containsKey
```
public boolean containsKey(long key)
```
    Tests if the specified object is a key in this table.
    
    Specified by:
    
    containsKey in interface LongKeyMap<V>
    
    Overrides:
    
    containsKey in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - possible key
    
    Returns:
    
    true if and only if the specified object is a key in this table, as determined by the equals method; false otherwise.
    
    Throws:
    
    java.lang.NullPointerException - if the specified key is null
    
    See Also:
    
    AbstractLongKeyMap.containsValue(Object)
  - containsValue
```
public boolean containsValue(java.lang.Object value)
```
    Returns true if this map maps one or more keys to the specified value. Note: This method requires a full internal traversal of the hash table, and so is much slower than method containsKey.
    
    Specified by:
    
    containsValue in interface LongKeyMap<V>
    
    Overrides:
    
    containsValue in class AbstractLongKeyMap<V>
    
    Parameters:
    
    value - value whose presence in this map is to be tested
    
    Returns:
    
    true if this map maps one or more keys to the specified value
    
    Throws:
    
    java.lang.NullPointerException - if the specified value is null
    
    See Also:
    
    AbstractLongKeyMap.containsKey(long)
  - contains
```
public boolean contains(java.lang.Object value)
```
    Legacy method testing if some key maps into the specified value in this table. This method is identical in functionality to containsValue(java.lang.Object), and exists solely to ensure full compatibility with class Hashtable, which supported this method prior to introduction of the Java Collections framework.
    
    Parameters:
    
    value - a value to search for
    
    Returns:
    
    true if and only if some key maps to the value argument in this table as determined by the equals method; false otherwise
    
    Throws:
    
    java.lang.NullPointerException - if the specified value is null
  - put
```
public V put(long key,
             V 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.
    
    Specified by:
    
    put in interface LongKeyMap<V>
    
    Overrides:
    
    put in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the specified key
    
    Returns:
    
    the previous value associated with key, or null if there was no mapping for key
    
    Throws:
    
    java.lang.NullPointerException - if the specified key or value is null
    
    See Also:
    
    AbstractLongKeyMap.containsKey(long)
  - putIfAbsent
```
public V putIfAbsent(long key,
                     V 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.
    Specified by:
    
    putIfAbsent in interface ConcurrentLongKeyMap<V>
    
    Parameters:
    
    key - key with which the specified value is to be associated
    
    value - value to be associated with the specified key
    
    Returns:
    
    the previous value associated with the specified key, or null if there was no mapping for the key
    
    Throws:
    
