com.carrotsearch.hppc

Class ShortObjectHashMap<VType>

java.lang.Object

com.carrotsearch.hppc.ShortObjectHashMap<VType>

All Implemented Interfaces:

Preallocable, ShortObjectAssociativeContainer<VType>, ShortObjectMap<VType>, java.lang.Cloneable, java.lang.Iterable<ShortObjectCursor<VType>>

Direct Known Subclasses:

ShortObjectScatterMap

@Generated(date="2017-10-22T12:19:54+0200",
           value="KTypeVTypeHashMap.java")
public class ShortObjectHashMap<VType>
extends java.lang.Object
implements ShortObjectMap<VType>, Preallocable, java.lang.Cloneable

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

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

See Also:

ShortObjectScatterMap, HPPC interfaces diagram

Nested Class Summary

Nested Classes

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

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.
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.
java.lang.Object[]	values The array holding values.

Constructor Summary

Constructors

Constructor and Description
ShortObjectHashMap() New instance with sane defaults.
ShortObjectHashMap(int expectedElements) New instance with sane defaults.
ShortObjectHashMap(int expectedElements, double loadFactor) New instance with sane defaults.
ShortObjectHashMap(int expectedElements, double loadFactor, HashOrderMixingStrategy orderMixer) New instance with the provided defaults.
ShortObjectHashMap(ShortObjectAssociativeContainer<? extends VType> container) Create a hash map from all key-value pairs of another container.

Method Summary

Methods

Modifier and Type	Method and Description
protected void	allocateBuffers(int arraySize) Allocate new internal buffers.
protected void	allocateThenInsertThenRehash(int slot, short pendingKey, VType 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.
ShortObjectHashMap<VType>	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(ShortObjectHashMap<?> 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 ShortObjectPredicate<? super VType>> T	forEach(T predicate) Applies a given predicate to all keys-value pairs in this container.
<T extends ShortObjectProcedure<? super VType>> T	forEach(T procedure) Applies a given procedure to all keys-value pairs in this container.
static <VType> ShortObjectHashMap<VType>	from(short[] keys, VType[] values) Creates a hash map from two index-aligned arrays of key-value pairs.
VType	get(short key)
VType	getOrDefault(short key, VType defaultValue)
int	hashCode()
protected int	hashKey(short key) Returns a hash code for the given key.
boolean	indexExists(int index)
VType	indexGet(int index) Returns the value associated with an existing key.
void	indexInsert(int index, short key, VType 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).
VType	indexReplace(int index, VType newValue) Replaces the value associated with an existing key and returns any previous value stored for that key.
boolean	isEmpty()
java.util.Iterator<ShortObjectCursor<VType>>	iterator() Returns a cursor over the entries (key-value pairs) in this map.
ShortObjectHashMap.KeysContainer	keys() Returns a specialized view of the keys of this associated container.
VType	put(short key, VType value) Place a given key and value in the container.
int	putAll(java.lang.Iterable<? extends ShortObjectCursor<? extends VType>> iterable) Puts all key/value pairs from a given iterable into this map.
int	putAll(ShortObjectAssociativeContainer<? extends VType> container) Puts all keys from another container to this map, replacing the values of existing keys, if such keys are present.
boolean	putIfAbsent(short key, VType value) Trove-inspired API method.
protected void	rehash(short[] fromKeys, VType[] fromValues) Rehash from old buffers to new buffers.
void	release() Removes all elements from the collection and additionally releases any internal buffers.
VType	remove(short key) Remove all values at the given key.
int	removeAll(ShortContainer other) Removes all keys (and associated values) present in a given container.
int	removeAll(ShortObjectPredicate<? super VType> 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.
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.
ObjectCollection<VType>	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

Field Detail

keys

public short[] keys

The array holding keys.

values

public java.lang.Object[] 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

ShortObjectHashMap

public ShortObjectHashMap()

New instance with sane defaults.

ShortObjectHashMap

public ShortObjectHashMap(int expectedElements)

New instance with sane defaults.

Parameters:

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

ShortObjectHashMap

public ShortObjectHashMap(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).

ShortObjectHashMap

public ShortObjectHashMap(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.

ShortObjectHashMap

public ShortObjectHashMap(ShortObjectAssociativeContainer<? extends VType> container)

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

Method Detail

put

public VType put(short key,
        VType value)

Place a given key and value in the container.

