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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package java.util;
/** {@collect.stats}
* {@description.open}
* An iterator over a collection. {@code Iterator} takes the place of
* {@link Enumeration} in the Java Collections Framework. Iterators
* differ from enumerations in two ways:
*
* <ul>
* <li> Iterators allow the caller to remove elements from the
* underlying collection during the iteration with well-defined
* semantics.
* <li> Method names have been improved.
* </ul>
*
* <p>This interface is a member of the
* <a href="{@docRoot}/../technotes/guides/collections/index.html">
* Java Collections Framework</a>.
* {@description.close}
*
* @author Josh Bloch
* @see Collection
* @see ListIterator
* @see Iterable
* @since 1.2
*/
public interface Iterator<E> {
/** {@collect.stats}
* {@description.open}
* Returns {@code true} if the iteration has more elements.
* (In other words, returns {@code true} if {@link #next} would
* return an element rather than throwing an exception.)
* {@description.close}
*
* @return {@code true} if the iteration has more elements
*/
boolean hasNext();
/** {@collect.stats}
* {@description.open}
* Returns the next element in the iteration.
* {@description.close}
* {@property.open formal:java.util.Iterator_HasNext}
* {@new.open}
* In general, it is recommended to call hasNext() and check the return
* value before calling this method.
* {@new.close}
* {@property.close}
*
* @return the next element in the iteration
* @throws NoSuchElementException if the iteration has no more elements
*/
E next();
/** {@collect.stats}
* {@description.open}
* Removes from the underlying collection the last element returned
* by this iterator (optional operation).
* {@description.close}
* {@property.open formal:java.util.Iterator_RemoveOnce}
* This method can be called
* only once per call to {@link #next}.
* {@new.open}
* If the {@link #next} method has not yet been called, this method cannot be called.
* {@new.close}
* {@property.close}
* {@property.open formal:java.util.Collection_UnsafeIterator formal:java.util.Map_UnsafeIterator}
* 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.
* {@property.close}
*
* @throws UnsupportedOperationException if the {@code remove}
* operation is not supported by this iterator
*
* @throws IllegalStateException if the {@code next} method has not
* yet been called, or the {@code remove} method has already
* been called after the last call to the {@code next}
* method
*/
void remove();
}