@Generated(date="2014-01-02T13:00:32+0000",
value="HPPC generated from: DoubleCharOpenHashMap.java")
public class DoubleCharOpenHashMap
extends java.lang.Object
implements DoubleCharMap, java.lang.Cloneable
double to char, implemented using open
addressing with linear probing for collision resolution.
The internal buffers of this implementation (keys, values,
allocated) are always allocated to the nearest size that is a power of two. When
the capacity exceeds the given load factor, the buffer size is doubled.
See ObjectObjectOpenHashMap class for API similarities and differences against Java
Collections.
Important node. The implementation uses power-of-two tables and linear
probing, which may cause poor performance (many collisions) if hash values are
not properly distributed. This implementation uses rehashing
using MurmurHash3.
| Modifier and Type | Class and Description |
|---|---|
class |
DoubleCharOpenHashMap.KeysContainer
A view of the keys inside this hash map.
|
| Modifier and Type | Field and Description |
|---|---|
boolean[] |
allocated
Information if an entry (slot) in the
values table is allocated
or empty. |
int |
assigned
Cached number of assigned slots in
allocated. |
static int |
DEFAULT_CAPACITY
Default capacity.
|
static float |
DEFAULT_LOAD_FACTOR
Default load factor.
|
double[] |
keys
Hash-indexed array holding all keys.
|
protected int |
lastSlot
The most recent slot accessed in
containsKey(double) (required for
lget()). |
float |
loadFactor
The load factor for this map (fraction of allocated slots
before the buffers must be rehashed or reallocated).
|
static int |
MIN_CAPACITY
Minimum capacity for the map.
|
protected int |
perturbation
We perturb hashed values with the array size to avoid problems with
nearly-sorted-by-hash values on iterations.
|
protected int |
resizeAt
Resize buffers when
allocated hits this value. |
char[] |
values
Hash-indexed array holding all values associated to the keys
stored in
keys. |
| Constructor and Description |
|---|
DoubleCharOpenHashMap()
|
DoubleCharOpenHashMap(DoubleCharAssociativeContainer container)
Create a hash map from all key-value pairs of another container.
|
DoubleCharOpenHashMap(int initialCapacity)
Creates a hash map with the given initial capacity, default load factor of
0.75f.
|
DoubleCharOpenHashMap(int initialCapacity,
float loadFactor)
Creates a hash map with the given initial capacity,
load factor.
|
| Modifier and Type | Method and Description |
|---|---|
char |
addTo(double key,
char additionValue)
An equivalent of calling
|
void |
clear()
Clear all keys and values in the container.
|
DoubleCharOpenHashMap |
clone() |
protected int |
computePerturbationValue(int capacity)
Compute the key perturbation value applied before hashing.
|
boolean |
containsKey(double key)
Returns
true if this container has an association to a value for
the given key. |
boolean |
equals(java.lang.Object obj)
Compares the specified object with this set for equality.
|
<T extends DoubleCharProcedure> |
forEach(T procedure)
Applies a given procedure to all keys-value pairs in this container.
|
static DoubleCharOpenHashMap |
from(double[] keys,
char[] values)
Creates a hash map from two index-aligned arrays of key-value pairs.
|
static DoubleCharOpenHashMap |
from(DoubleCharAssociativeContainer container)
Create a hash map from another associative container.
|
char |
get(double key) |
char |
getOrDefault(double key,
char defaultValue) |
int |
hashCode() |
boolean |
isEmpty() |
java.util.Iterator<DoubleCharCursor> |
iterator()
Returns a cursor over the entries (key-value pairs) in this map.
|
DoubleCharOpenHashMap.KeysContainer |
keys()
Returns a specialized view of the keys of this associated container.
|
char |
lget()
Returns the last value saved in a call to
containsKey(double). |
char |
lset(char key)
Sets the value corresponding to the key saved in the last
call to
containsKey(double), if and only if the key exists
in the map already. |
int |
lslot() |
static DoubleCharOpenHashMap |
newInstance()
Create a new hash map without providing the full generic signature (constructor
shortcut).
