Package com.carrotsearch.hppc

Class ShortIntHashMap

java.lang.Object

com.carrotsearch.hppc.ShortIntHashMap

All Implemented Interfaces:

Preallocable, ShortIntAssociativeContainer, ShortIntMap, java.lang.Cloneable, java.lang.Iterable<ShortIntCursor>

Direct Known Subclasses:

ShortIntScatterMap

@Generated(date="2018-05-21T11:30:39+0200",
           value="KTypeVTypeHashMap.java")
public class ShortIntHashMap
extends java.lang.Object
implements ShortIntMap, Preallocable, java.lang.Cloneable

A hash map of short to int, implemented using open addressing with linear probing for collision resolution.

Note: read about important differences between hash and scatter sets.

See Also:

ShortIntScatterMap, HPPC interfaces diagram

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	ShortIntHashMap.KeysContainer	A view of the keys inside this hash map.

Field Summary

Fields

Modifier and Type	Field	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.
short[]	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.
int[]	values	The array holding values.

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	Description
int	addTo(short key, int 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, short pendingKey, int 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.
ShortIntHashMap	clone()
boolean	containsKey(short 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(ShortIntHashMap 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 ShortIntProcedure> T	forEach(T procedure)	Applies a given procedure to all keys-value pairs in this container.
static ShortIntHashMap	from(short[] keys, int[] values)	Creates a hash map from two index-aligned arrays of key-value pairs.
int	get(short key)
int	getOrDefault(short key, int defaultValue)
int	hashCode()
protected int	hashKey(short key)	Returns a hash code for the given key.
boolean	indexExists(int index)
int	indexGet(int index)	Returns the value associated with an existing key.
void	indexInsert(int index, short key, int value)	Inserts a key-value pair for a key that is not present in the map.
int	indexOf(short 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).
int	indexReplace(int index, int newValue)	Replaces the value associated with an existing key and returns any previous value stored for that key.
boolean	isEmpty()
java.util.Iterator<ShortIntCursor>	iterator()	Returns a cursor over the entries (key-value pairs) in this map.
ShortIntHashMap.KeysContainer	keys()	Returns a specialized view of the keys of this associated container.
int	put(short key, int value)	Place a given key and value in the container.
int	putAll(ShortIntAssociativeContainer 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 ShortIntCursor> iterable)	Puts all key/value pairs from a given iterable into this map.
boolean	putIfAbsent(short key, int value)	Trove-inspired API method.
int	putOrAdd(short key, int putValue, int incrementValue)	If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.
protected void	rehash(short[] fromKeys, int[] fromValues)	Rehash from old buffers to new buffers.
void	release()	Removes all elements from the collection and additionally releases any internal buffers.
int	remove(short key)	Remove all values at the given key.
int	removeAll(ShortIntPredicate predicate)	Removes all keys (and associated values) for which the predicate returns true.
int	removeAll(ShortPredicate predicate)	Removes all keys (and associated values) for which the predicate returns true.
int	removeAll(ShortContainer other)	Removes all keys (and associated values) present in a given container.
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.
IntCollection	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 interface java.lang.Iterable

forEach, spliterator

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

keys

public short[] keys

The array holding keys.

values

public int[] 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(short), "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

ShortIntHashMap

public ShortIntHashMap()

New instance with sane defaults.

ShortIntHashMap

public ShortIntHashMap(int expectedElements)

New instance with sane defaults.

Parameters:

expectedElements - The expected number of elements guaranteed not to cause buffer expansion (inclusive).

ShortIntHashMap

public ShortIntHashMap(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).

ShortIntHashMap

public ShortIntHashMap(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.

ShortIntHashMap

public ShortIntHashMap(ShortIntAssociativeContainer container)

Create a hash map from all key-value pairs of another container.

Method Detail

put

public int put(short key,
               int value)

Place a given key and value in the container.

Specified by:

put in interface ShortIntMap

Returns:

The value previously stored under the given key in the map is returned.

putAll

public int putAll(ShortIntAssociativeContainer 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 ShortIntMap

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 ShortIntCursor> iterable)

Puts all key/value pairs from a given iterable into this map.

Specified by:

putAll in interface ShortIntMap

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(short key,
                           int 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 int putOrAdd(short key,
                    int putValue,
                    int incrementValue)

If key exists, putValue is inserted into the map, otherwise any existing value is incremented by additionValue.

Specified by:

putOrAdd in interface ShortIntMap

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 int addTo(short key,
                 int 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 ShortIntMap

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 int remove(short 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 ShortIntMap

removeAll

public int removeAll(ShortContainer 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 ShortIntAssociativeContainer

Returns:

Returns the number of elements actually removed as a result of this call.

removeAll

public int removeAll(ShortIntPredicate predicate)

Removes all keys (and associated values) for which the predicate returns true.

