Package hudson.util

Class Iterators

java.lang.Object

hudson.util.Iterators

public class Iterators
extends Object

Varios Iterator implementations.

Author:

Kohsuke Kawaguchi

See Also:

• AdaptedIterator

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	Iterators.CountingPredicate<T>
static final class	Iterators.DuplicateFilterIterator<T>	Remove duplicates from another iterator.
static class	Iterators.FilterIterator<T>	Creates a filtered view of another iterator.
static class	Iterators.FlattenIterator<U,T>	Produces {A,B,C,D,E,F} from {{A,B},{C},{},{D,E,F}}.

Constructor Summary

Constructors

Constructor	Description
Iterators()

Method Summary

Modifier and Type	Method	Description
static <T> Iterable<T>	cast(Iterable<? extends T> itr)	Casts Iterable by taking advantage of its covariant-ness.
static <T> Iterator<T>	cast(Iterator<? extends T> itr)	Casts Iterator by taking advantage of its covariant-ness.
static <T> Iterator<T>	empty()	Returns the empty iterator.
static <T> Iterator<T>	limit(Iterator<? extends T> base, Iterators.CountingPredicate<? super T> filter)	Returns the elements in the base iterator until it hits any element that doesn't satisfy the filter.
static <T, U> Iterator<U>	map(Iterator<T> itr, Function<T,U> mapper)	Wraps another iterator and map iterable objects.
static <T> Iterator<T>	readOnly(Iterator<T> itr)	Creates a read-only mutator that disallows Iterator.remove().
static <T> Iterable<T>	removeDups(Iterable<T> base)	Filters another iterator by eliminating duplicates.
static <T> Iterator<T>	removeDups(Iterator<T> iterator)	Filters another iterator by eliminating duplicates.
static <T> Iterator<T>	removeNull(Iterator<T> itr)	Wraps another iterator and throws away nulls.
static <T> Iterable<T>	reverse(List<T> lst)	Returns the Iterable that lists items in the reverse order.
static List<Integer>	reverseSequence(int start, int end)
static List<Integer>	reverseSequence(int start, int end, int step)	The short cut for reverse(sequence(start,end,step)).
static List<Integer>	sequence(int start, int end)
static List<Integer>	sequence(int start, int end, int step)	Returns a list that represents [start,end).
static <T> Iterable<T>	sequence(Iterable<? extends T>... iterables)	Returns an Iterable that iterates over all the given Iterables.
static <T> Iterator<T>	sequence(Iterator<? extends T>... iterators)
static void	skip(Iterator<?> iterator, int count)	Calls next() on iterator, either count times or until hasNext() returns false, whichever comes first.
static <U, T extends U> Iterator<T>	subType(Iterator<U> itr, Class<T> type)	Returns an Iterator that only returns items of the given subtype.
static <T> Iterable<T>	wrap(Iterable<T> base)	Returns an Iterable that lists items in the normal order but which hides the base iterator implementation details.

Methods inherited from class java.lang.Object

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

Constructor Details

Iterators

public Iterators()

Method Details

empty

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

Returns the empty iterator.

reverse

public static <T> Iterable<T> reverse(List<T> lst)

Returns the Iterable that lists items in the reverse order.

Since:

1.150

wrap

public static <T> Iterable<T> wrap(Iterable<T> base)

Returns an Iterable that lists items in the normal order but which hides the base iterator implementation details.

Since:

1.492

sequence

public static List<Integer> sequence(int start,
 int end,
 int step)

Returns a list that represents [start,end). For example sequence(1,5,1)={1,2,3,4}, and sequence(7,1,-2)={7.5,3}

Since:

1.150

sequence

public static List<Integer> sequence(int start,
 int end)

reverseSequence

public static List<Integer> reverseSequence(int start,
 int end,
 int step)

The short cut for reverse(sequence(start,end,step)).

Since:

1.150

reverseSequence

public static List<Integer> reverseSequence(int start,
 int end)

cast

public static <T> Iterator<T> cast(Iterator<? extends T> itr)

Casts Iterator by taking advantage of its covariant-ness.

cast

public static <T> Iterable<T> cast(Iterable<? extends T> itr)

Casts Iterable by taking advantage of its covariant-ness.

subType

public static <U,
T extends U> Iterator<T> subType(Iterator<U> itr,
 Class<T> type)

Returns an Iterator that only returns items of the given subtype.

readOnly

public static <T> Iterator<T> readOnly(Iterator<T> itr)

Creates a read-only mutator that disallows Iterator.remove().

removeNull

public static <T> Iterator<T> removeNull(Iterator<T> itr)

Wraps another iterator and throws away nulls.

map

public static <T,
U> Iterator<U> map(Iterator<T> itr,
 Function<T,U> mapper)

Wraps another iterator and map iterable objects.

sequence

@SafeVarargs
public static <T> Iterable<T> sequence(Iterable<? extends T>... iterables)

Returns an Iterable that iterates over all the given Iterables.

That is, this creates {A,B,C,D} from {A,B},{C,D}.

removeDups

public static <T> Iterator<T> removeDups(Iterator<T> iterator)

Filters another iterator by eliminating duplicates.

removeDups

public static <T> Iterable<T> removeDups(Iterable<T> base)

Filters another iterator by eliminating duplicates.

sequence

@SafeVarargs
public static <T> Iterator<T> sequence(Iterator<? extends T>... iterators)

limit

public static <T> Iterator<T> limit(Iterator<? extends T> base,
 Iterators.CountingPredicate<? super T> filter)

Returns the elements in the base iterator until it hits any element that doesn't satisfy the filter. Then the rest of the elements in the base iterator gets ignored.

Since:

1.485

skip

@Restricted(org.kohsuke.accmod.restrictions.NoExternalUse.class)
public static void skip(@NonNull
 Iterator<?> iterator,
 int count)

Calls next() on iterator, either count times or until hasNext() returns false, whichever comes first.

Parameters:

iterator - some iterator

count - a nonnegative count