Package com.github.tommyettinger.ds

Class CaseInsensitiveSet

java.lang.Object

com.github.tommyettinger.ds.ObjectSet<CharSequence>

com.github.tommyettinger.ds.CaseInsensitiveSet

All Implemented Interfaces:

EnhancedCollection<CharSequence>, Iterable<CharSequence>, Collection<CharSequence>, Set<CharSequence>

public class CaseInsensitiveSet
extends ObjectSet<CharSequence>

A custom variant on ObjectSet that always uses CharSequence keys and compares them as case-insensitive. This uses a fairly complex, quite-optimized hashing function because it needs to hash CharSequences rather often, and to do so ignoring case means String.hashCode() won't work, plus not all CharSequences implement hashCode() themselves (such as StringBuilder). User code similar to this can often get away with a simple polynomial hash (the typical Java kind, used by String and Arrays), or if more speed is needed, one with some of these optimizations by Richard Startin. If you don't want to write or benchmark a hash function (which is quite understandable), Utilities.hashCodeIgnoreCase(CharSequence) can get a case-insensitive hash of any CharSequence, as a long. It does this without allocating new Strings all over, where many case-insensitive algorithms do allocate quite a lot, but it does this by handling case incorrectly for the Georgian alphabet. If I see Georgian text in-the-wild, I may reconsider, but I don't think that particular alphabet is in widespread use. There's also Utilities.equalsIgnoreCase(CharSequence, CharSequence) for equality comparisons that are similarly case-insensitive, except for Georgian.
This is very similar to FilteredStringSet when its editor is Character.toUpperCase(char) or Casing.caseUp(char). FilteredStringSet works with Strings rather than CharSequences, which may be more convenient, and allows filtering some characters out of hashing and equality comparisons. If you want a case-insensitive set that ignores any non-letter characters in a String, then CaseInsensitiveSet won't do, but new FilteredStringSet<>(CharPredicates.IS_LETTER, Casing::caseUp will work. Note that GWT only handles Character.isLetter(char) for ASCII letters; CharPredicates in this library provides cross-platform predicates that use CharBitSet to store their data, and the library RegExodus offers replacements in Category for other Unicode categories, such as upper-case letters, currency symbols, decimal digits, and so on.

Nested Class Summary

Nested classes/interfaces inherited from class com.github.tommyettinger.ds.ObjectSet

ObjectSet.ObjectSetIterator<T>

Field Summary

Fields inherited from class com.github.tommyettinger.ds.ObjectSet

hashMultiplier, iterator1, iterator2, keyTable, loadFactor, mask, shift, size, threshold

Constructor Summary

Constructors

Constructor	Description
CaseInsensitiveSet()	Creates a new set with an initial capacity of Utilities.getDefaultTableCapacity() and a load factor of Utilities.getDefaultLoadFactor().
CaseInsensitiveSet(int initialCapacity)	Creates a new set with the specified initial capacity a load factor of Utilities.getDefaultLoadFactor().
CaseInsensitiveSet(int initialCapacity, float loadFactor)	Creates a new set with the specified initial capacity and load factor.
CaseInsensitiveSet(CaseInsensitiveSet set)	Creates a new set that contains all distinct elements in set.
CaseInsensitiveSet(ObjectSet<? extends CharSequence> set)	Creates a new set identical to the specified set.
CaseInsensitiveSet(CharSequence[] array)	Creates a new set containing all the items in the given array.
CaseInsensitiveSet(CharSequence[] array, int offset, int length)	Creates a new set using length items from the given array, starting at offset (inclusive).
CaseInsensitiveSet(Collection<? extends CharSequence> coll)	Creates a new set that contains all distinct elements in coll.
CaseInsensitiveSet(Iterator<? extends CharSequence> coll)	Creates a new instance containing the items in the specified iterator.

