at.molindo.utils.collections

Class IteratorUtils

java.lang.Object

at.molindo.utils.collections.IteratorUtils

public class IteratorUtils
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
static Iterable<?>	EMPTY_ITERABLE
static Iterator<?>	EMPTY_ITERATOR

Method Summary

Methods

Modifier and Type	Method and Description
static <T,C extends Collection<T>> C	addAll(C collection, Iterator<T> iter) adds all elements from iter to collection
static <T> Iterable<T>	cast(Class<T> cls, Iterable<?> iterable) a type safe cast for Iterable
static <T> Iterable<T>	cast(Class<T> cls, Object[] list) type safe cast from any array to an Iterable
static <T> Iterator<T>	chain(Iterable<Iterator<? extends T>> iterable)
static <T> Iterator<T>	chain(Iterator<? extends T>... iterators)
static <T> Iterator<T>	chain(Iterator<Iterator<? extends T>> iter)
static <T> Iterator<T>	empty() type save access to EMPTY_ITERATOR
static <T> Iterable<T>	emptyIterable() type save access to EMPTY_ITERABLE
static boolean	equals(Iterable<?> iterable1, Iterable<?> iterable2)
static boolean	equals(Iterator<?> iter1, Iterator<?> iter2)
static <T> Iterable<T>	filter(Iterable<T> iterable, Function<T,Boolean> filter)
static <T> Iterator<T>	filter(Iterator<T> iter, Function<T,Boolean> filter)
static <T> T	first(Iterable<T> iter)
static <T> Iterable<T>	iterable(Iterator<T> iter)
static <T> Iterator<T>	iterator(Iterable<T> iterable)
static <T> Iterable<Iterator<T>>	iterators(Iterable<? extends Iterable<T>> iterables) transforms an Iterable of Iterables to an Iterable of Iterators
static <T> Iterator<Iterator<T>>	iterators(Iterator<? extends Iterable<T>> iterables) transforms an Iterator of Iterables to an Iterator of Iterators
static <T> ArrayList<T>	list(Iterable<T> iter)
static <T> ArrayList<T>	list(Iterable<T> iter, int initialCapacity)
static <T> ArrayList<T>	list(Iterator<T> iter)
static <T> ArrayList<T>	list(Iterator<T> iter, int initialCapacity)
static <T> Iterator<T>	max(Iterator<T> iter, int max) don't return more elements than given by max
static <T> T	next(Iterator<T> iter)
static <T> Iterable<T>	notNull(Iterable<T> iter)
static <T> Iterator<T>	notNull(Iterator<T> iter)
static <T> Iterator<T>	object(T o)
static <K,V,M extends Map<K,V>> M	putKeys(M map, Iterator<K> iter, Function<K,V> func) adds all elements from iter to map, generating values using function
static <K,V,M extends Map<K,V>> M	putValues(M map, Iterator<V> iter, Function<V,K> func) adds all elements from iter to map, generating keys using function
static <T> Iterable<T>	readOnly(Iterable<T> iter)
static <T> Iterator<T>	readOnly(Iterator<T> iter)
static <T> Iterator<T>	skip(Iterator<T> iter, int skip) skips a given number of elements in iterator while there are available
static <F,T> Iterable<T>	transform(Iterable<? extends F> iterable, Function<F,T> f)
static <F,T> Iterator<T>	transform(Iterator<? extends F> iter, Function<F,T> f)

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_ITERATOR

public static final Iterator<?> EMPTY_ITERATOR

EMPTY_ITERABLE

public static final Iterable<?> EMPTY_ITERABLE

Method Detail

iterable

public static <T> Iterable<T> iterable(Iterator<T> iter)

Type Parameters:

T -

Parameters:

iter -

Returns:

an Iterable that alway returns the passed Iterator instance

iterator

public static <T> Iterator<T> iterator(Iterable<T> iterable)

Type Parameters:

T -

Parameters:

iterable -

Returns:

Iterable.iterator() or EMPTY_ITERATOR if null

iterators

public static <T> Iterator<Iterator<T>> iterators(Iterator<? extends Iterable<T>> iterables)

transforms an Iterator of Iterables to an Iterator of Iterators

iterators

public static <T> Iterable<Iterator<T>> iterators(Iterable<? extends Iterable<T>> iterables)

transforms an Iterable of Iterables to an Iterable of Iterators

next

public static <T> T next(Iterator<T> iter)

