java.lang.Object
- org.apache.lucene.internal.hppc.CharHashSet

All Implemented Interfaces:

Cloneable, Iterable<CharCursor>, Accountable
```
public class CharHashSet
extends Object
implements Iterable<CharCursor>, Accountable, Cloneable
```
A hash set of chars, implemented using open addressing with linear probing for collision resolution.
Mostly forked and trimmed from com.carrotsearch.hppc.CharHashSet
github: https://github.com/carrotsearch/hppc release 0.10.0

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

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

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.
`protected boolean`	`hasEmptyKey`	Special treatment for the "empty slot" key marker.
`protected int`	`iterationSeed`	Seed used to ensure the hash iteration order is different from an iteration to another.
`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 int`	`resizeAt`	Expand (rehash) `keys` when `assigned` hits this value.

Fields inherited from interface org.apache.lucene.util.Accountable
NULL_ACCOUNTABLE

Constructor Summary

Constructors
Constructor	Description
`CharHashSet()`	New instance with sane defaults.
`CharHashSet(int expectedElements)`	New instance with sane defaults.
`CharHashSet(int expectedElements, double loadFactor)`	New instance with the provided defaults.
`CharHashSet(CharHashSet set)`	New instance copying elements from another set.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`add(char key)`
`int`	`addAll(char... elements)`	Adds all elements from the given list (vararg) to this set.
`int`	`addAll(Iterable<? extends CharCursor> iterable)`	Adds all elements from the given iterable to this set.
`int`	`addAll(CharHashSet set)`	Adds all elements from the given set 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()`
`CharHashSet`	`clone()`
`boolean`	`contains(char key)`
`void`	`ensureCapacity(int expectedElements)`	Ensure this container can hold at least the given number of elements without resizing its buffers.
`boolean`	`equals(Object obj)`
`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).
`void`	`indexRemove(int index)`	Removes a key at an index previously acquired from `indexOf(char)`.
`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()`
`Iterator<CharCursor>`	`iterator()`
`protected int`	`nextIterationSeed()`	Provides the next iteration seed used to build the iteration starting slot and offset increment.
`long`	`ramBytesUsed()`	Return the memory usage of this object in bytes.
`protected void`	`rehash(char[] fromKeys)`	Rehash from old buffers to new buffers.
`void`	`release()`
`boolean`	`remove(char key)`	An alias for the (preferred) `removeAll(org.apache.lucene.internal.hppc.CharHashSet)`.
`int`	`removeAll(CharHashSet other)`	Removes all keys present in a given container.
`protected void`	`shiftConflictingKeys(int gapSlot)`	Shift all the slot-conflicting keys allocated to (and including) `slot`.
`int`	`size()`
`char[]`	`toArray()`
`protected double`	`verifyLoadFactor(double loadFactor)`	Validate load factor range and return it.

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

Methods inherited from interface org.apache.lucene.util.Accountable
getChildResources

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.
  - 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.
  - iterationSeed
```
protected int iterationSeed
```
    Seed used to ensure the hash iteration order is different from an iteration to another.
- Constructor Detail
  - CharHashSet
```
public CharHashSet()
```
    New instance with sane defaults.
  - CharHashSet
```
public CharHashSet(int expectedElements)
```
    New instance with sane defaults.
    
    Parameters:
    
    expectedElements - The expected number of elements guaranteed not to cause a rehash (inclusive).
  - CharHashSet
```
public CharHashSet(int expectedElements,
                   double loadFactor)
```
    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).
  - CharHashSet
```
public CharHashSet(CharHashSet set)
```
    New instance copying elements from another set.
- Method Detail
  - add
```
public boolean add(char key)
```
  - 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(CharHashSet set)
```
    Adds all elements from the given set 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(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()
```
  - remove
```
public boolean remove(char key)
```
    An alias for the (preferred) removeAll(org.apache.lucene.internal.hppc.CharHashSet).
  - removeAll
```
public int removeAll(CharHashSet other)
```
    Removes all keys present in a given container.
    
    Returns:
    
    Returns the number of elements actually removed as a result of this call.
  - contains
```
public boolean contains(char key)
```
  - clear
```
public void clear()
```
  - release
```
public void release()
```
  - isEmpty
```
public boolean isEmpty()
```
  - ensureCapacity
```
public void ensureCapacity(int expectedElements)
```
    Ensure this container can hold at least the given number of elements without resizing its buffers.
    
    Parameters:
    
    expectedElements - The total number of elements, inclusive.
  - size
```
public int size()
```
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - equals
```
public boolean equals(Object obj)
```
    Overrides:
    
    equals in class Object
  - clone
```
public CharHashSet clone()
```
    Overrides:
    
    clone in class Object
  - iterator
```
public Iterator<CharCursor> iterator()
```
    Specified by:
    
    iterator in interface Iterable<CharCursor>
  - ramBytesUsed
```
public long ramBytesUsed()
```
    Description copied from interface: Accountable
    
    Return the memory usage of this object in bytes. Negative values are illegal.
    
    Specified by:
    
    ramBytesUsed in interface Accountable
  - nextIterationSeed
```
protected int nextIterationSeed()
```
    Provides the next iteration seed used to build the iteration starting slot and offset increment. This method does not need to be synchronized, what matters is that each thread gets a sequence of varying seeds.
  - 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 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:
    
    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:
    
    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:
    
    AssertionError - If assertions are enabled and the index does not correspond to an existing key.
    
    See Also:
    
    indexOf(char)
  - indexRemove
```
public void indexRemove(int index)
```
    Removes a key at an index previously acquired from indexOf(char).
    
    Parameters:
    
    index - The index of the key to remove, as returned from indexOf(char).
    
    Throws:
    
    AssertionError - If assertions are enabled and the index does not correspond to an existing key.
    
    See Also:
    
    indexOf(char)
  - 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

Fields inherited from interface org.apache.lucene.util.Accountable

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.lucene.util.Accountable

Methods inherited from interface java.lang.Iterable

Field Detail

keys

assigned

mask

resizeAt

hasEmptyKey

loadFactor

iterationSeed

Constructor Detail

CharHashSet

CharHashSet

CharHashSet

CharHashSet

Method Detail

add

addAll

addAll

addAll

toArray

remove

removeAll

contains

clear

release

isEmpty

ensureCapacity

size

hashCode

equals

clone

iterator

ramBytesUsed

nextIterationSeed

from

hashKey

indexOf

indexExists

indexGet

indexReplace

indexInsert

indexRemove

verifyLoadFactor

rehash

allocateBuffers

allocateThenInsertThenRehash

shiftConflictingKeys