DoubleByteHashMap

java.lang.Object
- com.carrotsearch.hppc.DoubleByteHashMap

All Implemented Interfaces:

DoubleByteAssociativeContainer, DoubleByteMap, Preallocable, java.lang.Cloneable, java.lang.Iterable<DoubleByteCursor>

Direct Known Subclasses:

DoubleByteScatterMap
```
@Generated(date="2023-04-24T17:14:49+0800",
           value="KTypeVTypeHashMap.java")
public class DoubleByteHashMap
extends java.lang.Object
implements DoubleByteMap, Preallocable, java.lang.Cloneable
```
A hash map of double to byte, implemented using open addressing with linear probing for collision resolution.
Note: read about important differences between hash and scatter sets.

See Also:

DoubleByteScatterMap, HPPC interfaces diagram

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`private class`	`DoubleByteHashMap.EntryIterator` An iterator implementation for `iterator()`.
`class`	`DoubleByteHashMap.KeysContainer` A view of the keys inside this hash map.
`private class`	`DoubleByteHashMap.KeysIterator` An iterator over the set of assigned keys.
`private class`	`DoubleByteHashMap.ValuesContainer` A view over the set of values of this map.
`private class`	`DoubleByteHashMap.ValuesIterator` An iterator over the set of assigned values.

Field Summary

Fields
Modifier and Type	Field and Description
`protected int`	`assigned` The number of stored keys (assigned key slots), excluding the special "empty" key, if any (use `size()` instead).
`protected boolean`	`hasEmptyKey` Special treatment for the "empty slot" key marker.
`protected int`	`keyMixer` We perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.
`double[]`	`keys` The array holding keys.
`protected double`	`loadFactor` The load factor for `keys`.
`protected int`	`mask` Mask for slot scans in `keys`.
`protected HashOrderMixingStrategy`	`orderMixer` Per-instance hash order mixing strategy.
`protected int`	`resizeAt` Expand (rehash) `keys` when `assigned` hits this value.
`byte[]`	`values` The array holding values.

Constructor Summary

Constructors
Constructor and Description
`DoubleByteHashMap()` New instance with sane defaults.
`DoubleByteHashMap(DoubleByteAssociativeContainer container)` Create a hash map from all key-value pairs of another container.
`DoubleByteHashMap(int expectedElements)` New instance with sane defaults.
`DoubleByteHashMap(int expectedElements, double loadFactor)` New instance with sane defaults.
`DoubleByteHashMap(int expectedElements, double loadFactor, HashOrderMixingStrategy orderMixer)` New instance with the provided defaults.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`byte`	`addTo(double key, byte incrementValue)` Adds `incrementValue` to any existing value for the given `key` or inserts `incrementValue` if `key` did not previously exist.
`protected void`	`allocateBuffers(int arraySize)` Allocate new internal buffers.
`protected void`	`allocateThenInsertThenRehash(int slot, double pendingKey, byte pendingValue)` This method is invoked when there is a new key/ value pair to be inserted into the buffers but there is not enough empty slots to do so.
`void`	`clear()` Clear all keys and values in the container.
`DoubleByteHashMap`	`clone()`
`boolean`	`containsKey(double key)` Returns `true` if this container has an association to a value for the given key.
`void`	`ensureCapacity(int expectedElements)` Ensure this container can hold at least the given number of keys (entries) without resizing its buffers.
`protected boolean`	`equalElements(DoubleByteHashMap other)` Return true if all keys of some other container exist in this container.
`boolean`	`equals(java.lang.Object obj)` Compares the specified object with this set for equality.
`<T extends DoubleBytePredicate> T`	`forEach(T predicate)` Applies a given predicate to all keys-value pairs in this container.
`<T extends DoubleByteProcedure> T`	`forEach(T procedure)` Applies a given procedure to all keys-value pairs in this container.
`static DoubleByteHashMap`	`from(double[] keys, byte[] values)` Creates a hash map from two index-aligned arrays of key-value pairs.
`byte`	`get(double key)`
`byte`	`getOrDefault(double key, byte defaultValue)`
`int`	`hashCode()`
`protected int`	`hashKey(double key)` Returns a hash code for the given key.
`boolean`	`indexExists(int index)`
`byte`	`indexGet(int index)` Returns the value associated with an existing key.
`void`	`indexInsert(int index, double key, byte value)` Inserts a key-value pair for a key that is not present in the map.
`int`	`indexOf(double key)` Returns a logical "index" of a given key that can be used to speed up follow-up value setters or getters in certain scenarios (conditional logic).
`byte`	`indexReplace(int index, byte newValue)` Replaces the value associated with an existing key and returns any previous value stored for that key.
`boolean`	`isEmpty()`
`java.util.Iterator<DoubleByteCursor>`	`iterator()` Returns a cursor over the entries (key-value pairs) in this map.
`DoubleByteHashMap.KeysContainer`	`keys()` Returns a specialized view of the keys of this associated container.
`byte`	`put(double key, byte value)` Place a given key and value in the container.
`int`	`putAll(DoubleByteAssociativeContainer 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 DoubleByteCursor> iterable)` Puts all key/value pairs from a given iterable into this map.
`boolean`	`putIfAbsent(double key, byte value)` Trove-inspired API method.
`byte`	`putOrAdd(double key, byte putValue, byte incrementValue)` If `key` exists, `putValue` is inserted into the map, otherwise any existing value is incremented by `additionValue`.
`protected void`	`rehash(double[] fromKeys, byte[] fromValues)` Rehash from old buffers to new buffers.
`void`	`release()` Removes all elements from the collection and additionally releases any internal buffers.
`byte`	`remove(double key)` Remove all values at the given key.
`int`	`removeAll(DoubleBytePredicate predicate)` Removes all keys (and associated values) for which the predicate returns `true`.
`int`	`removeAll(DoubleContainer other)` 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 gapSlot)` Shift all the slot-conflicting keys and values allocated to (and including) `slot`.
`int`	`size()`
`java.lang.String`	`toString()` Convert the contents of this map to a human-friendly string.
`ByteCollection`	`values()` Returns a container view of all values present in this container.
`protected double`	`verifyLoadFactor(double loadFactor)` Validate load factor range and return it.
`java.lang.String`	`visualizeKeyDistribution(int characters)` Visually depict the distribution of keys.

