Package it.unimi.dsi.fastutil.objects

Class ObjectIterators

java.lang.Object

it.unimi.dsi.fastutil.objects.ObjectIterators

public final class ObjectIterators
extends java.lang.Object

A class providing static methods and objects that do useful things with type-specific iterators.

See Also:

Iterator

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ObjectIterators.EmptyIterator<K>	A class returning no elements and a type-specific iterator interface.
static class	ObjectIterators.UnmodifiableBidirectionalIterator<K>	An unmodifiable wrapper class for bidirectional iterators.
static class	ObjectIterators.UnmodifiableIterator<K>	An unmodifiable wrapper class for iterators.
static class	ObjectIterators.UnmodifiableListIterator<K>	An unmodifiable wrapper class for list iterators.

Field Summary

Fields

Modifier and Type	Field	Description
static ObjectIterators.EmptyIterator	EMPTY_ITERATOR	An empty iterator.

Method Summary

Modifier and Type	Method	Description
static <K> boolean	all(ObjectIterator<K> iterator, java.util.function.Predicate<? super K> predicate)
static <K> boolean	any(ObjectIterator<K> iterator, java.util.function.Predicate<? super K> predicate)
static <K> ObjectIterator<K>	asObjectIterator(java.util.Iterator<K> i)	Wraps a standard iterator into a type-specific iterator.
static <K> ObjectListIterator<K>	asObjectIterator(java.util.ListIterator<K> i)	Wraps a standard list iterator into a type-specific list iterator.
static <K> ObjectIterator<K>	concat(ObjectIterator<? extends K>[] a)	Concatenates all iterators contained in an array.
static <K> ObjectIterator<K>	concat(ObjectIterator<? extends K>[] a, int offset, int length)	Concatenates a sequence of iterators contained in an array.
static <K> ObjectIterator<K>	emptyIterator()	Returns an empty iterator.
static <K> int	indexOf(ObjectIterator<K> iterator, java.util.function.Predicate<? super K> predicate)
static <K> ObjectList<K>	pour(java.util.Iterator<K> i)	Pours an iterator, returning a type-specific list.
static <K> ObjectList<K>	pour(java.util.Iterator<K> i, int max)	Pours an iterator, returning a type-specific list, with a limit on the number of elements.
static <K> int	pour(java.util.Iterator<K> i, ObjectCollection<? super K> s)	Pours an iterator into a type-specific collection.
static <K> int	pour(java.util.Iterator<K> i, ObjectCollection<? super K> s, int max)	Pours an iterator into a type-specific collection, with a limit on the number of elements.
static <K> ObjectListIterator<K>	singleton(K element)	Returns an immutable iterator that iterates just over the given element.
static <K> ObjectBidirectionalIterator<K>	unmodifiable(ObjectBidirectionalIterator<K> i)	Returns an unmodifiable bidirectional iterator backed by the specified bidirectional iterator.
static <K> ObjectIterator<K>	unmodifiable(ObjectIterator<K> i)	Returns an unmodifiable iterator backed by the specified iterator.
static <K> ObjectListIterator<K>	unmodifiable(ObjectListIterator<K> i)	Returns an unmodifiable list iterator backed by the specified list iterator.
static <K> K[]	unwrap(java.util.Iterator<? extends K> i)	Unwraps an iterator, returning an array.
static <K> K[]	unwrap(java.util.Iterator<? extends K> i, int max)	Unwraps an iterator, returning an array, with a limit on the number of elements.
static <K> int	unwrap(java.util.Iterator<? extends K> i, K[] array)	Unwraps an iterator into an array.
static <K> int	unwrap(java.util.Iterator<? extends K> i, K[] array, int offset, int max)	Unwraps an iterator into an array starting at a given offset for a given number of elements.
static <K> long	unwrap(java.util.Iterator<K> i, ObjectCollection<? super K> c)	Unwraps an iterator into a type-specific collection.
static <K> int	unwrap(java.util.Iterator<K> i, ObjectCollection<? super K> c, int max)	Unwraps an iterator into a type-specific collection, with a limit on the number of elements.
static <K> ObjectListIterator<K>	wrap(K[] array)	Wraps the given array into a type-specific list iterator.
static <K> ObjectListIterator<K>	wrap(K[] array, int offset, int length)	Wraps the given part of an array into a type-specific list iterator.

Methods inherited from class java.lang.Object

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

Field Detail

EMPTY_ITERATOR

public static final ObjectIterators.EmptyIterator EMPTY_ITERATOR

An empty iterator. It is serializable and cloneable.

The class of this objects represent an abstract empty iterator that can iterate as a type-specific (list) iterator.

