Package com.carrotsearch.hppc
Class ByteHashSet
java.lang.Object
com.carrotsearch.hppc.AbstractByteCollection
com.carrotsearch.hppc.ByteHashSet
- All Implemented Interfaces:
ByteCollection
,ByteContainer
,ByteLookupContainer
,ByteSet
,Preallocable
,Cloneable
,Iterable<ByteCursor>
- Direct Known Subclasses:
ByteScatterSet
@Generated(date="2023-10-26T04:33:09+0000",
value="KTypeHashSet.java")
public class ByteHashSet
extends AbstractByteCollection
implements ByteLookupContainer, ByteSet, Preallocable, Cloneable
A hash set of
byte
s, implemented using using open addressing
with linear probing for collision resolution.
Note: read about important differences between hash and scatter sets.
- See Also:
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprotected final class
An iterator implementation foriterator()
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected int
The number of stored keys (assigned key slots), excluding the special "empty" key, if any.protected boolean
Special treatment for the "empty slot" key marker.protected int
We perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.byte[]
The hash array holding keys.protected double
The load factor forkeys
.protected int
Mask for slot scans inkeys
.protected HashOrderMixingStrategy
Per-instance hash order mixing strategy.protected int
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Constructor Summary
ConstructorsConstructorDescriptionNew instance with sane defaults.ByteHashSet
(int expectedElements) New instance with sane defaults.ByteHashSet
(int expectedElements, double loadFactor) New instance with sane defaults.ByteHashSet
(int expectedElements, double loadFactor, HashOrderMixingStrategy orderMixer) New instance with the provided defaults.ByteHashSet
(ByteContainer container) New instance copying elements from anotherByteContainer
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Method Summary
Modifier and TypeMethodDescriptionboolean
add
(byte key) Addsk
to the set.final int
addAll
(byte... elements) Adds all elements from the given list (vararg) to this set.int
addAll
(ByteContainer container) Adds all elements from the givenByteContainer
to this set.int
addAll
(Iterable<? extends ByteCursor> iterable) Adds all elements from the given iterable to this set.protected void
allocateBuffers
(int arraySize) Allocate new internal buffers.protected void
allocateThenInsertThenRehash
(int slot, byte pendingKey) This method is invoked when there is a new key to be inserted into the buffer but there is not enough empty slots to do so.void
clear()
Removes all elements from this collection.clone()
boolean
contains
(byte key) Lookup a given element in the container.void
ensureCapacity
(int expectedElements) Ensure this container can hold at least the given number of elements without resizing its buffers.boolean
<T extends ByteProcedure>
TforEach
(T procedure) Applies aprocedure
to all container elements.static ByteHashSet
from
(byte... elements) Create a set from a variable number of arguments or an array ofbyte
.int
hashCode()
protected int
hashKey
(byte key) Returns a hash code for the given key.boolean
indexExists
(int index) byte
indexGet
(int index) Returns the exact value of the existing key.void
indexInsert
(int index, byte key) Inserts a key for an index that is not present in the set.int
indexOf
(byte key) Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).byte
indexReplace
(int index, byte equivalentKey) Replaces the existing equivalent key with the given one and returns any previous value stored for that key.boolean
isEmpty()
Shortcut forsize() == 0
.iterator()
Returns an iterator to a cursor traversing the collection.protected void
rehash
(byte[] fromKeys) Rehash from old buffers to new buffers.void
release()
Removes all elements from the collection and additionally releases any internal buffers.boolean
remove
(byte key) An alias for the (preferred)removeAll(byte)
.int
removeAll
(byte key) Removes all occurrences ofe
from this collection.int
removeAll
(BytePredicate predicate) Removes all elements in this collection for which the given predicate returnstrue
.private boolean
Return true if all keys of some other container exist in this container.protected void
shiftConflictingKeys
(int gapSlot) Shift all the slot-conflicting keys allocated to (and including)slot
.int
size()
Return the current number of elements in this container.byte[]
toArray()
Default implementation of copying to an array.protected double
verifyLoadFactor
(double loadFactor) Validate load factor range and return it.visualizeKeyDistribution
(int characters) Visually depict the distribution of keys.Methods inherited from class com.carrotsearch.hppc.AbstractByteCollection
removeAll, retainAll, retainAll, toString
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
Methods inherited from interface com.carrotsearch.hppc.ByteCollection
removeAll, retainAll, retainAll
Methods inherited from interface java.lang.Iterable
forEach, spliterator
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Field Details