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

Methods inherited from interface java.lang.Iterable
forEach, spliterator

- Field Detail
  - keys
```
public double[] keys
```
    The array holding keys.
  - values
```
public byte[] values
```
    The array holding values.
  - keyMixer
```
protected int keyMixer
```
    We perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.
    
    See Also:
    
    hashKey(double), "http://issues.carrot2.org/browse/HPPC-80", "http://issues.carrot2.org/browse/HPPC-103"
  - assigned
```
protected int assigned
```
    The number of stored keys (assigned key slots), excluding the special "empty" key, if any (use size() instead).
    
    See Also:
    
    size()
  - mask
```
protected int mask
```
    Mask for slot scans in keys.
  - resizeAt
```
protected int resizeAt
```
    Expand (rehash) keys when assigned hits this value.
  - hasEmptyKey
```
protected boolean hasEmptyKey
```
    Special treatment for the "empty slot" key marker.
  - loadFactor
```
protected double loadFactor
```
    The load factor for keys.
  - orderMixer
```
protected HashOrderMixingStrategy orderMixer
```
    Per-instance hash order mixing strategy.
    
    See Also:
    
    keyMixer
- Constructor Detail
  - DoubleByteHashMap
```
public DoubleByteHashMap()
```
    New instance with sane defaults.
  - DoubleByteHashMap
```
public DoubleByteHashMap(int expectedElements)
```
    New instance with sane defaults.
    
    Parameters:
    
    expectedElements - The expected number of elements guaranteed not to cause buffer expansion (inclusive).
  - DoubleByteHashMap
```
public DoubleByteHashMap(int expectedElements,
                         double loadFactor)
```
    New instance with sane defaults.
    
    Parameters:
    
    expectedElements - The expected number of elements guaranteed not to cause buffer expansion (inclusive).
    
    loadFactor - The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by verifyLoadFactor(double).
  - DoubleByteHashMap
```
public DoubleByteHashMap(int expectedElements,
                         double loadFactor,
                         HashOrderMixingStrategy orderMixer)
```
    New instance with the provided defaults.
    
    Parameters:
    
    expectedElements - The expected number of elements guaranteed not to cause a rehash (inclusive).
    
    loadFactor - The load factor for internal buffers. Insane load factors (zero, full capacity) are rejected by verifyLoadFactor(double).
    
    orderMixer - Hash key order mixing strategy. See HashOrderMixing for predefined implementations. Use constant mixers only if you understand the potential consequences.
  - DoubleByteHashMap
```
public DoubleByteHashMap(DoubleByteAssociativeContainer container)
```
    Create a hash map from all key-value pairs of another container.
- Method Detail
  - put
```
public byte put(double key,
                byte value)
```
    Place a given key and value in the container.
    
