org.key_project.util.collection

Class Immutables

java.lang.Object

org.key_project.util.collection.Immutables

public final class Immutables
extends java.lang.Object

This class is a collection of methods that operate on immutable collections, in particular ImmutableSets and ImmutableLists. This class cannot be instantiated.

Author:

Mattias Ulbrich

Constructor Summary

Constructors

Modifier	Constructor and Description
private	Immutables()

Method Summary

Modifier and Type	Method and Description
static <T> ImmutableList<T>	concatDuplicateFreeLists(ImmutableList<T> l1, ImmutableList<? extends T> l2)
static <T> ImmutableList<T>	createListFrom(java.lang.Iterable<T> iterable)
static <T> ImmutableSet<T>	createSetFrom(java.lang.Iterable<T> iterable)
static <T> boolean	isDuplicateFree(ImmutableList<T> list) Checks whether an immutable list is free of duplicates.
static <T> ImmutableList<T>	removeDuplicates(ImmutableList<T> list) Removes duplicate entries from an immutable list.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Immutables

private Immutables()

Method Detail

isDuplicateFree

public static <T> boolean isDuplicateFree(ImmutableList<T> list)

Checks whether an immutable list is free of duplicates. A list has a duplicate if it during iteration it visits two objects o1 and o2 such that o1==null ? o2 == null : o1.equals(o2) is true. null may appear in the list. The implementation uses a hash set internally and thus runs in O(n).

Parameters:

list - any list, must not be null

Returns:

true iff every

removeDuplicates

public static <T> ImmutableList<T> removeDuplicates(ImmutableList<T> list)

Removes duplicate entries from an immutable list. A list has a duplicate if it during iteration it visits two objects o1 and o2 such that o1==null ? o2 == null : o1.equals(o2) is true. null may appear in the list. If an element occurs duplicated, its first (in order of iteration) occurrence is kept, while later occurrences are removeed. If a list iterates "a", "b", "a" in this order, removeDuplicates returns a list iterating "a", "b". The implementation uses a hash set internally and thus runs in O(n). It reuses as much created datastructure as possible. In particular, if the list is already duplicate-fre, it does not allocate new memory (well, only temporarily) and returns the argument. Sidenote: Would that not make a nice KeY-Verification condition? Eat your own dogfood.

Parameters:

list - any list, must not be null

Returns:

a duplicate-free version of the argument, never null

concatDuplicateFreeLists

public static <T> ImmutableList<T> concatDuplicateFreeLists(ImmutableList<T> l1,
                                                            ImmutableList<? extends T> l2)

createSetFrom

public static <T> ImmutableSet<T> createSetFrom(java.lang.Iterable<T> iterable)

createListFrom

public static <T> ImmutableList<T> createListFrom(java.lang.Iterable<T> iterable)