org.apache.commons.collections
public class IteratorUtils extends java.lang.Object
Iterator
instances. The implementations are provided in the
org.apache.commons.collections.iterators
subpackage.Modifier and Type | Method and Description |
---|---|
static java.util.Enumeration |
asEnumeration(java.util.Iterator iterator)
Gets an enumeration that wraps an iterator.
|
static java.util.Iterator |
asIterator(java.util.Enumeration enumeration)
Gets an iterator that provides an iterator view of the given enumeration.
|
static java.util.Iterator |
asIterator(java.util.Enumeration enumeration,
java.util.Collection removeCollection)
Gets an iterator that provides an iterator view of the given enumeration
that will remove elements from the specified collection.
|
static java.util.Iterator |
chainedIterator(java.util.Collection iterators)
Gets an iterator that iterates through a collections of
Iterator s
one after another. |
static java.util.Iterator |
chainedIterator(java.util.Iterator[] iterators)
Gets an iterator that iterates through an array of
Iterator s
one after another. |
static java.util.Iterator |
chainedIterator(java.util.Iterator iterator1,
java.util.Iterator iterator2)
Gets an iterator that iterates through two
Iterator s
one after another. |
static java.util.Iterator |
collatedIterator(java.util.Comparator comparator,
java.util.Collection iterators)
Gets an iterator that provides an ordered iteration over the elements
contained in a collection of
Iterator s. |
static java.util.Iterator |
collatedIterator(java.util.Comparator comparator,
java.util.Iterator[] iterators)
Gets an iterator that provides an ordered iteration over the elements
contained in an array of
Iterator s. |
static java.util.Iterator |
collatedIterator(java.util.Comparator comparator,
java.util.Iterator iterator1,
java.util.Iterator iterator2)
Gets an iterator that provides an ordered iteration over the elements
contained in a collection of ordered
Iterator s. |
static java.util.Iterator |
filteredIterator(java.util.Iterator iterator,
Predicate predicate)
Gets an iterator that filters another iterator.
|
static java.util.ListIterator |
filteredListIterator(java.util.ListIterator listIterator,
Predicate predicate)
Gets a list iterator that filters another list iterator.
|
static java.util.Iterator |
getIterator(java.lang.Object obj)
Gets a suitable Iterator for the given object.
|
static java.util.ListIterator |
singletonListIterator(java.lang.Object object)
Gets a singleton list iterator.
|
static java.lang.Object[] |
toArray(java.util.Iterator iterator)
Gets an array based on an iterator.
|
static java.lang.Object[] |
toArray(java.util.Iterator iterator,
java.lang.Class arrayClass)
Gets an array based on an iterator.
|
static java.util.List |
toList(java.util.Iterator iterator)
Gets a list based on an iterator.
|
static java.util.List |
toList(java.util.Iterator iterator,
int estimatedSize)
Gets a list based on an iterator.
|
static java.util.ListIterator |
toListIterator(java.util.Iterator iterator)
Gets a list iterator based on a simple iterator.
|
static java.util.Iterator |
transformedIterator(java.util.Iterator iterator,
Transformer transform)
Gets an iterator that transforms the elements of another iterator.
|
public static java.util.Enumeration asEnumeration(java.util.Iterator iterator)
iterator
- the iterator to use, not nulljava.lang.NullPointerException
- if iterator is nullpublic static java.util.Iterator asIterator(java.util.Enumeration enumeration)
enumeration
- the enumeration to usepublic static java.util.Iterator asIterator(java.util.Enumeration enumeration, java.util.Collection removeCollection)
enumeration
- the enumeration to usecollection
- the collection to remove elements formpublic static java.util.Iterator chainedIterator(java.util.Collection iterators)
Iterator
s
one after another.iterators
- the iterators to use, not null or empty or contain nullsjava.lang.NullPointerException
- if iterators collection is null or contains a nulljava.lang.ClassCastException
- if the iterators collection contains the wrong object typepublic static java.util.Iterator chainedIterator(java.util.Iterator[] iterators)
Iterator
s
one after another.iterators
- the iterators to use, not null or empty or contain nullsjava.lang.NullPointerException
- if iterators array is null or contains a nullpublic static java.util.Iterator chainedIterator(java.util.Iterator iterator1, java.util.Iterator iterator2)
Iterator
s
one after another.iterator1
- the first iterators to use, not nulliterator2
- the first iterators to use, not nulljava.lang.NullPointerException
- if either iterator is nullpublic static java.util.Iterator collatedIterator(java.util.Comparator comparator, java.util.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 nullsjava.lang.NullPointerException
- if iterators collection is null or contains a nulljava.lang.ClassCastException
- if the iterators collection contains the wrong object typepublic static java.util.Iterator collatedIterator(java.util.Comparator comparator, java.util.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 nullsjava.lang.NullPointerException
- if iterators array is null or contains a nullpublic static java.util.Iterator collatedIterator(java.util.Comparator comparator, java.util.Iterator iterator1, java.util.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 nulljava.lang.NullPointerException
- if either iterator is nullpublic static java.util.Iterator filteredIterator(java.util.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 nulljava.lang.NullPointerException
- if either parameter is nullpublic static java.util.ListIterator filteredListIterator(java.util.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 nulljava.lang.NullPointerException
- if either parameter is nullpublic static java.util.Iterator getIterator(java.lang.Object obj)
This method can handles objects as follows
obj
- the object to convert to an iteratorpublic static java.util.ListIterator singletonListIterator(java.lang.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 java.lang.Object[] toArray(java.util.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 nulljava.lang.NullPointerException
- if iterator parameter is nullpublic static java.lang.Object[] toArray(java.util.Iterator iterator, java.lang.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 createjava.lang.NullPointerException
- if iterator parameter is nulljava.lang.NullPointerException
- if arrayClass is nulljava.lang.ClassCastException
- if the arrayClass is invalidpublic static java.util.List toList(java.util.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 nulljava.lang.NullPointerException
- if iterator parameter is nullpublic static java.util.List toList(java.util.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 ArrayListjava.lang.NullPointerException
- if iterator parameter is nulljava.lang.IllegalArgumentException
- if the size is less than 1public static java.util.ListIterator toListIterator(java.util.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 nulljava.lang.NullPointerException
- if iterator parameter is nullpublic static java.util.Iterator transformedIterator(java.util.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 nulljava.lang.NullPointerException
- if either parameter is nullCopyright © 2001-2004 Apache Software Foundation. Documenation generated February 26 2016.