    java.lang.NullPointerException - if the specified key or value is null
  - putAll
```
public <T extends V> void putAll(LongKeyMap<T> 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.
    
    Specified by:
    
    putAll in interface LongKeyMap<V>
    
    Overrides:
    
    putAll in class AbstractLongKeyMap<V>
    
    Parameters:
    
    m - mappings to be stored in this map
    
    See Also:
    
    AbstractLongKeyMap.put(long, Object)
  - remove
```
public V remove(long key)
```
    Removes the key (and its corresponding value) from this map. This method does nothing if the key is not in the map.
    
    Specified by:
    
    remove in interface LongKeyMap<V>
    
    Overrides:
    
    remove in class AbstractLongKeyMap<V>
    
    Parameters:
    
    key - the key that needs to be removed
    
    Returns:
    
    the previous value associated with key, or null if there was no mapping for key
    
    Throws:
    
    java.lang.NullPointerException - if the specified key is null
    
    See Also:
    
    Iterator.remove()
  - remove
```
public boolean remove(long key,
                      java.lang.Object value)
```
    Removes the entry for a key only if currently mapped to a given value. This is equivalent to
```
   if (map.containsKey(key) && map.get(key).equals(value)) {
       map.remove(key);
       return true;
   } else return false;
```
    except that the action is performed atomically.
    Specified by:
    
    remove in interface ConcurrentLongKeyMap<V>
    
    Parameters:
    
    key - key with which the specified value is associated
    
    value - value expected to be associated with the specified key
    
    Returns:
    
    true if the value was removed
    
    Throws:
    
    java.lang.NullPointerException - if the specified key is null
  - replace
```
public boolean replace(long key,
                       V oldValue,
                       V newValue)
```
    Replaces the entry for a key only if currently mapped to a given value. This is equivalent to
```
   if (map.containsKey(key) && map.get(key).equals(oldValue)) {
       map.put(key, newValue);
       return true;
   } else return false;
```
    except that the action is performed atomically.
    Specified by:
    
    replace in interface ConcurrentLongKeyMap<V>
    
    Parameters:
    
    key - key with which the specified value is associated
    
    oldValue - value expected to be associated with the specified key
    
    newValue - value to be associated with the specified key
    
    Returns:
    
    true if the value was replaced
    
    Throws:
    
    java.lang.NullPointerException - if any of the arguments are null
  - replace
```
public V replace(long key,
                 V value)
```
    Replaces the entry for a key only if currently mapped to some value. This is equivalent to
```
   if (map.containsKey(key)) {
       return map.put(key, value);
   } else return null;
```
    except that the action is performed atomically.
    Specified by:
    
    replace in interface ConcurrentLongKeyMap<V>
    
    Parameters:
    
    key - key with which the specified value is associated
    
    value - value to be associated with the specified key
    
    Returns:
    
    the previous value associated with the specified key, or null if there was no mapping for the key
    
    Throws:
    
    java.lang.NullPointerException - if the specified key or value is null
  - clear
```
public void clear()
```
    Removes all of the mappings from this map.
    
    Specified by:
    
    clear in interface LongKeyMap<V>
    
    Overrides:
    
    clear in class AbstractLongKeyMap<V>
    
    See Also:
    
    LongSet.clear()
  - keySet
```
public LongSet keySet()
```
    Returns a Set view of the keys 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 this map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.
    The view's iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
    
    Specified by:
    
    keySet in interface LongKeyMap<V>
    
    Overrides:
    
    keySet in class AbstractLongKeyMap<V>
    
    Returns:
    
    a Set view of the keys
    
    See Also:
    
    LongSet.iterator(), AbstractLongKeyMap.size(), AbstractLongKeyMap.containsKey(long), AbstractLongKeyMap.values()
  - values
```
public java.util.Collection<V> values()
```
    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 iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
    
    Specified by:
    
    values in interface LongKeyMap<V>
    
    Overrides:
    
    values in class AbstractLongKeyMap<V>
    
    Returns:
    
    a Collection view of the values
    
    See Also:
    
    LongCollection.iterator(), AbstractLongKeyMap.size(), AbstractLongKeyMap.containsValue(Object), AbstractLongKeyMap.keySet()
  - entrySet
```
public java.util.Set<LongKeyMap.Entry<V>> entrySet()
```
    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. It does not support the add or addAll operations.
    The view's iterator is a "weakly consistent" iterator that will never throw ConcurrentModificationException, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
    
    Specified by:
    
    entrySet in interface LongKeyMap<V>
    
    Specified by:
    
    entrySet in class AbstractLongKeyMap<V>
    
    Returns:
    
    the entry set
    
    See Also:
    
    LongKeyMap.Entry
  - elements
```
public java.util.Enumeration<V> elements()
```
    Returns an enumeration of the values in this table.
    
    Returns:
    
    an enumeration of the values in this table
    
    See Also:
    
    values()

Class ConcurrentLongKeyHashMap<V>

Nested Class Summary

Nested classes/interfaces inherited from class fabric.common.util.AbstractLongKeyMap

Nested classes/interfaces inherited from interface fabric.common.util.LongKeyMap

Constructor Summary

Method Summary

Methods inherited from class fabric.common.util.AbstractLongKeyMap

Methods inherited from class java.lang.Object

Methods inherited from interface fabric.common.util.LongKeyMap

Constructor Detail

ConcurrentLongKeyHashMap

ConcurrentLongKeyHashMap

ConcurrentLongKeyHashMap

ConcurrentLongKeyHashMap

ConcurrentLongKeyHashMap

Method Detail

isEmpty

size

get

containsKey

containsValue

contains

put

putIfAbsent

putAll

remove

remove

replace

replace

clear

keySet

values

entrySet

elements