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java.lang.Objectit.unimi.dsi.fastutil.bytes.AbstractByte2ByteMap
it.unimi.dsi.fastutil.bytes.AbstractByte2ByteSortedMap
it.unimi.dsi.fastutil.bytes.Byte2ByteLinkedOpenHashMap
A type-specific linked hash map with 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).
This class implements the interface of a sorted map, so to allow easy
access of the iteration order: for instance, you can get the first key
in iteration order with AbstractByte2ByteSortedMap.firstKey()
without having to create an
iterator; however, this class partially violates the SortedMap
contract because all submap methods throw an exception and comparator()
returns always null
.
The iterators provided by the views of this class using are type-specific
list iterators. However, creation of an
iterator using a starting point is going to be very expensive, as the chosen
starting point must be linearly searched for, unless it is AbstractByte2ByteSortedMap.lastKey()
,
in which case the iterator is created in constant time.
Note that deletions in a linked table require scanning the list until the element to be removed is found. The only exceptions are the first element, the last element, and deletions performed using an iterator.
Hash
,
HashCommon
,
Serialized FormNested Class Summary |
Nested classes inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ByteMap |
AbstractByte2ByteMap.BasicEntry |
Nested classes inherited from class it.unimi.dsi.fastutil.Hash |
Hash.Strategy |
Nested classes inherited from class it.unimi.dsi.fastutil.bytes.Byte2ByteMap |
Byte2ByteMap.Entry |
Field Summary | |
static long |
serialVersionUID
|
Fields inherited from interface it.unimi.dsi.fastutil.Hash |
DEFAULT_GROWTH_FACTOR, DEFAULT_INITIAL_SIZE, DEFAULT_LOAD_FACTOR, FREE, OCCUPIED, PRIMES, REMOVED |
Constructor Summary | |
Byte2ByteLinkedOpenHashMap()
Creates a new hash map with Hash.DEFAULT_INITIAL_SIZE entries
and Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Byte2ByteLinkedOpenHashMap(Byte2ByteMap m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given type-specific one. |
|
Byte2ByteLinkedOpenHashMap(Byte2ByteMap m,
float f)
Creates a new hash map copying a given type-specific one. |
|
Byte2ByteLinkedOpenHashMap(int n)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor. |
|
Byte2ByteLinkedOpenHashMap(int n,
float f)
Creates a new hash map. |
|
Byte2ByteLinkedOpenHashMap(Map m)
Creates a new hash map with Hash.DEFAULT_LOAD_FACTOR as load factor copying a given one. |
|
Byte2ByteLinkedOpenHashMap(Map m,
float f)
Creates a new hash map copying a given one. |
Method Summary | |
void |
clear()
|
Object |
clone()
Returns a deep copy of this map. |
Comparator |
comparator()
|
boolean |
containsKey(byte k)
Checks whether the given value is contained in keySet() . |
boolean |
containsValue(byte v)
Checks whether the given value is contained in values() . |
Set |
entrySet()
|
byte |
firstByteKey()
Returns the first key of this map in iteration order. |
byte |
get(byte k)
Returns the value to which the given key is mapped. |
Object |
get(Object ok)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key.
|
int |
growthFactor()
Gets the growth factor. |
void |
growthFactor(int growthFactor)
Sets the growth factor. |
int |
hashCode()
Returns a hash code for this map. |
Byte2ByteSortedMap |
headMap(byte to)
|
boolean |
isEmpty()
|
Set |
keySet()
Returns a type-specific-sorted-set view of the keys of this map. |
byte |
lastByteKey()
Returns the last key of this map in iteration order. |
byte |
put(byte k,
byte v)
Adds a pair to the map. |
Object |
put(Object ok,
Object ov)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key.
|
boolean |
rehash()
Rehashes this map without changing the table size. |
byte |
remove(byte k)
Removes the mapping with the given key. |
Object |
remove(Object ok)
Delegates to the corresponding type-specific method, taking care of returning null on a missing key.
|
int |
size()
|
Byte2ByteSortedMap |
subMap(byte from,
byte to)
|
Byte2ByteSortedMap |
tailMap(byte from)
|
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. |
Collection |
values()
Returns a type-specific-set view of the values of this map. |
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ByteSortedMap |
firstKey, headMap, lastKey, subMap, tailMap |
Methods inherited from class it.unimi.dsi.fastutil.bytes.AbstractByte2ByteMap |
containsKey, containsValue, defaultReturnValue, defaultReturnValue, equals, getDefRetValue, putAll, setDefRetValue, toString |
Methods inherited from class java.lang.Object |
getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface it.unimi.dsi.fastutil.bytes.Byte2ByteMap |
defaultReturnValue, defaultReturnValue, getDefRetValue, setDefRetValue |
Methods inherited from interface java.util.Map |
containsKey, containsValue, equals, putAll |
Methods inherited from interface java.util.SortedMap |
firstKey, headMap, lastKey, subMap, tailMap |
Field Detail |
public static final long serialVersionUID
Constructor Detail |
public Byte2ByteLinkedOpenHashMap(int n, float f)
n
/f
.
