Package com.github.tommyettinger.ds

Class IdentityOrderedSet<T>

java.lang.Object

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

com.github.tommyettinger.ds.ObjectOrderedSet<T>

com.github.tommyettinger.ds.IdentityOrderedSet<T>

All Implemented Interfaces:

Arrangeable, EnhancedCollection<T>, Ordered<T>, Iterable<T>, Collection<T>, Set<T>

public class IdentityOrderedSet<T>
extends ObjectOrderedSet<T>

A variant on ObjectOrderedSet that compares items by identity (using ==) instead of equality (using equals()). It also hashes with System.identityHashCode(Object) instead of calling the hashCode() of an item. This can be useful in some cases where items may have invalid Object.equals(Object) and/or Object.hashCode() implementations, or if items could be very large (making a hashCode() that uses all the parts of the item slow). Oddly, System.identityHashCode(Object) tends to be slower than the hashCode() for most small items, because an explicitly-written hashCode() typically doesn't need to do anything concurrently, but identityHashCode() needs to (concurrently) modify an internal JVM variable that ensures the results are unique, and that requires the JVM to do lots of extra work whenever identityHashCode() is called. Despite that, identityHashCode() doesn't depend on the quantity of variables in the item, so identityHashCode() gets relatively faster for larger items. The equals() method used by ObjectOrderedSet also tends to slow down for large items, relative to the constant-time == this uses.
This can potentially be useful for tracking references to ensure they are all unique by identity, such as to avoid referential cycles. You might prefer this to IdentitySet if you need to ensure fast iteration or want access by index.

Nested Class Summary

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

ObjectOrderedSet.ObjectOrderedSetIterator<K>

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

ObjectSet.ObjectSetIterator<T>

Nested classes/interfaces inherited from interface com.github.tommyettinger.ds.Arrangeable

Arrangeable.ArrangeableList<T>

Nested classes/interfaces inherited from interface com.github.tommyettinger.ds.Ordered

Ordered.OfBoolean, Ordered.OfByte, Ordered.OfChar, Ordered.OfDouble, Ordered.OfFloat, Ordered.OfInt, Ordered.OfLong, Ordered.OfShort

Field Summary

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

items

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

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

Constructor Summary

Constructors

Constructor	Description
IdentityOrderedSet()
IdentityOrderedSet(int initialCapacity)
IdentityOrderedSet(int initialCapacity, float loadFactor)
IdentityOrderedSet(int initialCapacity, float loadFactor, OrderType type)
IdentityOrderedSet(int initialCapacity, OrderType type)
IdentityOrderedSet(ObjectOrderedSet<? extends T> set)
IdentityOrderedSet(ObjectOrderedSet<? extends T> set, OrderType type)
IdentityOrderedSet(Ordered<T> other, int offset, int count)
IdentityOrderedSet(Ordered<T> other, int offset, int count, OrderType type)
IdentityOrderedSet(OrderType type)
IdentityOrderedSet(Collection<? extends T> coll)
IdentityOrderedSet(Collection<? extends T> coll, OrderType type)
IdentityOrderedSet(Iterator<? extends T> coll)	Creates a new instance containing the items in the specified iterator.
IdentityOrderedSet(Iterator<? extends T> coll, OrderType type)	Creates a new instance containing the items in the specified iterator.
IdentityOrderedSet(T[] array)
IdentityOrderedSet(T[] array, int offset, int length)
IdentityOrderedSet(T[] array, int offset, int length, OrderType type)
IdentityOrderedSet(T[] array, OrderType type)

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	getHashMultiplier()	Effectively does nothing here because the hashMultiplier is not used by identity hashing.
int	hashCode()
static <T> IdentityOrderedSet<T>	parse(String str, String delimiter, PartialParser<T> parser)	Calls parse(String, String, PartialParser, boolean) with brackets set to false.
static <T> IdentityOrderedSet<T>	parse(String str, String delimiter, PartialParser<T> parser, 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 <T> IdentityOrderedSet<T>	parse(String str, String delimiter, PartialParser<T> parser, 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.
void	setHashMultiplier(int hashMultiplier)	Effectively does nothing here because the hashMultiplier is not used by identity hashing.
static <T> IdentityOrderedSet<T>	with()	Constructs an empty set given the type as a generic type argument.
static <T> IdentityOrderedSet<T>	with(T item)	Creates a new IdentityOrderedSet that holds only the given item, but can be resized.
static <T> IdentityOrderedSet<T>	with(T... varargs)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2, T item3)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2, T item3, T item4)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2, T item3, T item4, T item5)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2, T item3, T item4, T item5, T item6)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.
static <T> IdentityOrderedSet<T>	with(T item0, T item1, T item2, T item3, T item4, T item5, T item6, T item7)	Creates a new IdentityOrderedSet that holds only the given items, but can be resized.

