it.unimi.dsi.fastutil.ints
Class Int2ObjectOpenHashMap<V>

java.lang.Object
  extended by it.unimi.dsi.fastutil.ints.AbstractInt2ObjectFunction<V>
      extended by it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap<V>
          extended by it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap<V>
All Implemented Interfaces:
Function<java.lang.Integer,V>, Hash, Int2ObjectFunction<V>, Int2ObjectMap<V>, java.io.Serializable, java.lang.Cloneable, java.util.Map<java.lang.Integer,V>

public class Int2ObjectOpenHashMap<V>
extends AbstractInt2ObjectMap<V>
implements java.io.Serializable, java.lang.Cloneable, Hash

A type-specific hash map with a fast, small-footprint implementation.

Instances of this class use a hash table to represent a map. The table is enlarged as needed when new entries are created, but it is never made smaller (even on a clear()). A family of trimming methods lets you control the size of the table; this is particularly useful if you reuse instances of this class.

The enlargement speed is controlled by the growth factor, a positive number. If the growth factor is p, then the table is enlarged each time roughly by a factor 2p/16. By default, p is Hash.DEFAULT_GROWTH_FACTOR, which means that the table is doubled at each enlargement, but one can easily set more or less aggressive policies by calling growthFactor(int) (note that the growth factor is not serialized: deserialized tables gets the default growth factor).

See Also:
Hash, HashCommon, Serialized Form

Nested Class Summary
 
Nested classes/interfaces inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap
AbstractInt2ObjectMap.BasicEntry<V>
 
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.Hash
Hash.Strategy<K>
 
Nested classes/interfaces inherited from interface it.unimi.dsi.fastutil.ints.Int2ObjectMap
Int2ObjectMap.Entry<V>, Int2ObjectMap.FastEntrySet<V>
 
Field Summary
static long serialVersionUID
           
 
Fields inherited from interface it.unimi.dsi.fastutil.Hash
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FAST_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED, VERY_FAST_LOAD_FACTOR
 
Constructor Summary
Int2ObjectOpenHashMap()
          Creates a new hash map with Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.
Int2ObjectOpenHashMap(int n)
          Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.
Int2ObjectOpenHashMap(int[] k, V[] v)
          Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.
Int2ObjectOpenHashMap(int[] k, V[] v, float f)
          Creates a new hash map using the elements of two parallel arrays.
Int2ObjectOpenHashMap(Int2ObjectMap<V> m)
          Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.
Int2ObjectOpenHashMap(Int2ObjectMap<V> m, float f)
          Creates a new hash map copying a given type-specific one.
Int2ObjectOpenHashMap(int n, float f)
          Creates a new hash map.
Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m)
          Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.
Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m, float f)
          Creates a new hash map copying a given one.
 
Method Summary
 void clear()
          Removes all associations from this function (optional operation).
 java.lang.Object clone()
          Returns a deep copy of this map.
 boolean containsKey(int k)
          Checks whether the given value is contained in AbstractInt2ObjectMap.keySet().
 boolean containsValue(java.lang.Object v)
          Checks whether the given value is contained in AbstractInt2ObjectMap.values().
 V get(int k)
          Returns the value to which the given key is mapped.
 V get(java.lang.Integer ok)
           
 int growthFactor()
          Gets the growth factor.
 void growthFactor(int growthFactor)
          Sets the growth factor.
 int hashCode()
          Returns a hash code for this map.
 Int2ObjectMap.FastEntrySet<V> int2ObjectEntrySet()
          Returns a type-specific set view of the mappings contained in this map.
 boolean isEmpty()
           
 IntSet keySet()
          Returns a type-specific-set view of the keys of this map.
 V put(java.lang.Integer ok, V ov)
          Delegates to the corresponding type-specific method, taking care of returning null on a missing key.
 V put(int k, V v)
          Adds a pair to the map.
 boolean rehash()
          Rehashes this map without changing the table size.
 V remove(int k)
          Removes the mapping with the given key.
 V remove(java.lang.Object ok)
          Delegates to the corresponding type-specific method, taking care of returning null on a missing key.
 int size()
          Returns the intended number of keys in this function, or -1 if no such number exists.
 boolean trim()
          Rehashes the map, making the table as small as possible.
 boolean trim(int n)
          Rehashes this map if the table is too large.
 ObjectCollection<V> values()
          Returns a type-specific-set view of the values of this map.
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectMap
entrySet, equals, putAll, toString
 
Methods inherited from class it.unimi.dsi.fastutil.ints.AbstractInt2ObjectFunction
containsKey, defaultReturnValue, defaultReturnValue, get
 
Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface it.unimi.dsi.fastutil.ints.Int2ObjectFunction
defaultReturnValue, defaultReturnValue
 
Methods inherited from interface it.unimi.dsi.fastutil.Function
containsKey, get
 
Methods inherited from interface java.util.Map
containsKey, get
 

Field Detail

serialVersionUID

public static final long serialVersionUID
See Also:
Constant Field Values
Constructor Detail

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int n,
                             float f)
Creates a new hash map. The actual table size is the least available prime greater than n/f.

