totalcross.util

Class LinkedHashSet4D<T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<T>

totalcross.util.HashSet4D<T>

totalcross.util.LinkedHashSet4D<T>

All Implemented Interfaces:

java.lang.Cloneable, java.lang.Iterable<T>, java.util.Collection<T>, java.util.Set<T>

public class LinkedHashSet4D<T>
extends HashSet4D<T>
implements java.util.Set<T>, java.lang.Cloneable

This class provides a hashtable-backed implementation of the Set interface, with predictable traversal order.

It uses a hash-bucket approach; that is, hash collisions are handled by linking the new node off of the pre-existing node (or list of nodes). In this manner, techniques such as linear probing (which can cause primary clustering) and rehashing (which does not fit very well with Java's method of precomputing hash codes) are avoided. In addition, this maintains a doubly-linked list which tracks insertion order. Note that the insertion order is not modified if an add simply reinserts an element in the set.

One of the nice features of tracking insertion order is that you can copy a set, and regardless of the implementation of the original, produce the same results when iterating over the copy. This is possible without needing the overhead of TreeSet.

Under ideal circumstances (no collisions), LinkedHashSet offers O(1) performance on most operations. In the worst case (all elements map to the same hash code -- very unlikely), most operations are O(n).

LinkedHashSet accepts the null entry. It is not synchronized, so if you need multi-threaded access, consider using:
Set s = Collections.synchronizedSet(new LinkedHashSet(...));

The iterators are fail-fast, meaning that any structural modification, except for remove() called on the iterator itself, cause the iterator to throw a ConcurrentModificationException rather than exhibit non-deterministic behavior.

Since:

1.4

See Also:

Object.hashCode(), Collection, Set, HashSet, TreeSet, Collections.synchronizedSet(Set)

Constructor Summary

Constructors

Constructor and Description
LinkedHashSet4D() Construct a new, empty HashSet whose backing HashMap has the default capacity (11) and loadFactor (0.75).
LinkedHashSet4D(java.util.Collection<? extends T> c) Construct a new HashSet with the same elements as are in the supplied collection (eliminating any duplicates, of course).
LinkedHashSet4D(int initialCapacity) Construct a new, empty HashSet whose backing HashMap has the supplied capacity and the default load factor (0.75).
LinkedHashSet4D(int initialCapacity, double loadFactor) Construct a new, empty HashSet whose backing HashMap has the supplied capacity and load factor.

Method Summary

Methods inherited from class totalcross.util.HashSet4D

add, clear, clone, contains, isEmpty, iterator, remove, size

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Set

add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, iterator, remove, removeAll, retainAll, size, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

LinkedHashSet4D

public LinkedHashSet4D()

Construct a new, empty HashSet whose backing HashMap has the default capacity (11) and loadFactor (0.75).

LinkedHashSet4D

public LinkedHashSet4D(int initialCapacity)

Construct a new, empty HashSet whose backing HashMap has the supplied capacity and the default load factor (0.75).

Parameters:

initialCapacity - the initial capacity of the backing HashMap

Throws:

java.lang.IllegalArgumentException - if the capacity is negative

LinkedHashSet4D

public LinkedHashSet4D(int initialCapacity,
                       double loadFactor)

Construct a new, empty HashSet whose backing HashMap has the supplied capacity and load factor.

Parameters:

initialCapacity - the initial capacity of the backing HashMap

loadFactor - the load factor of the backing HashMap

Throws:

java.lang.IllegalArgumentException - if either argument is negative, or if loadFactor is POSITIVE_INFINITY or NaN

LinkedHashSet4D

public LinkedHashSet4D(java.util.Collection<? extends T> c)

Construct a new HashSet with the same elements as are in the supplied collection (eliminating any duplicates, of course). The backing storage has twice the size of the collection, or the default size of 11, whichever is greater; and the default load factor (0.75).

Parameters:

c - a collection of initial set elements

Throws:

java.lang.NullPointerException - if c is null