E
- the type of elements returned by this iteratorEventIterator
, ListIterator<E>
, PrimitiveIterator<T,T_CONS>
, PrimitiveIterator.OfDouble
, PrimitiveIterator.OfInt
, PrimitiveIterator.OfLong
, XMLEventReader
BeanContextSupport.BCSIterator
, EventReaderDelegate
, Scanner
public interface Iterator<E>
Iterator
takes the place of Enumeration
in the Java Collections Framework. Iterators differ from enumerations in two ways: This interface is a member of the Java Collections Framework.
Enumeration
can be converted into an Iterator
by using the Enumeration.asIterator()
method.Modifier and Type | Method | Description |
---|---|---|
default void |
forEachRemaining |
Performs the given action for each remaining element until all elements have been processed or the action throws an exception. |
boolean |
hasNext() |
Returns true if the iteration has more elements. |
E |
next() |
Returns the next element in the iteration. |
default void |
remove() |
Removes from the underlying collection the last element returned by this iterator (optional operation). |
boolean hasNext()
true
if the iteration has more elements. (In other words, returns true
if next()
would return an element rather than throwing an exception.)true
if the iteration has more elementsE next()
NoSuchElementException
- if the iteration has no more elementsdefault void remove()
next()
. The behavior of an iterator is unspecified if the underlying collection is modified while the iteration is in progress in any way other than by calling this method, unless an overriding class has specified a concurrent modification policy.
The behavior of an iterator is unspecified if this method is called after a call to the forEachRemaining
method.
UnsupportedOperationException
and performs no other action.UnsupportedOperationException
- if the remove
operation is not supported by this iteratorIllegalStateException
- if the next
method has not yet been called, or the remove
method has already been called after the last call to the next
methoddefault void forEachRemaining(Consumer<? super E> action)
The behavior of an iterator is unspecified if the action modifies the collection in any way (even by calling the remove
method or other mutator methods of Iterator
subtypes), unless an overriding class has specified a concurrent modification policy.
Subsequent behavior of an iterator is unspecified if the action throws an exception.
The default implementation behaves as if:
while (hasNext())
action.accept(next());
action
- The action to be performed for each elementNullPointerException
- if the specified action is null
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/Iterator.html