Parameters:
n - the expected number of elements in the hash map.
f - the load factor.
See Also:
Hash.PRIMES

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int n)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor.

Parameters:
n - the expected number of elements in the hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap()
Creates a new hash map with Hash.DEFAULT_INITIAL_SIZE entries and Hash.DEFAULT_LOAD_FACTOR as load factor.


Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m,
                             float f)
Creates a new hash map copying a given one.

Parameters:
m - a Map to be copied into the new hash map.
f - the load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(java.util.Map<? extends java.lang.Integer,? extends V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one.

Parameters:
m - a Map to be copied into the new hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(Int2ObjectMap<V> m,
                             float f)
Creates a new hash map copying a given type-specific one.

Parameters:
m - a type-specific map to be copied into the new hash map.
f - the load factor.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(Int2ObjectMap<V> m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one.

Parameters:
m - a type-specific map to be copied into the new hash map.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int[] k,
                             V[] v,
                             float f)
Creates a new hash map using the elements of two parallel arrays.

Parameters:
k - the array of keys of the new hash map.
v - the array of corresponding values in the new hash map.
f - the load factor.
Throws:
java.lang.IllegalArgumentException - if k and v have different lengths.

Int2ObjectOpenHashMap

public Int2ObjectOpenHashMap(int[] k,
                             V[] v)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor using the elements of two parallel arrays.

Parameters:
k - the array of keys of the new hash map.
v - the array of corresponding values in the new hash map.
Throws:
java.lang.IllegalArgumentException - if k and v have different lengths.
Method Detail

growthFactor

public void growthFactor(int growthFactor)
Sets the growth factor. Subsequent enlargements will increase the table size roughly by a multiplicative factor of 2p/16.

Parameters:
growthFactor - the new growth factor; it must be positive.

growthFactor

public int growthFactor()
Gets the growth factor.

Returns:
the growth factor of this set.
See Also:
growthFactor(int)

put

public V put(int k,
             V v)
Description copied from interface: Int2ObjectFunction
Adds a pair to the map.

Specified by:
put in interface Int2ObjectFunction<V>
Overrides:
put in class AbstractInt2ObjectFunction<V>
Parameters:
k - the key.
v - the value.
Returns:
the old value, or the default return value if no value was present for the given key.
See Also:
Function.put(Object,Object)

put

public V put(java.lang.Integer ok,
             V ov)
Description copied from class: AbstractInt2ObjectFunction
Delegates to the corresponding type-specific method, taking care of returning null on a missing key.

This method must check whether the provided key is in the map using containsKey(). Thus, it probes the map twice. Implementors of subclasses should override it with a more efficient method.

Specified by:
put in interface Function<java.lang.Integer,V>
Specified by:
put in interface java.util.Map<java.lang.Integer,V>
Overrides:
put in class AbstractInt2ObjectFunction<V>
Parameters:
ok - the key.
ov - the value.
Returns:
the old value, or null if no value was present for the given key.
See Also:
Map.put(Object,Object)

containsValue

public boolean containsValue(java.lang.Object v)
Description copied from class: AbstractInt2ObjectMap
Checks whether the given value is contained in AbstractInt2ObjectMap.values().

Specified by:
containsValue in interface java.util.Map<java.lang.Integer,V>
Overrides:
containsValue in class AbstractInt2ObjectMap<V>

clear

public void clear()
Description copied from interface: Function
Removes all associations from this function (optional operation).

Specified by:
clear in interface Function<java.lang.Integer,V>
Specified by:
clear in interface java.util.Map<java.lang.Integer,V>
Overrides:
clear in class AbstractInt2ObjectFunction<V>
See Also:
Map.clear()

containsKey

public boolean containsKey(int k)
Description copied from class: AbstractInt2ObjectMap
Checks whether the given value is contained in AbstractInt2ObjectMap.keySet().

Specified by:
containsKey in interface Int2ObjectFunction<V>
Overrides:
containsKey in class AbstractInt2ObjectMap<V>
See Also:
Function.containsKey(Object)

size

public int size()
Description copied from interface: Function
Returns the intended number of keys in this function, or -1 if no such number exists.

Most function implementations will have some knowledge of the intended number of keys in their domain. In some cases, however, this might not be possible.

Specified by:
size in interface Function<java.lang.Integer,V>
Specified by:
size in interface java.util.Map<java.lang.Integer,V>
Returns:
the intended number of keys in this function, or -1 if that number is not available.

isEmpty

public boolean isEmpty()
Specified by:
isEmpty in interface java.util.Map<java.lang.Integer,V>
Overrides:
isEmpty in class AbstractInt2ObjectMap<V>

get

public V get(int k)
Description copied from interface: Int2ObjectFunction
Returns the value to which the given key is mapped.

Specified by:
get in interface Int2ObjectFunction<V>
Parameters:
k - the key.
Returns:
the corresponding value, or the default return value if no value was present for the given key.
See Also:
Function.get(Object)

remove

public V remove(int k)
Description copied from interface: Int2ObjectFunction
Removes the mapping with the given key.