Method Detail

emptyIterator

public static <K> ObjectIterator<K> emptyIterator()

Returns an empty iterator. It is serializable and cloneable.

The class of the object returned represent an abstract empty iterator that can iterate as a type-specific (list) iterator.

This method provides a typesafe access to EMPTY_ITERATOR.

Returns:

an empty iterator.

singleton

public static <K> ObjectListIterator<K> singleton(K element)

Returns an immutable iterator that iterates just over the given element.

Parameters:

element - the only element to be returned by a type-specific list iterator.

Returns:

an immutable iterator that iterates just over element.

wrap

public static <K> ObjectListIterator<K> wrap(K[] array,
                                             int offset,
                                             int length)

Wraps the given part of an array into a type-specific list iterator.

The type-specific list iterator returned by this method will iterate length times, returning consecutive elements of the given array starting from the one with index offset.

Parameters:

array - an array to wrap into a type-specific list iterator.

offset - the first element of the array to be returned.

length - the number of elements to return.

Returns:

an iterator that will return length elements of array starting at position offset.

wrap

public static <K> ObjectListIterator<K> wrap(K[] array)

Wraps the given array into a type-specific list iterator.

The type-specific list iterator returned by this method will return all elements of the given array.

Parameters:

array - an array to wrap into a type-specific list iterator.

Returns:

an iterator that will the elements of array.

unwrap

public static <K> int unwrap(java.util.Iterator<? extends K> i,
                             K[] array,
                             int offset,
                             int max)

Unwraps an iterator into an array starting at a given offset for a given number of elements.

This method iterates over the given type-specific iterator and stores the elements returned, up to a maximum of length, in the given array starting at offset. The number of actually unwrapped elements is returned (it may be less than max if the iterator emits less than max elements).

Parameters:

i - a type-specific iterator.

array - an array to contain the output of the iterator.

offset - the first element of the array to be returned.

max - the maximum number of elements to unwrap.

Returns:

the number of elements unwrapped.

unwrap

public static <K> int unwrap(java.util.Iterator<? extends K> i,
                             K[] array)

Unwraps an iterator into an array.

This method iterates over the given type-specific iterator and stores the elements returned in the given array. The iteration will stop when the iterator has no more elements or when the end of the array has been reached.

Parameters:

i - a type-specific iterator.

array - an array to contain the output of the iterator.

Returns:

the number of elements unwrapped.

unwrap

public static <K> K[] unwrap(java.util.Iterator<? extends K> i,
                             int max)

Unwraps an iterator, returning an array, with a limit on the number of elements.

This method iterates over the given type-specific iterator and returns an array containing the elements returned by the iterator. At most max elements will be returned.

Parameters:

i - a type-specific iterator.

max - the maximum number of elements to be unwrapped.

Returns:

an array containing the elements returned by the iterator (at most max).

unwrap

public static <K> K[] unwrap(java.util.Iterator<? extends K> i)

Unwraps an iterator, returning an array.

This method iterates over the given type-specific iterator and returns an array containing the elements returned by the iterator.

Parameters:

i - a type-specific iterator.

Returns:

an array containing the elements returned by the iterator.

unwrap

public static <K> int unwrap(java.util.Iterator<K> i,
                             ObjectCollection<? super K> c,
                             int max)

Unwraps an iterator into a type-specific collection, with a limit on the number of elements.

This method iterates over the given type-specific iterator and stores the elements returned, up to a maximum of max, in the given type-specific collection. The number of actually unwrapped elements is returned (it may be less than max if the iterator emits less than max elements).

Parameters:

i - a type-specific iterator.

c - a type-specific collection array to contain the output of the iterator.

max - the maximum number of elements to unwrap.

Returns:

the number of elements unwrapped. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

unwrap

public static <K> long unwrap(java.util.Iterator<K> i,
                              ObjectCollection<? super K> c)

Unwraps an iterator into a type-specific collection.

This method iterates over the given type-specific iterator and stores the elements returned in the given type-specific collection. The returned count on the number unwrapped elements is a long, so that it will work also with very large collections.

Parameters:

i - a type-specific iterator.

c - a type-specific collection to contain the output of the iterator.

Returns:

the number of elements unwrapped. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

pour

public static <K> int pour(java.util.Iterator<K> i,
                           ObjectCollection<? super K> s,
                           int max)

Pours an iterator into a type-specific collection, with a limit on the number of elements.

This method iterates over the given type-specific iterator and adds the returned elements to the given collection (up to max).

Parameters:

i - a type-specific iterator.

s - a type-specific collection.

max - the maximum number of elements to be poured.