Method Summary

Modifier and Type	Method	Description
protected boolean	equate(Object left, Object right)	Compares the objects left and right, which are usually keys, for equality, returning true if they are considered equal.
int	hashCode()
static CaseInsensitiveSet	parse(String str, String delimiter)	Calls ObjectSet.parse(String, String, PartialParser, boolean) with brackets set to false.
static CaseInsensitiveSet	parse(String str, String delimiter, boolean brackets)	Creates a new collection and fills it by calling EnhancedCollection.addLegible(String, String, PartialParser, int, int) on either all of str (if brackets is false) or str without its first and last chars (if brackets is true).
static CaseInsensitiveSet	parse(String str, String delimiter, int offset, int length)	Creates a new collection and fills it by calling EnhancedCollection.addLegible(String, String, PartialParser, int, int) with the given five parameters as-is.
protected int	place(Object item)	Returns an index >= 0 and <= ObjectSet.mask for the specified item, mixed.
protected void	resize(int newSize)
static CaseInsensitiveSet	with()	Constructs an empty set.
static CaseInsensitiveSet	with(CharSequence item)	Creates a new CaseInsensitiveSet that holds only the given item, but can be resized.
static CaseInsensitiveSet	with(CharSequence... varargs)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2, CharSequence item3)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2, CharSequence item3, CharSequence item4)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2, CharSequence item3, CharSequence item4, CharSequence item5)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2, CharSequence item3, CharSequence item4, CharSequence item5, CharSequence item6)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.
static CaseInsensitiveSet	with(CharSequence item0, CharSequence item1, CharSequence item2, CharSequence item3, CharSequence item4, CharSequence item5, CharSequence item6, CharSequence item7)	Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Methods inherited from class com.github.tommyettinger.ds.ObjectSet

add, addAll, addAll, addAll, addAll, addResize, appendTo, clear, clear, contains, containsAll, containsAll, containsAll, containsAny, containsAny, containsAnyIterable, ensureCapacity, equals, first, get, getHashMultiplier, getLoadFactor, getTableSize, isEmpty, iterator, locateKey, notEmpty, parse, parse, parse, remove, removeAll, removeAll, removeAll, retainAll, setHashMultiplier, setLoadFactor, shrink, size, toArray, toArray, toString, truncate, with, with, with, with, with, with, with, with, with

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface com.github.tommyettinger.ds.EnhancedCollection

add, add, add, addAll, addAllIterable, addLegible, addLegible, addVarargs, appendTo, appendTo, containsAll, containsAllIterable, containsAny, removeAll, removeAllIterable, removeEach, removeEach, removeEach, removeEachIterable, toString, toString, toString

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

spliterator

Constructor Details

CaseInsensitiveSet

public CaseInsensitiveSet()

Creates a new set with an initial capacity of Utilities.getDefaultTableCapacity() and a load factor of Utilities.getDefaultLoadFactor().

CaseInsensitiveSet

public CaseInsensitiveSet(int initialCapacity)

Creates a new set with the specified initial capacity a load factor of Utilities.getDefaultLoadFactor(). This set will hold initialCapacity items before growing the backing table.

Parameters:

initialCapacity - If not a power of two, it is increased to the next nearest power of two.

CaseInsensitiveSet

public CaseInsensitiveSet(int initialCapacity,
 float loadFactor)

Creates a new set with the specified initial capacity and load factor. This set will hold initialCapacity items before growing the backing table.

Parameters:

initialCapacity - If not a power of two, it is increased to the next nearest power of two.

loadFactor - what fraction of the capacity can be filled before this has to resize; 0 < loadFactor <= 1

CaseInsensitiveSet

public CaseInsensitiveSet(Iterator<? extends CharSequence> coll)

Creates a new instance containing the items in the specified iterator.

Parameters:

coll - an iterator that will have its remaining contents added to this

CaseInsensitiveSet

public CaseInsensitiveSet(ObjectSet<? extends CharSequence> set)

Creates a new set identical to the specified set.

Parameters:

set - an ObjectSet or one of its subclasses

CaseInsensitiveSet

public CaseInsensitiveSet(Collection<? extends CharSequence> coll)

Creates a new set that contains all distinct elements in coll.

Parameters:

coll - a Collection implementation, such as an ObjectList

CaseInsensitiveSet

public CaseInsensitiveSet(CharSequence[] array,
 int offset,
 int length)

Creates a new set using length items from the given array, starting at offset (inclusive).

Parameters:

array - an array to draw items from

offset - the first index in array to draw an item from

length - how many items to take from array; bounds-checking is the responsibility of the using code

CaseInsensitiveSet

public CaseInsensitiveSet(CharSequence[] array)

Creates a new set containing all the items in the given array.

Parameters:

array - an array that will be used in full, except for duplicate items

CaseInsensitiveSet

public CaseInsensitiveSet(CaseInsensitiveSet set)

Creates a new set that contains all distinct elements in set.

