de.unkrig.commons.util.collections

Class IterableUtil

java.lang.Object

de.unkrig.commons.util.collections.IterableUtil

public final class IterableUtil
extends Object

Various Iterable-related utility methods.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	IterableUtil.ElementWithContext<T> A helper interface which extends the "iterator" pattern with the possibility to access not only the "current" element, but also the previous and next element.

Method Summary

Modifier and Type	Method and Description
static <T> Collection<T>	asCollection(Iterable<T> delegate) Wraps the given Iterable in a collection, which, as enforced by the nature of the Iterable, supports only element removal.
static <T> Iterable<T>	concat(Iterable<? extends Iterable<? extends T>> elements)
static <T> Iterable<T>	concat(Iterable<? extends T> element1, Iterable<? extends T> element2)
static <T> Iterable<T>	concat(Iterable<? extends T> element1, Iterable<? extends T> element2, Iterable<? extends T> element3)
static <T> Iterable<T>	concat(Iterable<? extends T> element1, Iterable<? extends T> element2, Iterable<? extends T> element3, Iterable<? extends T> element4)
static <T> Iterable<T>	concat(Iterable<? extends T> element1, T... element2)
static <T> Iterable<T>	concat(T element1, Iterable<? extends T> element2)
static <T> Iterable<T>	concat(T element1, T element2, Iterable<? extends T> element3)
static <T> Iterable<T>	filter(Iterable<? extends T> delegate, Predicate<? super T> qualifies) Returns an Iterable which hides the elements of the delegate which do not qualifiy.
static <T> Iterable<IterableUtil.ElementWithContext<T>>	iterableWithContext(Iterable<? extends T> delegate)
static <T> Iterator<IterableUtil.ElementWithContext<T>>	iteratorWithContext(Iterable<? extends T> iterable)
static <T> Iterable<T>	repeat(T subject, int n)
static <E> Iterable<E>	reverseList(List<? extends E> list)
static <I,O> Iterable<O>	transform(Iterable<? extends I> delegate, Transformer<? super I,? extends O> transform) Returns an iterable which contains the transformed elements of the delegate
static <T> Iterable<T>	unmodifiableIterable(Iterable<? extends T> i)

Methods inherited from class java.lang.Object

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

Method Detail

unmodifiableIterable

public static <T> Iterable<T> unmodifiableIterable(Iterable<? extends T> i)

Returns:

An Iterable which can't be modified through the Iterator.remove() method

repeat

public static <T> Iterable<T> repeat(T subject,
                                     int n)

Returns:

An Iterable producing the given subject n times

reverseList

public static <E> Iterable<E> reverseList(List<? extends E> list)

Returns:

An Iterable that traverses the elements of the given List in reverse order.

concat

public static <T> Iterable<T> concat(T element1,
                                     Iterable<? extends T> element2)

Returns:

An iterator for element1 and the elements of element2

concat

public static <T> Iterable<T> concat(T element1,
                                     T element2,
                                     Iterable<? extends T> element3)

Returns:

An iterator for element1 element2 and the elements of element3

concat

public static <T> Iterable<T> concat(Iterable<? extends T> element1,
                                     T... element2)

Returns:

An iterator for the elements of element1 and element2

concat

public static <T> Iterable<T> concat(Iterable<? extends T> element1,
                                     Iterable<? extends T> element2)

Returns:

An iterator for the elements of element1 and element2

concat

public static <T> Iterable<T> concat(Iterable<? extends T> element1,
                                     Iterable<? extends T> element2,
                                     Iterable<? extends T> element3)

Returns:

An iterator for the elements of element1, element2 and element3

concat

public static <T> Iterable<T> concat(Iterable<? extends T> element1,
                                     Iterable<? extends T> element2,
                                     Iterable<? extends T> element3,
                                     Iterable<? extends T> element4)

Returns:

An iterator for the elements of element1, element2, element3 and element4

concat

public static <T> Iterable<T> concat(Iterable<? extends Iterable<? extends T>> elements)

Returns:

An iterator for the elements of the given elements

filter

public static <T> Iterable<T> filter(Iterable<? extends T> delegate,
                                     Predicate<? super T> qualifies)

Returns an Iterable which hides the elements of the delegate which do not qualifiy.

transform

public static <I,O> Iterable<O> transform(Iterable<? extends I> delegate,
                                          Transformer<? super I,? extends O> transform)

Returns an iterable which contains the transformed elements of the delegate

asCollection

public static <T> Collection<T> asCollection(Iterable<T> delegate)

Wraps the given Iterable in a collection, which, as enforced by the nature of the Iterable, supports only element removal.

iterableWithContext

public static <T> Iterable<IterableUtil.ElementWithContext<T>> iterableWithContext(Iterable<? extends T> delegate)

Returns:

An iterable which wraps the given delegate

iteratorWithContext

public static <T> Iterator<IterableUtil.ElementWithContext<T>> iteratorWithContext(Iterable<? extends T> iterable)

Parameters:

iterable - Must produce non-null values

Returns:

An iterator that produces IterableUtil.ElementWithContexts for the elements of the given iterable