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keys
public byte[] keysThe hash array holding keys. -
assigned
protected int assignedThe number of stored keys (assigned key slots), excluding the special "empty" key, if any.- See Also:
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mask
protected int maskMask for slot scans inkeys
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keyMixer
protected int keyMixerWe perturb hash values with a container-unique seed to avoid problems with nearly-sorted-by-hash values on iterations.- See Also:
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hashKey(byte)
- "http://issues.carrot2.org/browse/HPPC-80"
- "http://issues.carrot2.org/browse/HPPC-103"
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resizeAt
protected int resizeAt -
hasEmptyKey
protected boolean hasEmptyKeySpecial treatment for the "empty slot" key marker. -
loadFactor
protected double loadFactorThe load factor forkeys
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orderMixer
Per-instance hash order mixing strategy.- See Also:
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Constructor Details
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ByteHashSet
public ByteHashSet()New instance with sane defaults. -
ByteHashSet
public ByteHashSet(int expectedElements) New instance with sane defaults. -
ByteHashSet
public ByteHashSet(int expectedElements, double loadFactor) New instance with sane defaults. -
ByteHashSet
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 byverifyLoadFactor(double)
.orderMixer
- Hash key order mixing strategy. SeeHashOrderMixing
for predefined implementations. Use constant mixers only if you understand the potential consequences.
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ByteHashSet
New instance copying elements from anotherByteContainer
.
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Method Details
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add
public boolean add(byte key) Addsk
to the set. -
addAll
public final int addAll(byte... elements) Adds all elements from the given list (vararg) to this set.- Returns:
- Returns the number of elements actually added as a result of this call (not previously present in the set).
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addAll
Adds all elements from the givenByteContainer
to this set.- Returns:
- Returns the number of elements actually added as a result of this call (not previously present in the set).
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addAll
Adds all elements from the given iterable to this set.- Returns:
- Returns the number of elements actually added as a result of this call (not previously present in the set).
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toArray
public byte[] toArray()Default implementation of copying to an array.- Specified by:
toArray
in interfaceByteContainer
- Overrides:
toArray
in classAbstractByteCollection
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remove
public boolean remove(byte key) An alias for the (preferred)removeAll(byte)
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removeAll
public int removeAll(byte key) Removes all occurrences ofe
from this collection.- Specified by:
removeAll
in interfaceByteCollection
- Parameters:
key
- Element to be removed from this collection, if present.- Returns:
- The number of removed elements as a result of this call.
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removeAll
Removes all elements in this collection for which the given predicate returnstrue
.- Specified by:
removeAll
in interfaceByteCollection
- Returns:
- Returns the number of removed elements.
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contains
public boolean contains(byte key) Lookup a given element in the container. This operation has no speed guarantees (may be linear with respect to the size of this container).- Specified by:
contains
in interfaceByteContainer
- Specified by:
contains
in interfaceByteLookupContainer
- Returns:
- Returns
true
if this container has an element equal toe
.
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clear
public void clear()Removes all elements from this collection.- Specified by:
clear
in interfaceByteCollection
- See Also:
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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 simpleByteCollection.clear()
should be a better alternative since it'll avoid reallocation.- Specified by:
release
in interfaceByteCollection
- See Also:
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isEmpty
public boolean isEmpty()Shortcut forsize() == 0
.- Specified by:
isEmpty
in interfaceByteContainer
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ensureCapacity
public void ensureCapacity(int expectedElements) Ensure this container can hold at least the given number of elements without resizing its buffers.- Specified by:
ensureCapacity
in interfacePreallocable
- Parameters:
expectedElements
- The total number of elements, inclusive.