n
- the expected number of elements in the hash map.f
- the load factor.Hash.PRIMES
public Byte2ByteLinkedOpenHashMap(int n)
Hash.DEFAULT_LOAD_FACTOR
as load factor.
n
- the expected number of elements in the hash map.public Byte2ByteLinkedOpenHashMap()
Hash.DEFAULT_INITIAL_SIZE
entries
and Hash.DEFAULT_LOAD_FACTOR
as load factor.
public Byte2ByteLinkedOpenHashMap(Map m, float f)
m
- a Map
to be copied into the new hash map.f
- the load factor.public Byte2ByteLinkedOpenHashMap(Map m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given one.
m
- a Map
to be copied into the new hash map.public Byte2ByteLinkedOpenHashMap(Byte2ByteMap m, float f)
m
- a type-specific map to be copied into the new hash map.f
- the load factor.public Byte2ByteLinkedOpenHashMap(Byte2ByteMap m)
Hash.DEFAULT_LOAD_FACTOR
as load factor copying a given type-specific one.
m
- a type-specific map to be copied into the new hash map.Method Detail |
public void growthFactor(int growthFactor)
growthFactor
- the new growth factor; it must be positive.public int growthFactor()
growthFactor(int)
public byte put(byte k, byte v)
Byte2ByteMap
put
in interface Byte2ByteMap
put
in class AbstractByte2ByteMap
public Object put(Object ok, Object ov)
AbstractByte2ByteMap
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.
put
in interface Map
put
in class AbstractByte2ByteMap
public boolean containsValue(byte v)
AbstractByte2ByteMap
AbstractByte2ByteMap.values()
.
containsValue
in interface Byte2ByteMap
containsValue
in class AbstractByte2ByteMap
public void clear()
clear
in interface Map
clear
in class AbstractByte2ByteMap
public byte firstByteKey()
firstByteKey
in interface Byte2ByteSortedMap
SortedMap.firstKey()
public byte lastByteKey()
lastByteKey
in interface Byte2ByteSortedMap
SortedMap.lastKey()
public Comparator comparator()
comparator
in interface SortedMap
public Byte2ByteSortedMap tailMap(byte from)
tailMap
in interface Byte2ByteSortedMap
SortedMap.tailMap(Object)
public Byte2ByteSortedMap headMap(byte to)
headMap
in interface Byte2ByteSortedMap
SortedMap.headMap(Object)
public Byte2ByteSortedMap subMap(byte from, byte to)
subMap
in interface Byte2ByteSortedMap
SortedMap.subMap(Object,Object)
public boolean containsKey(byte k)
AbstractByte2ByteMap
AbstractByte2ByteMap.keySet()
.
containsKey
in interface Byte2ByteMap
containsKey
in class AbstractByte2ByteMap
public int size()
size
in interface Map
public boolean isEmpty()
isEmpty
in interface Map
isEmpty
in class AbstractByte2ByteMap
public byte get(byte k)
Byte2ByteMap
get
in interface Byte2ByteMap
k
- the key.
Map.get(Object)
public byte remove(byte k)
Byte2ByteMap
remove
in interface Byte2ByteMap
remove
in class AbstractByte2ByteMap
public Object get(Object ok)
AbstractByte2ByteMap
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.
get
in interface Map
get
in class AbstractByte2ByteMap
public Object remove(Object ok)
AbstractByte2ByteMap
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.
remove
in interface Map
remove
in class AbstractByte2ByteMap
public Set entrySet()
entrySet
in interface Map
public Set keySet()
AbstractByte2ByteSortedMap
The view is backed by the sorted set returned by Map.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.
keySet
in interface Map
keySet
in class AbstractByte2ByteSortedMap
public Collection values()
AbstractByte2ByteMap
The view is backed by the set returned by Map.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.
values
in interface Map
values
in class AbstractByte2ByteMap
public boolean rehash()
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()
.
true
if there was enough memory to rehash the map, false
otherwise.trim()
public boolean trim()
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 optimise 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()
.
trim(int)
,
rehash()
public boolean trim(int n)
Let N be the smallest table size that can hold
max(n,
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.
size()
)
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.
n
- the threshold for the trimming.
trim()
,
rehash()
public Object clone()
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.
public int hashCode()
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.
hashCode
in interface Map
hashCode
in class AbstractByte2ByteMap
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