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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object | +--org.apache.commons.collections.IteratorUtils
Provides static utility methods and decorators for Iterator
instances. The implementations are provided in the
org.apache.commons.collections.iterators
subpackage.
Field Summary | |
static Iterator |
EMPTY_ITERATOR
An iterator over no elements |
static ListIterator |
EMPTY_LIST_ITERATOR
A list iterator over no elements |
Method Summary | |
static Iterator |
arrayIterator(Object[] array)
Gets an iterator over an array. |
static Iterator |
arrayIterator(Object[] array,
int start)
Gets an iterator over the end part of an array. |
static Iterator |
arrayIterator(Object[] array,
int start,
int end)
Gets an iterator over part of an array. |
static Enumeration |
asEnumeration(Iterator iterator)
Gets an enumeration that wraps an iterator. |
static Iterator |
asIterator(Enumeration enumeration)
Gets an iterator that provides an iterator view of the given enumeration. |
static Iterator |
asIterator(Enumeration enumeration,
Collection removeCollection)
Gets an iterator that provides an iterator view of the given enumeration that will remove elements from the specified collection. |
static Iterator |
chainedIterator(Collection iterators)
Gets an iterator that iterates through a collections of Iterator s
one after another. |
static Iterator |
chainedIterator(Iterator[] iterators)
Gets an iterator that iterates through an array of Iterator s
one after another. |
static Iterator |
chainedIterator(Iterator iterator1,
Iterator iterator2)
Gets an iterator that iterates through two Iterator s
one after another. |
static Iterator |
collatedIterator(Comparator comparator,
Collection iterators)
Gets an iterator that provides an ordered iteration over the elements contained in a collection of Iterator s. |
static Iterator |
collatedIterator(Comparator comparator,
Iterator[] iterators)
Gets an iterator that provides an ordered iteration over the elements contained in an array of Iterator s. |
static Iterator |
collatedIterator(Comparator comparator,
Iterator iterator1,
Iterator iterator2)
Gets an iterator that provides an ordered iteration over the elements contained in a collection of ordered Iterator s. |
static Iterator |
emptyIterator()
Gets an empty iterator. |
static ListIterator |
emptyListIterator()
Gets an empty list iterator. |
static Iterator |
filteredIterator(Iterator iterator,
Predicate predicate)
Gets an iterator that filters another iterator. |
static ListIterator |
filteredListIterator(ListIterator listIterator,
Predicate predicate)
Gets a list iterator that filters another list iterator. |
static Iterator |
getIterator(Object obj)
Gets a suitable Iterator for the given object. |
static Iterator |
singletonIterator(Object object)
Gets a singleton iterator. |
static ListIterator |
singletonListIterator(Object object)
Gets a singleton list iterator. |
static Object[] |
toArray(Iterator iterator)
Gets an array based on an iterator. |
static Object[] |
toArray(Iterator iterator,
Class arrayClass)
Gets an array based on an iterator. |
static List |
toList(Iterator iterator)
Gets a list based on an iterator. |
static List |
toList(Iterator iterator,
int estimatedSize)
Gets a list based on an iterator. |
static ListIterator |
toListIterator(Iterator iterator)
Gets a list iterator based on a simple iterator. |
static Iterator |
transformedIterator(Iterator iterator,
Transformer transform)
Gets an iterator that transforms the elements of another iterator. |
Methods inherited from class java.lang.Object |
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait |
Field Detail |
public static final Iterator EMPTY_ITERATOR
public static final ListIterator EMPTY_LIST_ITERATOR
Method Detail |
public static Iterator emptyIterator()
This iterator is a valid iterator object that will iterate over nothing.
public static ListIterator emptyListIterator()
This iterator is a valid list iterator object that will iterate over nothing.
public static Iterator singletonIterator(Object object)
This iterator is a valid iterator object that will iterate over the specified object.
object
- the single object over which to iteratepublic static ListIterator singletonListIterator(Object object)
This iterator is a valid list iterator object that will iterate over the specified object.