    Specified by:
    
    put in interface DoubleByteMap
    
    Returns:
    
    The value previously stored under the given key in the map is returned.
  - putAll
```
public int putAll(DoubleByteAssociativeContainer container)
```
    Puts all keys from another container to this map, replacing the values of existing keys, if such keys are present.
    
    Specified by:
    
    putAll in interface DoubleByteMap
    
    Returns:
    
    Returns the number of keys added to the map as a result of this call (not previously present in the map). Values of existing keys are overwritten.
  - putAll
```
public int putAll(java.lang.Iterable<? extends DoubleByteCursor> iterable)
```
    Puts all key/value pairs from a given iterable into this map.
    
    Specified by:
    
    putAll in interface DoubleByteMap
    
    Returns:
    
    Returns the number of keys added to the map as a result of this call (not previously present in the map). Values of existing keys are overwritten.
  - putIfAbsent
```
public boolean putIfAbsent(double key,
                           byte value)
```
    Trove-inspired API method. An equivalent of the following code:
```
 if (!map.containsKey(key)) map.put(value);
 
```
    Parameters:
    
    key - The key of the value to check.
    
    value - The value to put if key does not exist.
    
    Returns:
    
    true if key did not exist and value was placed in the map.
  - putOrAdd
```
public byte putOrAdd(double key,
                     byte putValue,
                     byte incrementValue)
```
    If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.
    
    Specified by:
    
    putOrAdd in interface DoubleByteMap
    
    Parameters:
    
    key - The key of the value to adjust.
    
    putValue - The value to put if key does not exist.
    
    incrementValue - The value to add to the existing value if key exists.
    
    Returns:
    
    Returns the current value associated with key (after changes).
  - addTo
```
public byte addTo(double key,
                  byte incrementValue)
```
    Adds incrementValue to any existing value for the given key or inserts incrementValue if key did not previously exist.
    
    Specified by:
    
    addTo in interface DoubleByteMap
    
    Parameters:
    
    key - The key of the value to adjust.
    
    incrementValue - The value to put or add to the existing value if key exists.
    
    Returns:
    
    Returns the current value associated with key (after changes).
  - remove
```
public byte remove(double key)
```
    Remove all values at the given key. The default value for the key type is returned if the value does not exist in the map.
    
    Specified by:
    
    remove in interface DoubleByteMap
  - removeAll
```
public int removeAll(DoubleContainer other)
```
    Removes all keys (and associated values) present in a given container. An alias to:
```
 keys().removeAll(container)
 
```
    but with no additional overhead.
    Specified by:
    
    removeAll in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Returns the number of elements actually removed as a result of this call.
  - removeAll
```
public int removeAll(DoubleBytePredicate predicate)
```
    Removes all keys (and associated values) for which the predicate returns true.
    
    Specified by:
    
    removeAll in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Returns the number of elements actually removed as a result of this call.
  - removeAll
```
public int removeAll(DoublePredicate predicate)
```
    Removes all keys (and associated values) for which the predicate returns true.
    
    Specified by:
    
    removeAll in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Returns the number of elements actually removed as a result of this call.
  - get
```
public byte get(double key)
```
    Specified by:
    
    get in interface DoubleByteMap
    
    Returns:
    
    Returns the value associated with the given key or the default value for the key type, if the key is not associated with any value. Important note: For primitive type values, the value returned for a non-existing key may not be the default value of the primitive type (it may be any value previously assigned to that slot).
  - getOrDefault
```
public byte getOrDefault(double key,
                         byte defaultValue)
```
    Specified by:
    
    getOrDefault in interface DoubleByteMap
    
    Returns:
    
    Returns the value associated with the given key or the provided default value if the key is not associated with any value.
  - containsKey
```
public boolean containsKey(double key)
```
    Returns true if this container has an association to a value for the given key.
    
    Specified by:
    
    containsKey in interface DoubleByteAssociativeContainer
  - indexOf
```
public int indexOf(double key)
```
    Returns a logical "index" of a given key that can be used to speed up follow-up value setters or getters in certain scenarios (conditional logic). The semantics of "indexes" are not strictly defined. Indexes may (and typically won't be) contiguous. The index is valid only between map modifications (it will not be affected by read-only operations like iteration or value retrievals).
    
