01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * 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 java.util;
19:
20: /**
21: * An Iterator is used to sequence over a collection of objects.
22: */
23: public interface Iterator<E> {
24: /**
25: * Answers if there are more elements to iterate.
26: *
27: * @return true if there are more elements, false otherwise
28: *
29: * @see #next
30: */
31: public boolean hasNext();
32:
33: /**
34: * Answers the next object in the iteration.
35: *
36: * @return the next object
37: *
38: * @exception NoSuchElementException
39: * when there are no more elements
40: *
41: * @see #hasNext
42: */
43: public E next();
44:
45: /**
46: * Removes the last object returned by <code>next</code> from the
47: * collection.
48: *
49: * @exception UnsupportedOperationException
50: * when removing is not supported by the collection being
51: * iterated
52: * @exception IllegalStateException
53: * when <code>next</code> has not been called, or
54: * <code>remove</code> has already been called after the
55: * last call to <code>next</code>
56: */
57: public void remove();
58: }
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