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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  package org.apache.commons.geometry.core.internal;
18  
19  import java.util.ArrayList;
20  import java.util.Arrays;
21  import java.util.Collections;
22  import java.util.Iterator;
23  import java.util.List;
24  import java.util.NoSuchElementException;
25  
26  import org.junit.jupiter.api.Assertions;
27  import org.junit.jupiter.api.Test;
28  
29  class IteratorTransformTest {
30  
31      @Test
32      void testIteration() {
33          // arrange
34          final List<Integer> input = Arrays.asList(1, 2, 3, 4, 12, 13);
35  
36          // act
37          final List<String> result = toList(new EvenCharIterator(input.iterator()));
38  
39          // assert
40          Assertions.assertEquals(Arrays.asList("2", "4", "1", "2"), result);
41      }
42  
43      @Test
44      void testThrowsNoSuchElement() {
45          // arrange
46          final List<Integer> input = Collections.emptyList();
47          final EvenCharIterator it = new EvenCharIterator(input.iterator());
48  
49          // act/assert
50          Assertions.assertFalse(it.hasNext());
51          Assertions.assertThrows(NoSuchElementException.class, it::next);
52      }
53  
54      private static <T> List<T> toList(final Iterator<T> it) {
55          final List<T> result = new ArrayList<>();
56          while (it.hasNext()) {
57              result.add(it.next());
58          }
59  
60          return result;
61      }
62  
63      private static class EvenCharIterator extends IteratorTransform<Integer, String> {
64  
65          EvenCharIterator(final Iterator<Integer> inputIterator) {
66              super(inputIterator);
67          }
68  
69          /** {@inheritDoc} */
70          @Override
71          protected void acceptInput(final Integer input) {
72              // filter out odd integers
73              final int value = input;
74              if (value % 2 == 0) {
75                  final char[] chars = (Integer.toString(value)).toCharArray();
76  
77                  if (chars.length > 1) {
78                      final List<String> strs = new ArrayList<>();
79                      for (final char ch : chars) {
80                          strs.add(String.valueOf(ch));
81                      }
82  
83                      addAllOutput(strs);
84                  } else if (chars.length == 1) {
85                      addOutput(String.valueOf(chars[0]));
86                  }
87              }
88          }
89      }
90  }