Returns:

the number of elements poured. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

pour

public static <K> int pour(java.util.Iterator<K> i,
                           ObjectCollection<? super K> s)

Pours an iterator into a type-specific collection.

This method iterates over the given type-specific iterator and adds the returned elements to the given collection.

Parameters:

i - a type-specific iterator.

s - a type-specific collection.

Returns:

the number of elements poured. Note that this is the number of elements returned by the iterator, which is not necessarily the number of elements that have been added to the collection (because of duplicates).

pour

public static <K> ObjectList<K> pour(java.util.Iterator<K> i,
                                     int max)

Pours an iterator, returning a type-specific list, with a limit on the number of elements.

This method iterates over the given type-specific iterator and returns a type-specific list containing the returned elements (up to max). Iteration on the returned list is guaranteed to produce the elements in the same order in which they appeared in the iterator.

Parameters:

i - a type-specific iterator.

max - the maximum number of elements to be poured.

Returns:

a type-specific list containing the returned elements, up to max.

pour

public static <K> ObjectList<K> pour(java.util.Iterator<K> i)

Pours an iterator, returning a type-specific list.

This method iterates over the given type-specific iterator and returns a list containing the returned elements. Iteration on the returned list is guaranteed to produce the elements in the same order in which they appeared in the iterator.

Parameters:

i - a type-specific iterator.

Returns:

a type-specific list containing the returned elements.

asObjectIterator

public static <K> ObjectIterator<K> asObjectIterator(java.util.Iterator<K> i)

Wraps a standard iterator into a type-specific iterator.

This method wraps a standard iterator into a type-specific one which will handle the type conversions for you. Of course, any attempt to wrap an iterator returning the instances of the wrong class will generate a ClassCastException. The returned iterator is backed by i: changes to one of the iterators will affect the other, too.

If i is already type-specific, it will returned and no new object will be generated.

Parameters:

i - an iterator.

Returns:

a type-specific iterator backed by i.

asObjectIterator

public static <K> ObjectListIterator<K> asObjectIterator(java.util.ListIterator<K> i)

Wraps a standard list iterator into a type-specific list iterator.

This method wraps a standard list iterator into a type-specific one which will handle the type conversions for you. Of course, any attempt to wrap an iterator returning the instances of the wrong class will generate a ClassCastException. The returned iterator is backed by i: changes to one of the iterators will affect the other, too.

If i is already type-specific, it will returned and no new object will be generated.

Parameters:

i - a list iterator.

Returns:

a type-specific list iterator backed by i.

any

public static <K> boolean any(ObjectIterator<K> iterator,
                              java.util.function.Predicate<? super K> predicate)

all

public static <K> boolean all(ObjectIterator<K> iterator,
                              java.util.function.Predicate<? super K> predicate)

indexOf

public static <K> int indexOf(ObjectIterator<K> iterator,
                              java.util.function.Predicate<? super K> predicate)

concat

public static <K> ObjectIterator<K> concat(ObjectIterator<? extends K>[] a)

Concatenates all iterators contained in an array.

This method returns an iterator that will enumerate in order the elements returned by all iterators contained in the given array.

Parameters:

a - an array of iterators.

Returns:

an iterator obtained by concatenation.

concat

public static <K> ObjectIterator<K> concat(ObjectIterator<? extends K>[] a,
                                           int offset,
                                           int length)

Concatenates a sequence of iterators contained in an array.

This method returns an iterator that will enumerate in order the elements returned by a[offset], then those returned by a[offset + 1], and so on up to a[offset + length - 1].

Parameters:

a - an array of iterators.

offset - the index of the first iterator to concatenate.

length - the number of iterators to concatenate.

Returns:

an iterator obtained by concatenation of length elements of a starting at offset.

unmodifiable

public static <K> ObjectIterator<K> unmodifiable(ObjectIterator<K> i)

Returns an unmodifiable iterator backed by the specified iterator.

Parameters:

i - the iterator to be wrapped in an unmodifiable iterator.

Returns:

an unmodifiable view of the specified iterator.

unmodifiable

public static <K> ObjectBidirectionalIterator<K> unmodifiable(ObjectBidirectionalIterator<K> i)

Returns an unmodifiable bidirectional iterator backed by the specified bidirectional iterator.

Parameters:

i - the bidirectional iterator to be wrapped in an unmodifiable bidirectional iterator.

Returns:

an unmodifiable view of the specified bidirectional iterator.

unmodifiable

public static <K> ObjectListIterator<K> unmodifiable(ObjectListIterator<K> i)

Returns an unmodifiable list iterator backed by the specified list iterator.

Parameters:

i - the list iterator to be wrapped in an unmodifiable list iterator.

Returns:

an unmodifiable view of the specified list iterator.