Package org.organicdesign.fp.collections

Class PersistentTreeSet<E>

java.lang.Object

org.organicdesign.fp.collections.AbstractUnmodIterable<T>

org.organicdesign.fp.collections.AbstractUnmodSet<E>

org.organicdesign.fp.collections.PersistentTreeSet<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>, java.util.SortedSet<E>, BaseSet<E>, ImSortedSet<E>, Sized, UnmodCollection<E>, UnmodIterable<E>, UnmodSet<E>, UnmodSortedCollection<E>, UnmodSortedIterable<E>, UnmodSortedSet<E>, Transformable<E>

public class PersistentTreeSet<E>
extends AbstractUnmodSet<E>
implements ImSortedSet<E>, java.io.Serializable

A wrapper that turns a PersistentTreeMap into a set. This file is a derivative work based on a Clojure collection licensed under the Eclipse Public License 1.0 Copyright Rich Hickey. Errors by Glen Peterson.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static PersistentTreeSet	EMPTY	Be extremely careful with this because it uses the default comparator, which only works for items that implement Comparable (have a "natural ordering").

Method Summary

Modifier and Type	Method	Description
java.util.Comparator<? super E>	comparator()	Returns the comparator used to order the items in this set, or null if it uses Fn2.DEFAULT_COMPARATOR (for compatibility with java.util.SortedSet).
boolean	contains(java.lang.Object o)	Returns true if the set contains the given item in O(log n) time.
static <T extends java.lang.Comparable<T>> PersistentTreeSet<T>	empty()	Be extremely careful with this because it uses the default comparator, which only works for items that implement Comparable (have a "natural ordering").
boolean	equals(java.lang.Object other)	This is designed to be correct, rather than fully compatible with TreeSet.equals().
E	first()	Use head() inherited from Sequence instead of this method which is inherited from SortedSet.
Option<E>	head()	The first item in this iterable.
boolean	isEmpty()	This is a convenience method inherited from Collection that returns true if size() == 0 (if this set contains no elements).
UnmodSortedIterator<E>	iterator()	Iterates over contents in a guaranteed order.
E	last()	Inherited from SortedSet, returns the last item in this set, or throw an exception if this set is empty.
static <T extends java.lang.Comparable<T>> PersistentTreeSet<T>	of(java.lang.Iterable<T> items)	Returns a new PersistentTreeSet of the given comparable items.
static <T> PersistentTreeSet<T>	ofComp(java.util.Comparator<? super T> comp)	Returns a new PersistentTreeSet of the given comparator.
static <T> PersistentTreeSet<T>	ofComp(java.util.Comparator<? super T> comp, java.lang.Iterable<T> elements)	Returns a new PersistentTreeSet of the given comparator and items.
static <T> PersistentTreeSet<T>	ofMap(ImSortedMap<T,?> i)	Returns a new PersistentTreeSet of the keys and comparator in the given map.
PersistentTreeSet<E>	put(E e)	Adds an element.
int	size()	The size of this set.
ImSortedSet<E>	subSet(E fromElement, E toElement)	Return the elements in this set from the start element (inclusive) to the end element (exclusive)
ImSortedSet<E>	tailSet(E fromElement)
PersistentTreeSet<E>	without(E key)	Removes this key from the set

Methods inherited from class org.organicdesign.fp.collections.AbstractUnmodIterable

hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, stream, toArray

Methods inherited from interface org.organicdesign.fp.collections.ImSortedSet

headSet, union

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

add, addAll, clear, containsAll, hashCode, remove, removeAll, retainAll, toArray, toArray

Methods inherited from interface java.util.SortedSet

spliterator

Methods inherited from interface org.organicdesign.fp.xform.Transformable

toImList, toImMap, toImRrbt, toImSet, toImSortedMap, toImSortedSet, toMutableList, toMutableMap, toMutableRrbt, toMutableSet, toMutableSortedMap, toMutableSortedSet

Methods inherited from interface org.organicdesign.fp.collections.UnmodIterable

concat, drop, dropWhile, filter, flatMap, fold, foldUntil, map, precat, take, takeWhile

Methods inherited from interface org.organicdesign.fp.collections.UnmodSet

add, addAll, clear, containsAll, remove, removeAll, removeIf, retainAll, toArray, toArray

Field Detail

EMPTY

public static final PersistentTreeSet EMPTY

Be extremely careful with this because it uses the default comparator, which only works for items that implement Comparable (have a "natural ordering"). An attempt to use it with other items will blow up at runtime. Either a withComparator() method will be added, or this will be removed.

Method Detail

empty

public static <T extends java.lang.Comparable<T>> PersistentTreeSet<T> empty()

Be extremely careful with this because it uses the default comparator, which only works for items that implement Comparable (have a "natural ordering"). An attempt to use it with other items will blow up at runtime. Either a withComparator() method will be added, or this will be removed.

ofComp

public static <T> PersistentTreeSet<T> ofComp(java.util.Comparator<? super T> comp)

Returns a new PersistentTreeSet of the given comparator. Always use this instead of starting with empty() because there is no way to assign a comparator to an existing set.

ofComp

public static <T> PersistentTreeSet<T> ofComp(java.util.Comparator<? super T> comp,
                                              java.lang.Iterable<T> elements)

Returns a new PersistentTreeSet of the given comparator and items.