Specified by:

removeAll in interface ShortIntAssociativeContainer

Returns:

Returns the number of elements actually removed as a result of this call.

removeAll

public int removeAll(ShortPredicate predicate)

Removes all keys (and associated values) for which the predicate returns true.

Specified by:

removeAll in interface ShortIntAssociativeContainer

Returns:

Returns the number of elements actually removed as a result of this call.

get

public int get(short key)

Specified by:

get in interface ShortIntMap

Returns:

Returns the value associated with the given key or the default value for the value type, if the key is not associated with any value. For numeric value types, this default value is 0, for object types it is null.

getOrDefault

public int getOrDefault(short key,
                        int defaultValue)

Specified by:

getOrDefault in interface ShortIntMap

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(short key)

Returns true if this container has an association to a value for the given key.

Specified by:

containsKey in interface ShortIntAssociativeContainer

indexOf

public int indexOf(short 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 ShortIntMap

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:

ShortIntMap.indexExists(int), ShortIntMap.indexGet(int), ShortIntMap.indexInsert(int, short, int), ShortIntMap.indexReplace(int, int)

indexExists

public boolean indexExists(int index)

Specified by:

indexExists in interface ShortIntMap

Parameters:

index - The index of a given key, as returned from ShortIntMap.indexOf(short).

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:

ShortIntMap.indexOf(short)

indexGet

public int indexGet(int index)

Returns the value associated with an existing key.

Specified by:

indexGet in interface ShortIntMap

Parameters:

index - The index of an existing key.

Returns:

Returns the value currently associated with the key.

See Also:

ShortIntMap.indexOf(short)

indexReplace

public int indexReplace(int index,
                        int newValue)

Replaces the value associated with an existing key and returns any previous value stored for that key.

Specified by:

indexReplace in interface ShortIntMap

Parameters:

index - The index of an existing key.

Returns:

Returns the previous value associated with the key.

See Also:

ShortIntMap.indexOf(short)

indexInsert

public void indexInsert(int index,
                        short key,
                        int 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 ShortIntMap

Parameters:

index - The index of a previously non-existing key, as returned from ShortIntMap.indexOf(short).

See Also:

ShortIntMap.indexOf(short)

clear

public void clear()

Clear all keys and values in the container.

Specified by:

clear in interface ShortIntMap

See Also:

ShortIntMap.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 ShortIntMap.clear() should be a better alternative since it'll avoid reallocation.

Specified by:

release in interface ShortIntMap

See Also:

ShortIntMap.clear()

size

public int size()

Specified by:

size in interface ShortIntAssociativeContainer

Returns:

Returns the current size (number of assigned keys) in the container.

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface ShortIntAssociativeContainer

Returns:

Return true if this hash map contains no assigned keys.

hashCode

public int hashCode()

Specified by:

hashCode in interface ShortIntMap

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 ShortIntMap and both objects contains exactly the same key-value pairs.

Specified by:

equals in interface ShortIntMap

Overrides:

equals in class java.lang.Object

equalElements

protected boolean equalElements(ShortIntHashMap 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<ShortIntCursor> 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 java.lang.Iterable<ShortIntCursor>

Specified by:

iterator in interface ShortIntAssociativeContainer

forEach

public <T extends ShortIntProcedure> T forEach(T procedure)

Applies a given procedure to all keys-value pairs in this container. Returns the argument (any subclass of ShortIntProcedure. 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 ShortIntAssociativeContainer

forEach

public <T extends ShortIntPredicate> T forEach(T predicate)

Applies a given predicate to all keys-value pairs in this container. Returns the argument (any subclass of ShortIntPredicate. 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 ShortIntAssociativeContainer

keys

public ShortIntHashMap.KeysContainer keys()

Returns a specialized view of the keys of this associated container. The view additionally implements ObjectLookupContainer.

Specified by:

keys in interface ShortIntAssociativeContainer

values

public IntCollection values()

Description copied from interface: ShortIntAssociativeContainer

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 ShortIntAssociativeContainer

Returns:

Returns a container with all values stored in this map.

clone

public ShortIntHashMap 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: ShortIntMap

Visually depict the distribution of keys.

Specified by:

visualizeKeyDistribution in interface ShortIntMap

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 ShortIntHashMap from(short[] keys,
                                   int[] values)

Creates a hash map from two index-aligned arrays of key-value pairs.

hashKey

protected int hashKey(short 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(short[] fromKeys,
                      int[] 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,
                                            short pendingKey,
                                            int 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.