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

add, add, addAll, addAll, alter, alterAt, clear, clear, ensureCapacity, first, getAt, iterator, order, remove, removeAt, removeRange, sort, sort, toString, toString, truncate

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

addAll, addAll, addAll, addAll, addResize, appendTo, contains, containsAll, containsAll, containsAll, containsAny, containsAny, containsAnyIterable, equals, get, getLoadFactor, getTableSize, isEmpty, locateKey, notEmpty, removeAll, removeAll, removeAll, resize, retainAll, setLoadFactor, shrink, size, toArray, toArray

Methods inherited from class java.lang.Object

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

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

rearrange, shuffle, size

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

Methods inherited from interface java.lang.Iterable

forEach

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

getOrderType, random, random, reverse, selectRanked, selectRankedIndex, shuffle, swap

Methods inherited from interface java.util.Set

spliterator

Constructor Details

IdentityOrderedSet

public IdentityOrderedSet(OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(int initialCapacity,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(int initialCapacity,
 float loadFactor,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(Iterator<? extends T> coll,
 OrderType type)

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

Parameters:

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

IdentityOrderedSet

public IdentityOrderedSet(ObjectOrderedSet<? extends T> set,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(Collection<? extends T> coll,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(T[] array,
 int offset,
 int length,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(T[] array,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet(Ordered<T> other,
 int offset,
 int count,
 OrderType type)

IdentityOrderedSet

public IdentityOrderedSet()

IdentityOrderedSet

public IdentityOrderedSet(int initialCapacity)

IdentityOrderedSet

public IdentityOrderedSet(int initialCapacity,
 float loadFactor)

IdentityOrderedSet

public IdentityOrderedSet(Iterator<? extends T> 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

IdentityOrderedSet

public IdentityOrderedSet(ObjectOrderedSet<? extends T> set)

IdentityOrderedSet

public IdentityOrderedSet(Collection<? extends T> coll)

IdentityOrderedSet

public IdentityOrderedSet(T[] array,
 int offset,
 int length)

IdentityOrderedSet

public IdentityOrderedSet(T[] array)

IdentityOrderedSet

public IdentityOrderedSet(Ordered<T> other,
 int offset,
 int count)

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<T>

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<T>

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<T>

Specified by:

hashCode in interface Set<T>

Overrides:

hashCode in class ObjectOrderedSet<T>

getHashMultiplier

public int getHashMultiplier()

Effectively does nothing here because the hashMultiplier is not used by identity hashing.

Overrides:

getHashMultiplier in class ObjectSet<T>

Returns:

any int; the value isn't used internally, but may be used by subclasses to identify something

setHashMultiplier

public void setHashMultiplier(int hashMultiplier)

Effectively does nothing here because the hashMultiplier is not used by identity hashing. Subclasses can use this to set some kind of identifier or user data, though. Unlike the superclass implementation, this does not alter the given int to make it negative or odd.

Overrides:

setHashMultiplier in class ObjectSet<T>

Parameters:

hashMultiplier - any int; will not be used

with

public static <T> IdentityOrderedSet<T> with()

Constructs an empty set given the type as a generic type argument. 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.

Type Parameters:

T - the type of items; must be given explicitly

Returns:

a new set containing nothing

with

public static <T> IdentityOrderedSet<T> with(T item)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item - one T item

Returns:

a new IdentityOrderedSet that holds the given item

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2,
 T item3)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

item3 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2,
 T item3,
 T item4)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

item3 - a T item

item4 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2,
 T item3,
 T item4,
 T item5)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

item3 - a T item

item4 - a T item

item5 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2,
 T item3,
 T item4,
 T item5,
 T item6)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

item3 - a T item

item4 - a T item

item5 - a T item

item6 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

public static <T> IdentityOrderedSet<T> with(T item0,
 T item1,
 T item2,
 T item3,
 T item4,
 T item5,
 T item6,
 T item7)

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

Type Parameters:

T - the type of item, typically inferred

Parameters:

item0 - a T item

item1 - a T item

item2 - a T item

item3 - a T item

item4 - a T item

item5 - a T item

item6 - a T item

Returns:

a new IdentityOrderedSet that holds the given items

with

@SafeVarargs
public static <T> IdentityOrderedSet<T> with(T... varargs)

Creates a new IdentityOrderedSet that holds only the given items, but can be resized. This overload will only be used when an array is supplied and the type of the items requested is the component type of the array, or if varargs are used and there are 9 or more arguments.

Type Parameters:

T - the type of item, typically inferred

Parameters:

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

Returns:

a new IdentityOrderedSet that holds the given items

parse

public static <T> IdentityOrderedSet<T> parse(String str,
 String delimiter,
 PartialParser<T> parser)

Calls 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

parser - a PartialParser that returns a T item from a section of str

Returns:

a new collection parsed from str

parse

public static <T> IdentityOrderedSet<T> parse(String str,
 String delimiter,
 PartialParser<T> parser,
 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

parser - a PartialParser that returns a T item from a section of str

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

Returns:

a new collection parsed from str

parse

public static <T> IdentityOrderedSet<T> parse(String str,
 String delimiter,
 PartialParser<T> parser,
 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

parser - a PartialParser that returns a T item from a section of 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