public interface Iterator<E>
Known subtypesForm.TabIterator, ListIterator
An Iterator is used to sequence over a collection of objects.
Conceptually, an iterator is always positioned between two elements of a
collection. A fresh iterator is always positioned in front of the first
element.
If a collection has been changed since its creation, methods next and
hasNext() may throw a ConcurrentModificationException.
Iterators with this behavior are called fail-fast iterators.
Type parameter E: the type of object returned by the iterator.
Methods
public abstract boolean hasNext() | Returns whether there are more elements to iterate, i.e. whether the iterator is positioned in front of an element. |
public abstract E next() | Returns the next object in the iteration, i.e. returns the element in front of the iterator and advances the iterator by one position. |
public abstract void remove() | Removes the last object returned by next from the collection. |
Method details
hasNext
public abstract boolean hasNext()Returns whether there are more elements to iterate, i.e. whether the
iterator is positioned in front of an element.
Returns
true if there are more elements, false otherwise.See also
next
public abstract E next()Returns the next object in the iteration, i.e. returns the element in
front of the iterator and advances the iterator by one position.
Returns
the next object.
Throws
NoSuchElementException- if there are no more elements.
See also
remove
public abstract void remove()Removes the last object returned by
next from the collection.
This method can only be called once after next was called.Throws
UnsupportedOperationException- if removing is not supported by the collection being iterated.
IllegalStateException- if
nexthas not been called, orremovehas already been called after the last call tonext.