Parameters:

comp - A comparator that defines the sort order of elements in the new set. This becomes part of the set (it's not for pre-sorting).

elements - items to go into the set. In the case of a duplicate element, later values in the input list overwrite the earlier ones.

Returns:

a new PersistentTreeSet of the specified comparator and the given elements

of

public static <T extends java.lang.Comparable<T>> PersistentTreeSet<T> of(java.lang.Iterable<T> items)

Returns a new PersistentTreeSet of the given comparable items.

ofMap

public static <T> PersistentTreeSet<T> ofMap(ImSortedMap<T,?> i)

Returns a new PersistentTreeSet of the keys and comparator in the given map. Since PersistentTreeSet is just a wrapper for a PersistentTreeMap, this can be a very cheap operation.

comparator

public java.util.Comparator<? super E> comparator()

Returns the comparator used to order the items in this set, or null if it uses Fn2.DEFAULT_COMPARATOR (for compatibility with java.util.SortedSet).

Specified by:

comparator in interface java.util.SortedSet<E>

contains

public boolean contains(java.lang.Object o)

Returns true if the set contains the given item in O(log n) time. This is the defining method of a set.

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.Set<E>

Specified by:

contains in interface UnmodSet<E>

without

public PersistentTreeSet<E> without(E key)

Removes this key from the set

Specified by:

without in interface BaseSet<E>

Specified by:

without in interface ImSortedSet<E>

iterator

public UnmodSortedIterator<E> iterator()

Iterates over contents in a guaranteed order. Iterates over contents with no guarantees about their ordering. An unmodifiable iterator A one-time use, mutable, not-thread-safe way to get each value of the underling collection in turn. I experimented with various thread-safe alternatives, but the JVM is optimized around iterators so this is the lowest common denominator of collection iteration, even though iterators are inherently mutable.

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in interface ImSortedSet<E>

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Set<E>

Specified by:

iterator in interface UnmodCollection<E>

Specified by:

iterator in interface UnmodIterable<E>

Specified by:

iterator in interface UnmodSet<E>

Specified by:

iterator in interface UnmodSortedCollection<E>

Specified by:

iterator in interface UnmodSortedIterable<E>

Specified by:

iterator in interface UnmodSortedSet<E>

equals

public boolean equals(java.lang.Object other)

This is designed to be correct, rather than fully compatible with TreeSet.equals(). TreeSet.equals() does not take ordering into account and this does. You want better equality? Define an Equator. This is for Java@trade; interop.

Specified by:

equals in interface java.util.Collection<E>

Specified by:

equals in interface java.util.Set<E>

Overrides:

equals in class AbstractUnmodSet<E>

first

public E first()

Use head() inherited from Sequence instead of this method which is inherited from SortedSet. This method returns the first element if it exists, or throws a NoSuchElementException if the set is empty. head() returns an Option of the first element where as this method throws an exception if this set is empty. I had to rename the method on Sequence from first() to head() to work around this. Also returning an Option is thread-safe for building a lazy sequence. The alternative, examining the rest() of a sequence to see if it's == Sequence.empty() gets ugly very quickly and makes many transformations eager (especially flatMap).

Specified by:

first in interface java.util.SortedSet<E>

head

public Option<E> head()

The first item in this iterable.

Specified by:

head in interface Transformable<E>

Specified by:

head in interface UnmodIterable<E>

Returns:

an eagerly evaluated result which is a single item.

isEmpty

public boolean isEmpty()

This is a convenience method inherited from Collection that returns true if size() == 0 (if this set contains no elements).

Specified by:

isEmpty in interface java.util.Collection<E>

Specified by:

isEmpty in interface java.util.Set<E>

Specified by:

isEmpty in interface UnmodCollection<E>

Specified by:

isEmpty in interface UnmodSet<E>

last

public E last()

Inherited from SortedSet, returns the last item in this set, or throw an exception if this set is empty. Good luck with that.

Specified by:

last in interface java.util.SortedSet<E>

put

public PersistentTreeSet<E> put(E e)

Adds an element. If the element already exists in this set, the new value overwrites the old one. If the new element is the same as an old element (based on the address of that item in memory, not an equals test), the old set may be returned unchanged.

Specified by:

put in interface BaseSet<E>

Specified by:

put in interface ImSortedSet<E>

Parameters:

e - the element to add to this set

Returns:

a new set with the element added (see note above about adding duplicate elements).

size

public int size()

The size of this set.

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in interface java.util.Set<E>

Specified by:

size in interface Sized

subSet

public ImSortedSet<E> subSet(E fromElement,
                             E toElement)

Return the elements in this set from the start element (inclusive) to the end element (exclusive)

Specified by:

subSet in interface ImSortedSet<E>

Specified by:

subSet in interface java.util.SortedSet<E>

Specified by:

subSet in interface UnmodSortedSet<E>

tailSet

public ImSortedSet<E> tailSet(E fromElement)

Specified by:

tailSet in interface ImSortedSet<E>

Specified by:

tailSet in interface java.util.SortedSet<E>

Specified by:

tailSet in interface UnmodSortedSet<E>