|
static DoubleCharOpenHashMap |
newInstance(int initialCapacity,
float loadFactor)
Create a new hash map without providing the full generic signature (constructor
shortcut).
|
static DoubleCharOpenHashMap |
newInstanceWithoutPerturbations()
Returns a new object with no key perturbations (see
computePerturbationValue(int)). |
char |
put(double key,
char value)
Place a given key and value in the container.
|
int |
putAll(DoubleCharAssociativeContainer container)
Puts all keys from another container to this map, replacing the values
of existing keys, if such keys are present.
|
int |
putAll(java.lang.Iterable<? extends DoubleCharCursor> iterable)
Puts all key/value pairs from a given iterable into this map.
|
boolean |
putIfAbsent(double key,
char value)
Trove-inspired API method.
|
char |
putOrAdd(double key,
char putValue,
char additionValue)
Trove-inspired API method.
|
char |
remove(double key)
Remove all values at the given key.
|
int |
removeAll(DoubleContainer container)
Removes all keys (and associated values) present in a given container.
|
int |
removeAll(DoublePredicate predicate)
Removes all keys (and associated values) for which the predicate returns
true. |
protected void |
shiftConflictingKeys(int slotCurr)
Shift all the slot-conflicting keys allocated to (and including)
slot. |
int |
size() |
java.lang.String |
toString()
Convert the contents of this map to a human-friendly string.
|
CharContainer |
values()
Returns a container view of all values present in this container.
|
public static final int MIN_CAPACITY
public static final int DEFAULT_CAPACITY
public static final float DEFAULT_LOAD_FACTOR
public double[] keys
valuespublic char[] values
keys.keyspublic boolean[] allocated
values table is allocated
or empty.assignedpublic int assigned
allocated.public final float loadFactor
protected int resizeAt
allocated hits this value.protected int lastSlot
containsKey(double) (required for
lget()).containsKey(double),
lget()protected int perturbation
public DoubleCharOpenHashMap()
public DoubleCharOpenHashMap(int initialCapacity)
See class notes about hash distribution importance.
initialCapacity - Initial capacity (greater than zero and automatically
rounded to the next power of two).public DoubleCharOpenHashMap(int initialCapacity,
float loadFactor)
See class notes about hash distribution importance.
initialCapacity - Initial capacity (greater than zero and automatically
rounded to the next power of two).loadFactor - The load factor (greater than zero and smaller than 1).public DoubleCharOpenHashMap(DoubleCharAssociativeContainer container)
public char put(double key,
char value)
put in interface DoubleCharMappublic int putAll(DoubleCharAssociativeContainer container)
putAll in interface DoubleCharMappublic int putAll(java.lang.Iterable<? extends DoubleCharCursor> iterable)
putAll in interface DoubleCharMappublic boolean putIfAbsent(double key,
char value)
if (!map.containsKey(key)) map.put(value);
This method saves to lastSlot as a side effect of each call.
key - The key of the value to check.value - The value to put if key does not exist.true if key did not exist and value
was placed in the map.public char putOrAdd(double key,
char putValue,
char additionValue)
if (containsKey(key))
{
char v = (char) (lget() + additionValue);
lset(v);
return v;
}
else
{
put(key, putValue);
return putValue;
}
key - The key of the value to adjust.putValue - The value to put if key does not exist.additionValue - The value to add to the existing value if key exists.key (after changes).public char addTo(double key,
char additionValue)
if (containsKey(key))
{
char v = (char) (lget() + additionValue);
lset(v);
return v;
}
else
{
put(key, additionValue);
return additionValue;
}
key - The key of the value to adjust.additionValue - The value to put or add to the existing value if key exists.key (after changes).protected int computePerturbationValue(int capacity)
Compute the key perturbation value applied before hashing. The returned value should be non-zero and ideally different for each capacity. This matters because keys are nearly-ordered by their hashed values so when adding one container's values to the other, the number of collisions can skyrocket into the worst case possible.
