| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.util; |
| |
| /** |
| * An {@code 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 {@code next} and |
| * {@code hasNext()} may throw a {@code ConcurrentModificationException}. |
| * Iterators with this behavior are called fail-fast iterators. |
| * |
| * @param <E> |
| * the type of object returned by the iterator. |
| */ |
| public interface Iterator<E> { |
| /** |
| * Returns whether there are more elements to iterate, i.e. whether the |
| * iterator is positioned in front of an element. |
| * |
| * @return {@code true} if there are more elements, {@code false} otherwise. |
| * @see #next |
| */ |
| public boolean hasNext(); |
| |
| /** |
| * Returns the next object in the iteration, i.e. returns the element in |
| * front of the iterator and advances the iterator by one position. |
| * |
| * @return the next object. |
| * @throws NoSuchElementException |
| * if there are no more elements. |
| * @see #hasNext |
| */ |
| public E next(); |
| |
| /** |
| * Removes the last object returned by {@code next} from the collection. |
| * This method can only be called once after {@code next} was called. |
| * |
| * @throws UnsupportedOperationException |
| * if removing is not supported by the collection being |
| * iterated. |
| * @throws IllegalStateException |
| * if {@code next} has not been called, or {@code remove} has |
| * already been called after the last call to {@code next}. |
| */ |
| public void remove(); |
| } |