1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.io.function;
19
20 import java.io.IOException;
21 import java.io.UncheckedIOException;
22 import java.util.Iterator;
23 import java.util.NoSuchElementException;
24 import java.util.Objects;
25 import java.util.function.Consumer;
26
27 /**
28 * Like {@link Iterator} but throws {@link IOException}.
29 *
30 * @param <E> the type of elements returned by this iterator.
31 * @since 2.12.0
32 */
33 public interface IOIterator<E> {
34
35 /**
36 * Adapts the given Iterator as an IOIterator.
37 *
38 * @param <E> the type of the stream elements.
39 * @param iterator The iterator to adapt
40 * @return A new IOIterator
41 */
42 static <E> IOIterator<E> adapt(final Iterator<E> iterator) {
43 return IOIteratorAdapter.adapt(iterator);
44 }
45
46 /**
47 * Creates an {@link Iterator} for this instance that throws {@link UncheckedIOException} instead of
48 * {@link IOException}.
49 *
50 * @return an {@link UncheckedIOException} {@link Iterator}.
51 */
52 default Iterator<E> asIterator() {
53 return new UncheckedIOIterator<>(this);
54 }
55
56 /**
57 * Like {@link Iterator#forEachRemaining(Consumer)}.
58 *
59 * @param action See delegate.
60 * @throws IOException if an I/O error occurs.
61 */
62 default void forEachRemaining(final IOConsumer<? super E> action) throws IOException {
63 Objects.requireNonNull(action);
64 while (hasNext()) {
65 action.accept(next());
66 }
67 }
68
69 /**
70 * Like {@link Iterator#hasNext()}.
71 *
72 * @return See delegate.
73 * @throws IOException if an I/O error occurs.
74 */
75 boolean hasNext() throws IOException;
76
77 /**
78 * Like {@link Iterator#next()}.
79 *
80 * @return See delegate.
81 * @throws IOException if an I/O error occurs.
82 * @throws NoSuchElementException if the iteration has no more elements
83 */
84 E next() throws IOException;
85
86 /**
87 * Like {@link Iterator#remove()}.
88 *
89 * @throws IOException if an I/O error occurs.
90 */
91 @SuppressWarnings("unused")
92 default void remove() throws IOException {
93 unwrap().remove();
94 }
95
96 /**
97 * Unwraps this instance and returns the underlying {@link Iterator}.
98 * <p>
99 * Implementations may not have anything to unwrap and that behavior is undefined for now.
100 * </p>
101 * @return the underlying Iterator.
102 */
103 Iterator<E> unwrap();
104
105 }