Specified by:
remove in interface Int2ObjectFunction<V>
Overrides:
remove in class AbstractInt2ObjectFunction<V>
Returns:
the old value, or the default return value if no value was present for the given key.
See Also:
Function.remove(Object)

get

public V get(java.lang.Integer ok)

remove

public V remove(java.lang.Object ok)
Description copied from class: AbstractInt2ObjectFunction
Delegates to the corresponding type-specific method, taking care of returning null on a missing key.

This method must check whether the provided key is in the map using containsKey(). Thus, it probes the map twice. Implementors of subclasses should override it with a more efficient method.

Specified by:
remove in interface Function<java.lang.Integer,V>
Specified by:
remove in interface java.util.Map<java.lang.Integer,V>
Overrides:
remove in class AbstractInt2ObjectFunction<V>
Returns:
the old value, or null if no value was present for the given key.
See Also:
Map.remove(Object)

int2ObjectEntrySet

public Int2ObjectMap.FastEntrySet<V> int2ObjectEntrySet()
Description copied from interface: Int2ObjectMap
Returns a type-specific set view of the mappings contained in this map.

This method is necessary because there is no inheritance along type parameters: it is thus impossible to strengthen Int2ObjectMap.entrySet() so that it returns an ObjectSet of objects of type Int2ObjectMap.Entry (the latter makes it possible to access keys and values with type-specific methods).

Specified by:
int2ObjectEntrySet in interface Int2ObjectMap<V>
Returns:
a type-specific set view of the mappings contained in this map.
See Also:
Int2ObjectMap.entrySet()

keySet

public IntSet keySet()
Description copied from class: AbstractInt2ObjectMap
Returns a type-specific-set view of the keys of this map.

The view is backed by the set returned by AbstractInt2ObjectMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:
keySet in interface Int2ObjectMap<V>
Specified by:
keySet in interface java.util.Map<java.lang.Integer,V>
Overrides:
keySet in class AbstractInt2ObjectMap<V>
Returns:
a set view of the keys of this map; it may be safely cast to a type-specific interface.
See Also:
Map.keySet()

values

public ObjectCollection<V> values()
Description copied from class: AbstractInt2ObjectMap
Returns a type-specific-set view of the values of this map.

The view is backed by the set returned by AbstractInt2ObjectMap.entrySet(). Note that no attempt is made at caching the result of this method, as this would require adding some attributes that lightweight implementations would not need. Subclasses may easily override this policy by calling this method and caching the result, but implementors are encouraged to write more efficient ad-hoc implementations.

Specified by:
values in interface Int2ObjectMap<V>
Specified by:
values in interface java.util.Map<java.lang.Integer,V>
Overrides:
values in class AbstractInt2ObjectMap<V>
Returns:
a set view of the values of this map; it may be safely cast to a type-specific interface.
See Also:
Map.values()

rehash

public boolean rehash()
Rehashes this map without changing the table size.

This method should be called when the map underwent numerous deletions and insertions. In this case, free entries become rare, and unsuccessful searches require probing all entries. For reasonable load factors this method is linear in the number of entries. You will need as much additional free memory as that occupied by the table.

If you need to reduce the table siza to fit exactly this map, you must use trim().

Returns:
true if there was enough memory to rehash the map, false otherwise.
See Also:
trim()

trim

public boolean trim()
Rehashes the map, making the table as small as possible.

This method rehashes to the smallest size satisfying the load factor. It can be used when the map will not be changed anymore, so to optimize access speed (by collecting deleted entries) and size.

If the table size is already the minimum possible, this method does nothing. If you want to guarantee rehashing, use rehash().

Returns:
true if there was enough memory to trim the map.
See Also:
trim(int), rehash()

trim

public boolean trim(int n)
Rehashes this map if the table is too large.

Let N be the smallest table size that can hold max(n,size()) entries, still satisfying the load factor. If the current table size is smaller than or equal to N, this method does nothing. Otherwise, it rehashes this map in a table of size N.

This method is useful when reusing maps. Clearing a map leaves the table size untouched. If you are reusing a map many times, you can call this method with a typical size to avoid keeping around a very large table just because of a few large transient maps.

Parameters:
n - the threshold for the trimming.
Returns:
true if there was enough memory to trim the map.
See Also:
trim(), rehash()

clone

public java.lang.Object clone()
Returns a deep copy of this map.

This method performs a deep copy of this hash map; the data stored in the map, however, is not cloned. Note that this makes a difference only for object keys.

Overrides:
clone in class java.lang.Object
Returns:
a deep copy of this map.

hashCode

public int hashCode()
Returns a hash code for this map. This method overrides the generic method provided by the superclass. Since equals() is not overriden, it is important that the value returned by this method is the same value as the one returned by the overriden method.

Specified by:
hashCode in interface java.util.Map<java.lang.Integer,V>
Overrides:
hashCode in class AbstractInt2ObjectMap<V>
Returns:
a hash code for this map.