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1   /*
2    * Copyright 2013 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty.channel.nio;
17  
18  import java.nio.channels.SelectionKey;
19  import java.util.AbstractSet;
20  import java.util.Arrays;
21  import java.util.Iterator;
22  import java.util.NoSuchElementException;
23  import java.util.Objects;
24  
25  final class SelectedSelectionKeySet extends AbstractSet<SelectionKey> {
26  
27      SelectionKey[] keys;
28      int size;
29  
30      SelectedSelectionKeySet() {
31          keys = new SelectionKey[1024];
32      }
33  
34      @Override
35      public boolean add(SelectionKey o) {
36          if (o == null) {
37              return false;
38          }
39  
40          if (size == keys.length) {
41              increaseCapacity();
42          }
43  
44          keys[size++] = o;
45          return true;
46      }
47  
48      @Override
49      public boolean remove(Object o) {
50          return false;
51      }
52  
53      @Override
54      public boolean contains(Object o) {
55          SelectionKey[] array = keys;
56          for (int i = 0, s = size; i < s; i++) {
57              SelectionKey k = array[i];
58              if (k.equals(o)) {
59                  return true;
60              }
61          }
62          return false;
63      }
64  
65      @Override
66      public int size() {
67          return size;
68      }
69  
70      @Override
71      public Iterator<SelectionKey> iterator() {
72          return new Iterator<SelectionKey>() {
73              private int idx;
74  
75              @Override
76              public boolean hasNext() {
77                  return idx < size;
78              }
79  
80              @Override
81              public SelectionKey next() {
82                  if (!hasNext()) {
83                      throw new NoSuchElementException();
84                  }
85                  return keys[idx++];
86              }
87  
88              @Override
89              public void remove() {
90                  throw new UnsupportedOperationException();
91              }
92          };
93      }
94  
95      void reset() {
96          reset(0);
97      }
98  
99      void reset(int start) {
100         Arrays.fill(keys, start, size, null);
101         size = 0;
102     }
103 
104     private void increaseCapacity() {
105         SelectionKey[] newKeys = new SelectionKey[keys.length << 1];
106         System.arraycopy(keys, 0, newKeys, 0, size);
107         keys = newKeys;
108     }
109 }