Parameters:

set - another CaseInsensitiveSet

Method Details

place

protected int place(Object item)

Description copied from class: ObjectSet

Returns an index >= 0 and <= ObjectSet.mask for the specified item, mixed.

Overrides:

place in class ObjectSet<CharSequence>

Parameters:

item - a non-null Object; its hashCode() method should be used by most implementations

Returns:

an index between 0 and ObjectSet.mask (both inclusive)

equate

protected boolean equate(Object left,
 Object right)

Description copied from class: ObjectSet

Compares the objects left and right, which are usually keys, for equality, returning true if they are considered equal. This is used by the rest of this class to determine whether two keys are considered equal. Normally, this returns left.equals(right), but subclasses can override it to use reference equality, fuzzy equality, deep array equality, or any other custom definition of equality. Usually, ObjectSet.place(Object) is also overridden if this method is.

Overrides:

equate in class ObjectSet<CharSequence>

Parameters:

left - must be non-null; typically a key being compared, but not necessarily

right - may be null; typically a key being compared, but can often be null for an empty key slot, or some other type

Returns:

true if left and right are considered equal for the purposes of this class

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection<CharSequence>

Specified by:

hashCode in interface Set<CharSequence>

Overrides:

hashCode in class ObjectSet<CharSequence>

resize

protected void resize(int newSize)

Overrides:

resize in class ObjectSet<CharSequence>

with

public static CaseInsensitiveSet with()

Constructs an empty set. This is usually less useful than just using the constructor, but can be handy in some code-generation scenarios when you don't know how many arguments you will have.

Returns:

a new set containing nothing

with

public static CaseInsensitiveSet with(CharSequence item)

Creates a new CaseInsensitiveSet that holds only the given item, but can be resized.

Parameters:

item - one CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given item

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2,
 CharSequence item3)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

item3 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2,
 CharSequence item3,
 CharSequence item4)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

item3 - a CharSequence item

item4 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2,
 CharSequence item3,
 CharSequence item4,
 CharSequence item5)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

item3 - a CharSequence item

item4 - a CharSequence item

item5 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2,
 CharSequence item3,
 CharSequence item4,
 CharSequence item5,
 CharSequence item6)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

item3 - a CharSequence item

item4 - a CharSequence item

item5 - a CharSequence item

item6 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence item0,
 CharSequence item1,
 CharSequence item2,
 CharSequence item3,
 CharSequence item4,
 CharSequence item5,
 CharSequence item6,
 CharSequence item7)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized.

Parameters:

item0 - a CharSequence item

item1 - a CharSequence item

item2 - a CharSequence item

item3 - a CharSequence item

item4 - a CharSequence item

item5 - a CharSequence item

item6 - a CharSequence item

Returns:

a new CaseInsensitiveSet that holds the given items

with

public static CaseInsensitiveSet with(CharSequence... varargs)

Creates a new CaseInsensitiveSet that holds only the given items, but can be resized. This overload will only be used when varargs are used and there are 9 or more arguments.

Parameters:

varargs - a CharSequence varargs or CharSequence array; remember that varargs allocate

Returns:

a new CaseInsensitiveSet that holds the given items

parse

public static CaseInsensitiveSet parse(String str,
 String delimiter)

Calls ObjectSet.parse(String, String, PartialParser, boolean) with brackets set to false.

Parameters:

str - a String that will be parsed in full

delimiter - the delimiter between items in str

Returns:

a new collection parsed from str

parse

public static CaseInsensitiveSet parse(String str,
 String delimiter,
 boolean brackets)

Creates a new collection and fills it by calling EnhancedCollection.addLegible(String, String, PartialParser, int, int) on either all of str (if brackets is false) or str without its first and last chars (if brackets is true). Each item is expected to be separated by delimiter.

Parameters:

str - a String that will be parsed in full (depending on brackets)

delimiter - the delimiter between items in str

brackets - if true, the first and last chars in str will be ignored

Returns:

a new collection parsed from str

parse

public static CaseInsensitiveSet parse(String str,
 String delimiter,
 int offset,
 int length)

Creates a new collection and fills it by calling EnhancedCollection.addLegible(String, String, PartialParser, int, int) with the given five parameters as-is.

Parameters:

str - a String that will have the given section parsed

delimiter - the delimiter between items in str

offset - the first position to parse in str, inclusive

length - how many chars to parse, starting from offset

Returns:

a new collection parsed from str