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size
public int size()Return the current number of elements in this container. The time for calculating the container's size may takeO(n)
time, although implementing classes should try to maintain the current size and return in constant time.- Specified by:
size
in interfaceByteContainer
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hashCode
public int hashCode() -
equals
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sameKeys
Return true if all keys of some other container exist in this container. -
clone
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iterator
Returns an iterator to a cursor traversing the collection. The order of traversal is not defined. More than one cursor may be active at a time. The behavior of iterators is undefined if structural changes are made to the underlying collection.The iterator is implemented as a cursor and it returns the same cursor instance on every call to
Iterator.next()
(to avoid boxing of primitive types). To read the current list's value (or index in the list) use the cursor's public fields. An example is shown below.for (ByteCursor<byte> c : container) { System.out.println("index=" + c.index + " value=" + c.value); }
- Specified by:
iterator
in interfaceByteContainer
- Specified by:
iterator
in interfaceIterable<ByteCursor>
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forEach
Applies aprocedure
to all container elements. Returns the argument (any subclass ofByteProcedure
. 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 (IntContainer):int count = container.forEach(new IntProcedure() { int count; // this is a field declaration in an anonymous class. public void apply(int value) { count++; } }).count;
- Specified by:
forEach
in interfaceByteContainer
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forEach
Applies apredicate
to container elements as long, as the predicate returnstrue
. The iteration is interrupted otherwise.- Specified by:
forEach
in interfaceByteContainer
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from
Create a set from a variable number of arguments or an array ofbyte
. The elements are copied from the argument to the internal buffer. -
hashKey
protected int hashKey(byte key) Returns a hash code for the given key. The default implementation mixes the hash of the key withkeyMixer
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. -
indexOf
public int indexOf(byte key) Returns a logical "index" of a given key that can be used to speed up follow-up logic 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 modifications (it will not be affected by read-only operations).- Parameters:
key
- The key to locate in the set.- Returns:
- A non-negative value of the logical "index" of the key in the set or a negative value if the key did not exist.
- See Also:
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indexExists
public boolean indexExists(int index) - Parameters:
index
- The index of a given key, as returned fromindexOf(byte)
.- 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:
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indexGet
public byte indexGet(int index) Returns the exact value of the existing key. This method makes sense for sets of objects which define custom key-equality relationship.- Parameters:
index
- The index of an existing key.- Returns:
- Returns the equivalent key currently stored in the set.
- Throws:
AssertionError
- If assertions are enabled and the index does not correspond to an existing key.- See Also:
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indexReplace
public byte indexReplace(int index, byte equivalentKey) Replaces the existing equivalent key with the given one and returns any previous value stored for that key.- Parameters:
index
- The index of an existing key.equivalentKey
- The key to put in the set as a replacement. Must be equivalent to the key currently stored at the provided index.- Returns:
- Returns the previous key stored in the set.
- Throws:
AssertionError
- If assertions are enabled and the index does not correspond to an existing key.- See Also:
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indexInsert
public void indexInsert(int index, byte key) Inserts a key for an index that is not present in the set. This method may help in avoiding double recalculation of the key's hash.- Parameters:
index
- The index of a previously non-existing key, as returned fromindexOf(byte)
.- Throws:
AssertionError
- If assertions are enabled and the index does not correspond to an existing key.- See Also:
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visualizeKeyDistribution
Description copied from interface:ByteSet
Visually depict the distribution of keys.- Specified by:
visualizeKeyDistribution
in interfaceByteSet
- 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.
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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(byte[] fromKeys) 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, byte pendingKey) This method is invoked when there is a new key to be inserted into the buffer 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 allocated to (and including)slot
.
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