    Specified by:
    
    indexOf in interface DoubleByteMap
    
    Parameters:
    
    key - The key to locate in the map.
    
    Returns:
    
    A non-negative value of the logical "index" of the key in the map or a negative value if the key did not exist.
    
    See Also:
    
    DoubleByteMap.indexExists(int), DoubleByteMap.indexGet(int), DoubleByteMap.indexInsert(int, double, byte), DoubleByteMap.indexReplace(int, byte)
  - indexExists
```
public boolean indexExists(int index)
```
    Specified by:
    
    indexExists in interface DoubleByteMap
    
    Parameters:
    
    index - The index of a given key, as returned from DoubleByteMap.indexOf(double).
    
    Returns:
    
    Returns true if the index corresponds to an existing key or false otherwise. This is equivalent to checking whether the index is a positive value (existing keys) or a negative value (non-existing keys).
    
    See Also:
    
    DoubleByteMap.indexOf(double)
  - indexGet
```
public byte indexGet(int index)
```
    Returns the value associated with an existing key.
    
    Specified by:
    
    indexGet in interface DoubleByteMap
    
    Parameters:
    
    index - The index of an existing key.
    
    Returns:
    
    Returns the value currently associated with the key.
    
    See Also:
    
    DoubleByteMap.indexOf(double)
  - indexReplace
```
public byte indexReplace(int index,
                         byte newValue)
```
    Replaces the value associated with an existing key and returns any previous value stored for that key.
    
    Specified by:
    
    indexReplace in interface DoubleByteMap
    
    Parameters:
    
    index - The index of an existing key.
    
    Returns:
    
    Returns the previous value associated with the key.
    
    See Also:
    
    DoubleByteMap.indexOf(double)
  - indexInsert
```
public void indexInsert(int index,
                        double key,
                        byte value)
```
    Inserts a key-value pair for a key that is not present in the map. This method may help in avoiding double recalculation of the key's hash.
    
    Specified by:
    
    indexInsert in interface DoubleByteMap
    
    Parameters:
    
    index - The index of a previously non-existing key, as returned from DoubleByteMap.indexOf(double).
    
    See Also:
    
    DoubleByteMap.indexOf(double)
  - clear
```
public void clear()
```
    Clear all keys and values in the container.
    
    Specified by:
    
    clear in interface DoubleByteMap
    
    See Also:
    
    DoubleByteMap.release()
  - release
```
public void release()
```
    Removes all elements from the collection and additionally releases any internal buffers. Typically, if the object is to be reused, a simple DoubleByteMap.clear() should be a better alternative since it'll avoid reallocation.
    
    Specified by:
    
    release in interface DoubleByteMap
    
    See Also:
    
    DoubleByteMap.clear()
  - size
```
public int size()
```
    Specified by:
    