Type Parameters:

T -

Parameters:

iter -

Returns:

the next element if available, null otherwise

first

public static <T> T first(Iterable<T> iter)

Type Parameters:

T -

Parameters:

iter -

Returns:

the first element if available, null otherwise

list

public static <T> ArrayList<T> list(Iterable<T> iter)

Type Parameters:

T -

Parameters:

iter -

Returns:

an ArrayList containing all elements

list

public static <T> ArrayList<T> list(Iterable<T> iter,
                    int initialCapacity)

Type Parameters:

T -

Parameters:

iter -

Returns:

an ArrayList containing all elements

list

public static <T> ArrayList<T> list(Iterator<T> iter)

Type Parameters:

T -

Parameters:

iter -

Returns:

an ArrayList containing all elements

list

public static <T> ArrayList<T> list(Iterator<T> iter,
                    int initialCapacity)

Type Parameters:

T -

Parameters:

iter -

Returns:

an ArrayList containing all elements

addAll

public static <T,C extends Collection<T>> C addAll(C collection,
                                   Iterator<T> iter)

adds all elements from iter to collection

Type Parameters:

T -

C -

Parameters:

collection -

iter -

Returns:

putKeys

public static <K,V,M extends Map<K,V>> M putKeys(M map,
                                 Iterator<K> iter,
                                 Function<K,V> func)

adds all elements from iter to map, generating values using function

Type Parameters:

K -

V -

M -

Parameters:

map -

iter -

func -

Returns:

putValues

public static <K,V,M extends Map<K,V>> M putValues(M map,
                                   Iterator<V> iter,
                                   Function<V,K> func)

adds all elements from iter to map, generating keys using function

Type Parameters:

K -

V -

M -

Parameters:

map -

iter -

func -

Returns:

empty

public static <T> Iterator<T> empty()

type save access to EMPTY_ITERATOR

Type Parameters:

T -

Returns:

emptyIterable

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

type save access to EMPTY_ITERABLE

Type Parameters:

T -

Returns:

notNull

public static <T> Iterator<T> notNull(Iterator<T> iter)

notNull

public static <T> Iterable<T> notNull(Iterable<T> iter)

cast

public static <T> Iterable<T> cast(Class<T> cls,
                   Object[] list)

type safe cast from any array to an Iterable

Type Parameters:

T -

Parameters:

cls -

list -

Returns:

cast

public static <T> Iterable<T> cast(Class<T> cls,
                   Iterable<?> iterable)

a type safe cast for Iterable

Type Parameters:

T -

Parameters:

cls -

iterable -

Returns:

skip

public static <T> Iterator<T> skip(Iterator<T> iter,
                   int skip)

skips a given number of elements in iterator while there are available

Type Parameters:

T -

Parameters:

iter -

skip -

Returns:

max

public static <T> Iterator<T> max(Iterator<T> iter,
                  int max)

don't return more elements than given by max

Type Parameters:

T -

Parameters:

iter -

max -

Returns:

object

public static <T> Iterator<T> object(T o)

filter

public static <T> Iterable<T> filter(Iterable<T> iterable,
                     Function<T,Boolean> filter)

filter

public static <T> Iterator<T> filter(Iterator<T> iter,
                     Function<T,Boolean> filter)

Type Parameters:

T -

Parameters:

iter -

filter - function that returns true if object is allowed

Returns:

transform

public static <F,T> Iterator<T> transform(Iterator<? extends F> iter,
                          Function<F,T> f)

transform

public static <F,T> Iterable<T> transform(Iterable<? extends F> iterable,
                          Function<F,T> f)

equals

public static boolean equals(Iterable<?> iterable1,
             Iterable<?> iterable2)

equals

public static boolean equals(Iterator<?> iter1,
             Iterator<?> iter2)

readOnly

public static <T> Iterable<T> readOnly(@Nonnull
                       Iterable<T> iter)

readOnly

public static <T> Iterator<T> readOnly(@Nonnull
                       Iterator<T> iter)

chain

public static <T> Iterator<T> chain(Iterator<? extends T>... iterators)

chain

public static <T> Iterator<T> chain(Iterable<Iterator<? extends T>> iterable)

chain

public static <T> Iterator<T> chain(Iterator<Iterator<? extends T>> iter)