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 * 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.handler.codec;
17
18 import static io.netty.util.internal.ObjectUtil.checkNotNull;
19
20 /**
21 * Result of detecting a protocol.
22 *
23 * @param <T> the type of the protocol
24 */
25 public final class ProtocolDetectionResult<T> {
26
27 @SuppressWarnings({ "rawtypes", "unchecked" })
28 private static final ProtocolDetectionResult NEEDS_MORE_DATA =
29 new ProtocolDetectionResult(ProtocolDetectionState.NEEDS_MORE_DATA, null);
30 @SuppressWarnings({ "rawtypes", "unchecked" })
31 private static final ProtocolDetectionResult INVALID =
32 new ProtocolDetectionResult(ProtocolDetectionState.INVALID, null);
33
34 private final ProtocolDetectionState state;
35 private final T result;
36
37 /**
38 * Returns a {@link ProtocolDetectionResult} that signals that more data is needed to detect the protocol.
39 */
40 @SuppressWarnings("unchecked")
41 public static <T> ProtocolDetectionResult<T> needsMoreData() {
42 return NEEDS_MORE_DATA;
43 }
44
45 /**
46 * Returns a {@link ProtocolDetectionResult} that signals the data was invalid for the protocol.
47 */
48 @SuppressWarnings("unchecked")
49 public static <T> ProtocolDetectionResult<T> invalid() {
50 return INVALID;
51 }
52
53 /**
54 * Returns a {@link ProtocolDetectionResult} which holds the detected protocol.
55 */
56 @SuppressWarnings("unchecked")
57 public static <T> ProtocolDetectionResult<T> detected(T protocol) {
58 return new ProtocolDetectionResult<T>(ProtocolDetectionState.DETECTED, checkNotNull(protocol, "protocol"));
59 }
60
61 private ProtocolDetectionResult(ProtocolDetectionState state, T result) {
62 this.state = state;
63 this.result = result;
64 }
65
66 /**
67 * Return the {@link ProtocolDetectionState}. If the state is {@link ProtocolDetectionState#DETECTED} you
68 * can retrieve the protocol via {@link #detectedProtocol()}.
69 */
70 public ProtocolDetectionState state() {
71 return state;
72 }
73
74 /**
75 * Returns the protocol if {@link #state()} returns {@link ProtocolDetectionState#DETECTED}, otherwise {@code null}.
76 */
77 public T detectedProtocol() {
78 return result;
79 }
80 }