    size in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Returns the current size (number of assigned keys) in the container.
  - isEmpty
```
public boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Return true if this hash map contains no assigned keys.
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface DoubleByteMap
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    Returns:
    
    A hash code of elements stored in the map. The hash code is defined as a sum of hash codes of keys and values stored within the set). Because sum is commutative, this ensures that different order of elements in a set does not affect the hash code.
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Compares the specified object with this set for equality. Returns true if and only if the specified object is also a DoubleByteMap and both objects contains exactly the same key-value pairs.
    
    Specified by:
    
    equals in interface DoubleByteMap
    
    Overrides:
    
    equals in class java.lang.Object
  - equalElements
```
protected boolean equalElements(DoubleByteHashMap other)
```
    Return true if all keys of some other container exist in this container.
  - ensureCapacity
```
public void ensureCapacity(int expectedElements)
```
    Ensure this container can hold at least the given number of keys (entries) without resizing its buffers.
    
    Specified by:
    
    ensureCapacity in interface Preallocable
    
    Parameters:
    
    expectedElements - The total number of keys, inclusive.
  - iterator
```
public java.util.Iterator<DoubleByteCursor> iterator()
```
    Returns a cursor over the entries (key-value pairs) in this map. The iterator is implemented as a cursor and it returns the same cursor instance on every call to 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.
    Specified by:
    
    iterator in interface DoubleByteAssociativeContainer
    
    Specified by:
    
    iterator in interface java.lang.Iterable<DoubleByteCursor>
  - forEach
```
public <T extends DoubleByteProcedure> T forEach(T procedure)
```
    Applies a given procedure to all keys-value pairs in this container. Returns the argument (any subclass of DoubleByteProcedure. 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.
    
    Specified by:
    
    forEach in interface DoubleByteAssociativeContainer
  - forEach
```
public <T extends DoubleBytePredicate> T forEach(T predicate)
```
    Applies a given predicate to all keys-value pairs in this container. Returns the argument (any subclass of DoubleBytePredicate. 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. The iteration is continued as long as the predicate returns true.
    
    Specified by:
    
    forEach in interface DoubleByteAssociativeContainer
  - keys
```
public DoubleByteHashMap.KeysContainer keys()
```
    Returns a specialized view of the keys of this associated container. The view additionally implements ObjectLookupContainer.
    
    Specified by:
    
    keys in interface DoubleByteAssociativeContainer
  - values
```
public ByteCollection values()
```
    Description copied from interface: DoubleByteAssociativeContainer
    
    Returns a container view of all values present in this container. The returned collection is a view over the key set and any modifications (if allowed) introduced to the collection will propagate to the associative container immediately.
    
    Specified by:
    
    values in interface DoubleByteAssociativeContainer
    
    Returns:
    
    Returns a container with all values stored in this map.
  - clone
```
public DoubleByteHashMap clone()
```
    Overrides:
    
    clone in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Convert the contents of this map to a human-friendly string.
    
    Overrides:
    
    toString in class java.lang.Object
  - visualizeKeyDistribution
```
public java.lang.String visualizeKeyDistribution(int characters)
```
    Description copied from interface: DoubleByteMap
    
    Visually depict the distribution of keys.
    
    Specified by:
    
    visualizeKeyDistribution in interface DoubleByteMap
    
    Parameters:
    
    characters - The number of characters to "squeeze" the entire buffer into.
    
    Returns:
    
    Returns a sequence of characters where '.' depicts an empty fragment of the internal buffer and 'X' depicts full or nearly full capacity within the buffer's range and anything between 1 and 9 is between.
  - from
```
public static DoubleByteHashMap from(double[] keys,
                                     byte[] values)
```
    Creates a hash map from two index-aligned arrays of key-value pairs.
  - hashKey
```
protected int hashKey(double key)
```
    Returns a hash code for the given key.
    The default implementation mixes the hash of the key with keyMixer to differentiate hash order of keys between hash containers. Helps alleviate problems resulting from linear conflict resolution in open addressing.
    
    The output from this function should evenly distribute keys across the entire integer range.
  - verifyLoadFactor
```
protected double verifyLoadFactor(double loadFactor)
```
    Validate load factor range and return it. Override and suppress if you need insane load factors.
  - rehash
```
protected void rehash(double[] fromKeys,
                      byte[] fromValues)
```
    Rehash from old buffers to new buffers.
  - allocateBuffers
```
protected void allocateBuffers(int arraySize)
```
    Allocate new internal buffers. This method attempts to allocate and assign internal buffers atomically (either allocations succeed or not).
  - allocateThenInsertThenRehash
```
protected void allocateThenInsertThenRehash(int slot,
                                            double pendingKey,
                                            byte pendingValue)
```
    This method is invoked when there is a new key/ value pair to be inserted into the buffers but there is not enough empty slots to do so. New buffers are allocated. If this succeeds, we know we can proceed with rehashing so we assign the pending element to the previous buffer (possibly violating the invariant of having at least one empty slot) and rehash all keys, substituting new buffers at the end.
  - shiftConflictingKeys
```
protected void shiftConflictingKeys(int gapSlot)
```
    Shift all the slot-conflicting keys and values allocated to (and including) slot.

Class DoubleByteHashMap

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.lang.Iterable

Field Detail

keys

values

keyMixer

assigned

mask

resizeAt

hasEmptyKey

loadFactor

orderMixer

Constructor Detail

DoubleByteHashMap

DoubleByteHashMap

DoubleByteHashMap

DoubleByteHashMap

DoubleByteHashMap

Method Detail

put

putAll

putAll

putIfAbsent

putOrAdd

addTo

remove

removeAll

removeAll

removeAll

get

getOrDefault

containsKey

indexOf

indexExists

indexGet

indexReplace

indexInsert

clear

release

size

isEmpty

hashCode

equals

equalElements

ensureCapacity

iterator

forEach

forEach

keys

values

clone

toString

visualizeKeyDistribution

from

hashKey

verifyLoadFactor

rehash

allocateBuffers

allocateThenInsertThenRehash

shiftConflictingKeys