org.kocakosm.pitaya.collection

Class Iterables

java.lang.Object

org.kocakosm.pitaya.collection.Iterables

public final class Iterables
extends Object

Static utility methods that operate on or return Iterables.

Author:

Osman KOCAK

Field Summary

Fields

Modifier and Type	Field and Description
static Iterable	EMPTY_ITERABLE The empty Iterable.

Method Summary

Methods

Modifier and Type	Method and Description
static <T> Iterable<T>	concat(Iterable<? extends Iterable<? extends T>> iterables) Concatenates the given Iterables into a single one.
static <T> Iterable<T>	concat(Iterable<? extends T>... iterables) Concatenates the given Iterables into a single one.
static <T> Iterable<T>	cycle(Iterable<? extends T> iterable) Returns a cyclic Iterable that cycles indefinitely over the given Iterable's elements.
static <T> Iterable<T>	cycle(T... elements) Returns an Iterable that cycles indefinitely over the given elements.
static <T> Iterable<T>	emptyIterable() Returns the empty Iterable for a particular type (type-safe).
static boolean	equal(Iterable<?> i1, Iterable<?> i2) Returns whether the given Iterables contain equal elements in the same order.
static <T> Iterable<T>	limit(Iterable<? extends T> iterable, int limit) Returns an Iterable view of the given Iterable that will only return its first limit items.
static <T> Iterable<T>	skip(Iterable<T> iterable, int n) Returns an Iterable view of the given Iterable that skips its first n elements.
static <T> Bag<T>	toBag(Iterable<? extends T> iterable) Returns a Bag containing all the given Iterable's elements.
static <T> List<T>	toList(Iterable<? extends T> iterable) Returns a List containing all the given Iterable's elements.
static <T> Set<T>	toSet(Iterable<? extends T> iterable) Returns a Set containing all the given Iterable's elements.
static String	toString(Iterable<?> iterable) Returns a String representation of the given Iterable using the "[e1, e2, ..., en]" format.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_ITERABLE

public static final Iterable EMPTY_ITERABLE

The empty Iterable.

Method Detail

emptyIterable

public static <T> Iterable<T> emptyIterable()

Returns the empty Iterable for a particular type (type-safe). Note that unlike this method, the like-named static field does not provide type safety.

Type Parameters:

T - the type of the Iterable's elements.

Returns:

the empty Iterable.

concat

public static <T> Iterable<T> concat(Iterable<? extends T>... iterables)

Concatenates the given Iterables into a single one. Note that the returned Iterable is only a view, that is, any subsequent update on any of the input Iterables will affect the returned view. The input Iterables will not be polled until necessary. The returned view's Iterator supports Iterator.remove() when the corresponding input Iterator supports it.

Type Parameters:

T - the type of the returned Iterables' elements.

Parameters:

iterables - the Iterables to concatenate.

Returns:

the concatenated Iterable.

Throws:

NullPointerException - if iterables is null or if it contains a null reference.

concat

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

Concatenates the given Iterables into a single one. Note that the returned Iterable is only a view, that is, any subsequent update on any of the input Iterables will affect the returned view. The input Iterables will not be polled until necessary. The returned view's Iterator supports Iterator.remove() when the corresponding input Iterator supports it.

Type Parameters:

T - the type of the returned Iterables' elements.

Parameters:

iterables - the Iterables to concatenate.

Returns:

the concatenated Iterable.

Throws:

NullPointerException - if iterables is null or if it contains a null reference.

cycle

public static <T> Iterable<T> cycle(Iterable<? extends T> iterable)

Returns a cyclic Iterable that cycles indefinitely over the given Iterable's elements. The returned Iterable's Iterator supports Iterator#remove().

Type Parameters:

T - the type of the returned Iterable's elements.

Parameters:

iterable - the Iterable containing the elements to cycle over.

Returns:

the cyclic Iterable.

Throws:

NullPointerException - if iterable is null.

cycle

public static <T> Iterable<T> cycle(T... elements)

Returns an Iterable that cycles indefinitely over the given elements. The returned Iterable's Iterator supports Iterator.remove().

Type Parameters:

T - the type of the returned Iterable's elements.

Parameters:

elements - the elements to cycle over.

Returns:

the cyclic Iterable.

Throws:

NullPointerException - if iterable is null.

equal

public static boolean equal(Iterable<?> i1,
            Iterable<?> i2)

Returns whether the given Iterables contain equal elements in the same order.

Parameters:

i1 - the first Iterable.

i2 - the second Iterable.

Returns:

whether the given Iterables have the same content.

limit

public static <T> Iterable<T> limit(Iterable<? extends T> iterable,
                    int limit)

Returns an Iterable view of the given Iterable that will only return its first limit items. The returned view's Iterators support Iterator.remove() if the original Iterator does.

Type Parameters:

T - the type of the returned Iterable's elements.

Parameters:

iterable - the Iterable to limit.

limit - the number of elements in the returned Iterable.

Returns:

the limited Iterable.

Throws:

NullPointerException - if iterable is null.

IllegalArgumentException - if (limit is negative.

skip

public static <T> Iterable<T> skip(Iterable<T> iterable,
                   int n)

Returns an Iterable view of the given Iterable that skips its first n elements. The returned Iterable's Iterator supports Iterator.remove() if the original Iterator does.

Type Parameters:

T - the type of the Iterable's elements.

Parameters:

iterable - the input Iterable.

n - the number of items to skip.

Returns:

the skipping Iterable.

Throws:

NullPointerException - if iterable is null.

IllegalArgumentException - if (n is negative.

toList

public static <T> List<T> toList(Iterable<? extends T> iterable)

Returns a List containing all the given Iterable's elements.

Type Parameters:

T - the type of the returned List's elements.

Parameters:

iterable - the source Iterable.

Returns:

the List created from the given Iterable.

Throws:

NullPointerException - if iterable is null.

toSet

public static <T> Set<T> toSet(Iterable<? extends T> iterable)

Returns a Set containing all the given Iterable's elements. The returned Set has the same iteration order as the source Iterable.

Type Parameters:

T - the type of the returned Set's elements.

Parameters:

iterable - the source Iterable.

Returns:

the Set created from the given Iterable.

Throws:

NullPointerException - if iterable is null.

toBag

public static <T> Bag<T> toBag(Iterable<? extends T> iterable)

Returns a Bag containing all the given Iterable's elements. The returned Bag has the same iteration order as the source Iterable.

Type Parameters:

T - the type of the returned Bag's elements.

Parameters:

iterable - the source Iterable.

Returns:

the Bag created from the given Iterable.

Throws:

NullPointerException - if iterable is null.

toString

public static String toString(Iterable<?> iterable)

Returns a String representation of the given Iterable using the "[e1, e2, ..., en]" format.

Parameters:

iterable - the Iterable.

Returns:

the String created from the given Iterable.

Throws:

NullPointerException - if iterable is null.