CharHashSet

java.lang.Object
- com.carrotsearch.hppc.AbstractCharCollection
- - com.carrotsearch.hppc.CharHashSet

All Implemented Interfaces:

CharCollection, CharContainer, CharLookupContainer, CharSet, Preallocable, java.lang.Cloneable, java.lang.Iterable<CharCursor>

Direct Known Subclasses:

CharScatterSet
```
@Generated(date="2023-04-24T17:14:49+0800",
           value="KTypeHashSet.java")
public class CharHashSet
extends AbstractCharCollection
implements CharLookupContainer, CharSet, Preallocable, java.lang.Cloneable
```
A hash set of chars, implemented using using open addressing with linear probing for collision resolution.
Note: read about important differences between hash and scatter sets.

See Also:

CharScatterSet, HPPC interfaces diagram

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

protected class CharHashSet.EntryIterator
An iterator implementation for iterator().

Nested Classes
Modifier and Type	Class and Description
`protected class`	`CharHashSet.EntryIterator` An iterator implementation for `iterator()`.

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.
`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.
`char[]`	`keys` The hash 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.

Constructor Summary

Constructors
Constructor and Description
`CharHashSet()` New instance with sane defaults.
`CharHashSet(CharContainer container)` New instance copying elements from another `CharContainer`.
`CharHashSet(int expectedElements)` New instance with sane defaults.
`CharHashSet(int expectedElements, double loadFactor)` New instance with sane defaults.
`CharHashSet(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
`boolean`	`add(char key)` Adds `k` to the set.
`int`	`addAll(char... elements)` Adds all elements from the given list (vararg) to this set.
`int`	`addAll(CharContainer container)` Adds all elements from the given `CharContainer` to this set.
`int`	`addAll(java.lang.Iterable<? extends CharCursor> 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, char 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.
`CharHashSet`	`clone()`
`boolean`	`contains(char 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`	`equals(java.lang.Object obj)`
`<T extends CharPredicate> T`	`forEach(T predicate)` Applies a `predicate` to container elements as long, as the predicate returns `true`.
`<T extends CharProcedure> T`	`forEach(T procedure)` Applies a `procedure` to all container elements.
`static CharHashSet`	`from(char... elements)` Create a set from a variable number of arguments or an array of `char`.
`int`	`hashCode()`
`protected int`	`hashKey(char key)` Returns a hash code for the given key.
`boolean`	`indexExists(int index)`
`char`	`indexGet(int index)` Returns the exact value of the existing key.
`void`	`indexInsert(int index, char key)` Inserts a key for an index that is not present in the set.
`int`	`indexOf(char key)` Returns a logical "index" of a given key that can be used to speed up follow-up logic in certain scenarios (conditional logic).
`char`	`indexReplace(int index, char equivalentKey)` Replaces the existing equivalent key with the given one and returns any previous value stored for that key.
`boolean`	`isEmpty()` Shortcut for `size() == 0`.
`java.util.Iterator<CharCursor>`	`iterator()` Returns an iterator to a cursor traversing the collection.
`protected void`	`rehash(char[] fromKeys)` Rehash from old buffers to new buffers.
`void`	`release()` Removes all elements from the collection and additionally releases any internal buffers.
`boolean`	`remove(char key)` An alias for the (preferred) `removeAll(char)`.
`int`	`removeAll(char key)` Removes all occurrences of `e` from this collection.
`int`	`removeAll(CharPredicate predicate)` Removes all elements in this collection for which the given predicate returns `true`.
`private boolean`	`sameKeys(CharSet other)` 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.
`char[]`	`toArray()` Default implementation of copying to an array.
`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 com.carrotsearch.hppc.AbstractCharCollection
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.CharCollection
removeAll, retainAll, retainAll

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

- Field Detail
  - keys
```
public char[] keys
```
    The hash array holding keys.
  - assigned
```
protected int assigned
```
    The number of stored keys (assigned key slots), excluding the special "empty" key, if any.
    
    See Also:
    
    size(), hasEmptyKey
  - mask
```
protected int mask
```
    Mask for slot scans in keys.
  - 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(char), "http://issues.carrot2.org/browse/HPPC-80", "http://issues.carrot2.org/browse/HPPC-103"
  - 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
  - CharHashSet
```
public CharHashSet()
```
    New instance with sane defaults.
    
    See Also:
    
    CharHashSet(int, double, HashOrderMixingStrategy)
  - CharHashSet
```
public CharHashSet(int expectedElements)
```
    New instance with sane defaults.
    
    See Also:
    
    CharHashSet(int, double, HashOrderMixingStrategy)
  - CharHashSet
```
public CharHashSet(int expectedElements,
                   double loadFactor)
```
    New instance with sane defaults.
    
    See Also:
    
    CharHashSet(int, double, HashOrderMixingStrategy)
  - CharHashSet
```
public CharHashSet(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.
  - CharHashSet
```
public CharHashSet(CharContainer container)
```
    New instance copying elements from another CharContainer.
- Method Detail
  - add
```
public boolean add(char key)
```
    Adds k to the set.
    
    Specified by:
    
    add in interface CharSet
    
    Returns:
    
    Returns true if this element was not part of the set before. Returns false if an equal element is part of the set, and replaces the existing equal element with the argument (if keys are object types).
  - addAll
```
public final int addAll(char... 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).
  - addAll
```
public int addAll(CharContainer container)
```
    Adds all elements from the given CharContainer to this set.
    