Specified by:

put in interface ShortObjectMap<VType>

Returns:

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

putAll

public int putAll(ShortObjectAssociativeContainer<? extends VType> 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 ShortObjectMap<VType>

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 ShortObjectCursor<? extends VType>> iterable)

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

Specified by:

putAll in interface ShortObjectMap<VType>

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,
                  VType 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.

remove

public VType 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 ShortObjectMap<VType>

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 ShortObjectAssociativeContainer<VType>

Returns:

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

removeAll

public int removeAll(ShortObjectPredicate<? super VType> predicate)

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

Specified by:

removeAll in interface ShortObjectAssociativeContainer<VType>

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 ShortObjectAssociativeContainer<VType>

Returns:

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

get

public VType get(short key)

Specified by:

get in interface ShortObjectMap<VType>

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 VType getOrDefault(short key,
                 VType defaultValue)

Specified by:

getOrDefault in interface ShortObjectMap<VType>

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 ShortObjectAssociativeContainer<VType>

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 ShortObjectMap<VType>

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:

ShortObjectMap.indexExists(int), ShortObjectMap.indexGet(int), ShortObjectMap.indexInsert(int, short, VType), ShortObjectMap.indexReplace(int, VType)

indexExists

public boolean indexExists(int index)

Specified by:

indexExists in interface ShortObjectMap<VType>

Parameters:

index - The index of a given key, as returned from ShortObjectMap.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:

ShortObjectMap.indexOf(short)

indexGet

public VType indexGet(int index)

Returns the value associated with an existing key.

Specified by:

indexGet in interface ShortObjectMap<VType>

Parameters:

index - The index of an existing key.

Returns:

Returns the value currently associated with the key.

See Also:

ShortObjectMap.indexOf(short)

indexReplace

public VType indexReplace(int index,
                 VType newValue)

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

Specified by:

indexReplace in interface ShortObjectMap<VType>

Parameters:

index - The index of an existing key.

Returns:

Returns the previous value associated with the key.

See Also:

ShortObjectMap.indexOf(short)

indexInsert

public void indexInsert(int index,
               short key,
               VType 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 ShortObjectMap<VType>

Parameters:

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

See Also:

ShortObjectMap.indexOf(short)

clear

public void clear()

Clear all keys and values in the container.

Specified by:

clear in interface ShortObjectMap<VType>

See Also:

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

Specified by:

release in interface ShortObjectMap<VType>

See Also:

ShortObjectMap.clear()

size

public int size()

Specified by:

size in interface ShortObjectAssociativeContainer<VType>

Returns:

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

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface ShortObjectAssociativeContainer<VType>

Returns:

Return true if this hash map contains no assigned keys.

hashCode

public int hashCode()

Specified by:

hashCode in interface ShortObjectMap<VType>

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

Specified by:

equals in interface ShortObjectMap<VType>

Overrides:

equals in class java.lang.Object

equalElements

protected boolean equalElements(ShortObjectHashMap<?> other)

Return true if all keys of some other container exist in this container. Values are compared using Object.equals(Object) method.

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<ShortObjectCursor<VType>> 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 ShortObjectAssociativeContainer<VType>

Specified by:

iterator in interface java.lang.Iterable<ShortObjectCursor<VType>>

forEach

public <T extends ShortObjectProcedure<? super VType>> T forEach(T procedure)

Applies a given procedure to all keys-value pairs in this container. Returns the argument (any subclass of ShortObjectProcedure. 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 ShortObjectAssociativeContainer<VType>

forEach

public <T extends ShortObjectPredicate<? super VType>> T forEach(T predicate)

Applies a given predicate to all keys-value pairs in this container. Returns the argument (any subclass of ShortObjectPredicate. 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 ShortObjectAssociativeContainer<VType>

keys

public ShortObjectHashMap.KeysContainer keys()

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

Specified by:

keys in interface ShortObjectAssociativeContainer<VType>

values

public ObjectCollection<VType> values()

Description copied from interface: ShortObjectAssociativeContainer

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 ShortObjectAssociativeContainer<VType>

Returns:

Returns a container with all values stored in this map.

clone

public ShortObjectHashMap<VType> 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: ShortObjectMap

Visually depict the distribution of keys.

Specified by:

visualizeKeyDistribution in interface ShortObjectMap<VType>

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 <VType> ShortObjectHashMap<VType> from(short[] keys,
                                     VType[] 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,
          VType[] 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,
                                VType 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.