If it is known that hash containers will not be added to each other (will be used for counting only, for example) then some speed can be gained by not perturbing keys before hashing and returning a value of zero for all possible capacities. The speed gain is a result of faster rehash operation (keys are mostly in order).
public char remove(double key)
remove in interface DoubleCharMapprotected void shiftConflictingKeys(int slotCurr)
slot.public int removeAll(DoubleContainer container)
keys().removeAll(container)but with no additional overhead.
removeAll in interface DoubleCharAssociativeContainerpublic int removeAll(DoublePredicate predicate)
true.
An alias to:
keys().removeAll(container)but with no additional overhead.
removeAll in interface DoubleCharAssociativeContainerpublic char get(double key)
Use the following snippet of code to check for key existence first and then retrieve the value if it exists.
if (map.containsKey(key)) value = map.lget();
The above code cannot be used by multiple concurrent
threads because a call to #containsKey(Object) stores
the temporary slot number in lastSlot. An alternative to the above
conditional statement is to use #getOrDefault(Object, Object) and
provide a custom default value sentinel (not present in the value set).
get in interface DoubleCharMappublic char getOrDefault(double key,
char defaultValue)
getOrDefault in interface DoubleCharMappublic char lget()
containsKey(double).containsKey(double)public char lset(char key)
containsKey(double), if and only if the key exists
in the map already.containsKey(double)public int lslot()
containsKey(double) if
it returned true.containsKey(double)public boolean containsKey(double key)
true if this container has an association to a value for
the given key.
Saves the associated value for fast access using lget()
or lset(char).
if (map.containsKey(key)) value = map.lget();or, to modify the value at the given key without looking up its slot twice:
if (map.containsKey(key)) map.lset(map.lget() + 1);*
Important: containsKey(double) and consecutive lget(), lset(char)
or #lkey must not be used by concurrent threads because lastSlot is
used to store state.
containsKey in interface DoubleCharAssociativeContainerpublic void clear()
Does not release internal buffers.
clear in interface DoubleCharAssociativeContainerpublic int size()
size in interface DoubleCharAssociativeContainerpublic boolean isEmpty()
Note that an empty container may still contain many deleted keys (that occupy buffer space). Adding even a single element to such a container may cause rehashing.
isEmpty in interface DoubleCharAssociativeContainertrue if this hash map contains no assigned keys.public int hashCode()
hashCode in interface DoubleCharMaphashCode in class java.lang.Objectpublic boolean equals(java.lang.Object obj)
DoubleCharMap and both objects contains exactly the same key-value pairs.equals in interface DoubleCharMapequals in class java.lang.Objectpublic java.util.Iterator<DoubleCharCursor> iterator()
Iterator.next(). To read the current key and value use the cursor's
public fields. An example is shown below.
for (IntShortCursor c : intShortMap)
{
System.out.println("index=" + c.index
+ " key=" + c.key
+ " value=" + c.value);
}
The index field inside the cursor gives the internal index inside
the container's implementation. The interpretation of this index depends on
to the container.
iterator in interface DoubleCharAssociativeContaineriterator in interface java.lang.Iterable<DoubleCharCursor>public <T extends DoubleCharProcedure> T forEach(T procedure)
DoubleCharProcedure. This lets the caller to call methods of the argument
by chaining the call (even if the argument is an anonymous type) to retrieve computed values,
for example.forEach in interface DoubleCharAssociativeContainerpublic DoubleCharOpenHashMap.KeysContainer keys()
ObjectLookupContainer.keys in interface DoubleCharAssociativeContainerpublic CharContainer values()
DoubleCharAssociativeContainervalues in interface DoubleCharAssociativeContainerpublic DoubleCharOpenHashMap clone()
clone in class java.lang.Objectpublic java.lang.String toString()
toString in class java.lang.Objectpublic static DoubleCharOpenHashMap from(double[] keys, char[] values)
public static DoubleCharOpenHashMap from(DoubleCharAssociativeContainer container)
public static DoubleCharOpenHashMap newInstance()
public static DoubleCharOpenHashMap newInstanceWithoutPerturbations()
computePerturbationValue(int)). Only use when sure the container will not
be used for direct copying of keys to another hash container.public static DoubleCharOpenHashMap newInstance(int initialCapacity, float loadFactor)
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