    Returns:
    
    Returns the number of elements actually added as a result of this call (not previously present in the set).
  - addAll
```
public int addAll(java.lang.Iterable<? extends CharCursor> iterable)
```
    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).
  - toArray
```
public char[] toArray()
```
    Default implementation of copying to an array.
    
    Specified by:
    
    toArray in interface CharContainer
    
    Overrides:
    
    toArray in class AbstractCharCollection
  - remove
```
public boolean remove(char key)
```
    An alias for the (preferred) removeAll(char).
  - removeAll
```
public int removeAll(char key)
```
    Removes all occurrences of e from this collection.
    
    Specified by:
    
    removeAll in interface CharCollection
    
    Parameters:
    
    key - Element to be removed from this collection, if present.
    
    Returns:
    
    The number of removed elements as a result of this call.
  - removeAll
```
public int removeAll(CharPredicate predicate)
```
    Removes all elements in this collection for which the given predicate returns true.
    
    Specified by:
    
    removeAll in interface CharCollection
    
    Returns:
    
    Returns the number of removed elements.
  - contains
```
public boolean contains(char 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 interface CharContainer
    
    Specified by:
    
    contains in interface CharLookupContainer
    
    Returns:
    
    Returns true if this container has an element equal to e.
  - clear
```
public void clear()
```
    Removes all elements from this collection.
    
    Specified by:
    
    clear in interface CharCollection
    
    See Also:
    
    CharCollection.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 CharCollection.clear() should be a better alternative since it'll avoid reallocation.
    
    Specified by:
    
    release in interface CharCollection
    
    See Also:
    
    CharCollection.clear()
  - isEmpty
```
public boolean isEmpty()
```
    Shortcut for size() == 0.
    
    Specified by:
    
    isEmpty in interface CharContainer
  - 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 interface Preallocable
    
    Parameters:
    
    expectedElements - The total number of elements, inclusive.
  - size
```
public int size()
```
    Return the current number of elements in this container. The time for calculating the container's size may take O(n) time, although implementing classes should try to maintain the current size and return in constant time.
    
    Specified by:
    
    size in interface CharContainer
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - equals
```
public boolean equals(java.lang.Object obj)
```
    Overrides:
    
    equals in class java.lang.Object
  - sameKeys
```
private boolean sameKeys(CharSet other)
```
    Return true if all keys of some other container exist in this container.
  - clone
```
public CharHashSet clone()
```
    Overrides:
    
    clone in class java.lang.Object
  - iterator
```
public java.util.Iterator<CharCursor> 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 (CharCursor<char> c : container) {
   System.out.println("index=" + c.index + " value=" + c.value);
 }
 
```
    Specified by:
    
    iterator in interface CharContainer
    
    Specified by:
    
    iterator in interface java.lang.Iterable<CharCursor>
  - forEach
```
public <T extends CharProcedure> T forEach(T procedure)
```
    Applies a procedure to all container elements. Returns the argument (any subclass of CharProcedure. 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 interface CharContainer
  - forEach
```
public <T extends CharPredicate> T forEach(T predicate)
```
    Applies a predicate to container elements as long, as the predicate returns true. The iteration is interrupted otherwise.
    
    Specified by:
    
    forEach in interface CharContainer
  - from
```
public static CharHashSet from(char... elements)
```
    Create a set from a variable number of arguments or an array of char. The elements are copied from the argument to the internal buffer.
  - hashKey
```
protected int hashKey(char 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.
  - indexOf
```
public int indexOf(char 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:
    
    indexExists(int), indexGet(int), indexInsert(int, char), indexReplace(int, char)
  - indexExists
```
public boolean indexExists(int index)
```
    Parameters:
    
    index - The index of a given key, as returned from indexOf(char).
    
    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:
    
    indexOf(char)
  - indexGet
```
public char 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:
    
    java.lang.AssertionError - If assertions are enabled and the index does not correspond to an existing key.
    
    See Also:
    
    indexOf(char)
  - indexReplace
```
public char indexReplace(int index,
                         char 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:
    
    java.lang.AssertionError - If assertions are enabled and the index does not correspond to an existing key.
    
    See Also:
    
    indexOf(char)
  - indexInsert
```
public void indexInsert(int index,
                        char 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 from indexOf(char).
    
    Throws:
    
    java.lang.AssertionError - If assertions are enabled and the index does not correspond to an existing key.
    
    See Also:
    
    indexOf(char)
  - visualizeKeyDistribution
```
public java.lang.String visualizeKeyDistribution(int characters)
```
    Description copied from interface: CharSet
    
    Visually depict the distribution of keys.
    
    Specified by:
    
    visualizeKeyDistribution in interface CharSet
    
    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.
  - 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(char[] 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,
                                            char 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.

Class CharHashSet

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.carrotsearch.hppc.AbstractCharCollection

Methods inherited from class java.lang.Object

Methods inherited from interface com.carrotsearch.hppc.CharCollection

Methods inherited from interface java.lang.Iterable

Field Detail

keys

assigned

mask

keyMixer

resizeAt

hasEmptyKey

loadFactor

orderMixer

Constructor Detail

CharHashSet

CharHashSet

CharHashSet

CharHashSet

CharHashSet

Method Detail

add

addAll

addAll

addAll

toArray

remove

removeAll

removeAll

contains

clear

release

isEmpty

ensureCapacity

size

hashCode

equals

sameKeys

clone

iterator

forEach

forEach

from

hashKey

indexOf

indexExists

indexGet

indexReplace

indexInsert

visualizeKeyDistribution

verifyLoadFactor

rehash

allocateBuffers

allocateThenInsertThenRehash

shiftConflictingKeys