Package org.apache.lucene.internal.hppc
Class CharHashSet
- 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 ofchars, 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 classCharHashSet.EntryIteratorAn iterator implementation foriterator().
-
Field Summary
Fields Modifier and Type Field Description protected intassignedThe number of stored keys (assigned key slots), excluding the special "empty" key, if any.protected booleanhasEmptyKeySpecial treatment for the "empty slot" key marker.protected intiterationSeedSeed used to ensure the hash iteration order is different from an iteration to another.char[]keysThe hash array holding keys.protected doubleloadFactorThe load factor forkeys.protected intmaskMask for slot scans inkeys.protected intresizeAt-
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 booleanadd(char key)intaddAll(char... elements)Adds all elements from the given list (vararg) to this set.intaddAll(Iterable<? extends CharCursor> iterable)Adds all elements from the given iterable to this set.intaddAll(CharHashSet set)Adds all elements from the given set to this set.protected voidallocateBuffers(int arraySize)Allocate new internal buffers.protected voidallocateThenInsertThenRehash(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.voidclear()CharHashSetclone()booleancontains(char key)voidensureCapacity(int expectedElements)Ensure this container can hold at least the given number of elements without resizing its buffers.booleanequals(Object obj)static CharHashSetfrom(char... elements)Create a set from a variable number of arguments or an array ofchar.inthashCode()protected inthashKey(char key)Returns a hash code for the given key.booleanindexExists(int index)charindexGet(int index)Returns the exact value of the existing key.voidindexInsert(int index, char key)Inserts a key for an index that is not present in the set.intindexOf(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).voidindexRemove(int index)Removes a key at an index previously acquired fromindexOf(char).charindexReplace(int index, char equivalentKey)Replaces the existing equivalent key with the given one and returns any previous value stored for that key.booleanisEmpty()Iterator<CharCursor>iterator()protected intnextIterationSeed()Provides the next iteration seed used to build the iteration starting slot and offset increment.longramBytesUsed()Return the memory usage of this object in bytes.protected voidrehash(char[] fromKeys)Rehash from old buffers to new buffers.voidrelease()booleanremove(char key)An alias for the (preferred)removeAll(org.apache.lucene.internal.hppc.CharHashSet).intremoveAll(CharHashSet other)Removes all keys present in a given container.protected voidshiftConflictingKeys(int gapSlot)Shift all the slot-conflicting keys allocated to (and including)slot.intsize()char[]toArray()protected doubleverifyLoadFactor(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 inkeys.
-
resizeAt
protected int resizeAt
-
hasEmptyKey
protected boolean hasEmptyKey
Special treatment for the "empty slot" key marker.
-
loadFactor
protected double loadFactor
The load factor forkeys.
-
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 byverifyLoadFactor(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()
-
clone
public CharHashSet clone()
-
iterator
public Iterator<CharCursor> iterator()
- Specified by:
iteratorin interfaceIterable<CharCursor>
-
ramBytesUsed
public long ramBytesUsed()
Description copied from interface:AccountableReturn the memory usage of this object in bytes. Negative values are illegal.- Specified by:
ramBytesUsedin interfaceAccountable
-
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 ofchar. 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 fromindexOf(char).- Returns:
- Returns
trueif 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 fromindexOf(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 fromindexOf(char).- Parameters:
index- The index of the key to remove, as returned fromindexOf(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.
-
-