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;
17
18 import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
19
20 import io.netty.buffer.ByteBuf;
21 import io.netty.buffer.ByteBufHolder;
22
23 /**
24 * Default {@link MessageSizeEstimator} implementation which supports the estimation of the size of
25 * {@link ByteBuf}, {@link ByteBufHolder} and {@link FileRegion}.
26 */
27 public final class DefaultMessageSizeEstimator implements MessageSizeEstimator {
28
29 private static final class HandleImpl implements Handle {
30 private final int unknownSize;
31
32 private HandleImpl(int unknownSize) {
33 this.unknownSize = unknownSize;
34 }
35
36 @Override
37 public int size(Object msg) {
38 if (msg instanceof ByteBuf) {
39 return ((ByteBuf) msg).readableBytes();
40 }
41 if (msg instanceof ByteBufHolder) {
42 return ((ByteBufHolder) msg).content().readableBytes();
43 }
44 if (msg instanceof FileRegion) {
45 return 0;
46 }
47 return unknownSize;
48 }
49 }
50
51 /**
52 * Return the default implementation which returns {@code 8} for unknown messages.
53 */
54 public static final MessageSizeEstimator DEFAULT = new DefaultMessageSizeEstimator(8);
55
56 private final Handle handle;
57
58 /**
59 * Create a new instance
60 *
61 * @param unknownSize The size which is returned for unknown messages.
62 */
63 public DefaultMessageSizeEstimator(int unknownSize) {
64 checkPositiveOrZero(unknownSize, "unknownSize");
65 handle = new HandleImpl(unknownSize);
66 }
67
68 @Override
69 public Handle newHandle() {
70 return handle;
71 }
72 }