object
- the single object over which to iteratepublic static Iterator arrayIterator(Object[] array)
array
- the array over which to iteratepublic static Iterator arrayIterator(Object[] array, int start)
array
- the array over which to iteratestart
- the index to start iterating atpublic static Iterator arrayIterator(Object[] array, int start, int end)
array
- the array over which to iteratestart
- the index to start iterating atend
- the index to finish iterating atpublic static Iterator chainedIterator(Iterator iterator1, Iterator iterator2)
Iterator
s
one after another.iterator1
- the first iterators to use, not nulliterator2
- the first iterators to use, not nullpublic static Iterator chainedIterator(Iterator[] iterators)
Iterator
s
one after another.iterators
- the iterators to use, not null or empty or contain nullspublic static Iterator chainedIterator(Collection iterators)
Iterator
s
one after another.iterators
- the iterators to use, not null or empty or contain nullspublic static Iterator collatedIterator(Comparator comparator, Iterator iterator1, Iterator iterator2)
Iterator
s.
Given two ordered Iterator
s A
and B
,
the Iterator.next()
method will return the lesser of
A.next()
and B.next()
.
The comparator is optional. If null is specified then natural order is used.
comparator
- the comparator to use, may be null for natural orderiterator1
- the first iterators to use, not nulliterator2
- the first iterators to use, not nullpublic static Iterator collatedIterator(Comparator comparator, Iterator[] iterators)
Iterator
s.
Given two ordered Iterator
s A
and B
,
the Iterator.next()
method will return the lesser of
A.next()
and B.next()
and so on.
The comparator is optional. If null is specified then natural order is used.
comparator
- the comparator to use, may be null for natural orderiterators
- the iterators to use, not null or empty or contain nullspublic static Iterator collatedIterator(Comparator comparator, Collection iterators)
Iterator
s.
Given two ordered Iterator
s A
and B
,
the Iterator.next()
method will return the lesser of
A.next()
and B.next()
and so on.
The comparator is optional. If null is specified then natural order is used.
comparator
- the comparator to use, may be null for natural orderiterators
- the iterators to use, not null or empty or contain nullspublic static Iterator transformedIterator(Iterator iterator, Transformer transform)
The transformation occurs during the next() method and the underlying iterator is unaffected by the transformation.
iterator
- the iterator to use, not nulltransform
- the transform to use, not nullpublic static Iterator filteredIterator(Iterator iterator, Predicate predicate)
The returned iterator will only return objects that match the specified filtering predicate.
iterator
- the iterator to use, not nullpredicate
- the predicate to use as a filter, not nullpublic static ListIterator filteredListIterator(ListIterator listIterator, Predicate predicate)
The returned iterator will only return objects that match the specified filtering predicate.
listIterator
- the list iterator to use, not nullpredicate
- the predicate to use as a filter, not nullpublic static Iterator asIterator(Enumeration enumeration)
enumeration
- the enumeration to usepublic static Iterator asIterator(Enumeration enumeration, Collection removeCollection)
enumeration
- the enumeration to usecollection
- the collection to remove elements formpublic static Enumeration asEnumeration(Iterator iterator)
iterator
- the iterator to use, not nullpublic static ListIterator toListIterator(Iterator iterator)
As the wrapped Iterator is traversed, a LinkedList of its values is cached, permitting all required operations of ListIterator.
iterator
- the iterator to use, not nullpublic static Object[] toArray(Iterator iterator)
As the wrapped Iterator is traversed, an ArrayList of its values is created. At the end, this is converted to an array.
iterator
- the iterator to use, not nullpublic static Object[] toArray(Iterator iterator, Class arrayClass)
As the wrapped Iterator is traversed, an ArrayList of its values is created. At the end, this is converted to an array.
iterator
- the iterator to use, not nullarrayClass
- the class of array to createpublic static List toList(Iterator iterator)
As the wrapped Iterator is traversed, an ArrayList of its values is created. At the end, the list is returned.
iterator
- the iterator to use, not nullpublic static List toList(Iterator iterator, int estimatedSize)
As the wrapped Iterator is traversed, an ArrayList of its values is created. At the end, the list is returned.
iterator
- the iterator to use, not nullestimatedSize
- the initial size of the ArrayListpublic static Iterator getIterator(Object obj)
This method can handles objects as follows
obj
- the object to convert to an iterator
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