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1   /*
2    * Copyright 2015 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    *   http://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  
17  package io.netty.resolver.dns;
18  
19  import java.net.InetSocketAddress;
20  
21  final class SequentialDnsServerAddressStream implements DnsServerAddressStream {
22  
23      private final InetSocketAddress[] addresses;
24      private int i;
25  
26      SequentialDnsServerAddressStream(InetSocketAddress[] addresses, int startIdx) {
27          this.addresses = addresses;
28          i = startIdx;
29      }
30  
31      @Override
32      public InetSocketAddress next() {
33          int i = this.i;
34          InetSocketAddress next = addresses[i];
35          if (++ i < addresses.length) {
36              this.i = i;
37          } else {
38              this.i = 0;
39          }
40          return next;
41      }
42  
43      @Override
44      public int size() {
45          return addresses.length;
46      }
47  
48      @Override
49      public SequentialDnsServerAddressStream duplicate() {
50          return new SequentialDnsServerAddressStream(addresses, i);
51      }
52  
53      @Override
54      public String toString() {
55          return toString("sequential", i, addresses);
56      }
57  
58      static String toString(String type, int index, InetSocketAddress[] addresses) {
59          final StringBuilder buf = new StringBuilder(type.length() + 2 + addresses.length * 16);
60          buf.append(type).append("(index: ").append(index);
61          buf.append(", addrs: (");
62          for (InetSocketAddress a: addresses) {
63              buf.append(a).append(", ");
64          }
65  
66          buf.setLength(buf.length() - 2);
67          buf.append("))");
68  
69          return buf.toString();
70      }
71  }