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.handler.codec.memcache.binary;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.channel.ChannelHandlerContext;
20 import io.netty.handler.codec.MessageToByteEncoder;
21 import io.netty.handler.codec.memcache.AbstractMemcacheObjectEncoder;
22 import io.netty.util.internal.UnstableApi;
23
24 /**
25 * A {@link MessageToByteEncoder} that encodes binary memcache messages into bytes.
26 */
27 @UnstableApi
28 public abstract class AbstractBinaryMemcacheEncoder<M extends BinaryMemcacheMessage>
29 extends AbstractMemcacheObjectEncoder<M> {
30
31 /**
32 * Every binary memcache message has at least a 24 bytes header.
33 */
34 private static final int MINIMUM_HEADER_SIZE = 24;
35
36 @Override
37 protected ByteBuf encodeMessage(ChannelHandlerContext ctx, M msg) {
38 ByteBuf buf = ctx.alloc().buffer(MINIMUM_HEADER_SIZE + msg.extrasLength()
39 + msg.keyLength());
40
41 encodeHeader(buf, msg);
42 encodeExtras(buf, msg.extras());
43 encodeKey(buf, msg.key());
44
45 return buf;
46 }
47
48 /**
49 * Encode the extras.
50 *
51 * @param buf the {@link ByteBuf} to write into.
52 * @param extras the extras to encode.
53 */
54 private static void encodeExtras(ByteBuf buf, ByteBuf extras) {
55 if (extras == null || !extras.isReadable()) {
56 return;
57 }
58
59 buf.writeBytes(extras);
60 }
61
62 /**
63 * Encode the key.
64 *
65 * @param buf the {@link ByteBuf} to write into.
66 * @param key the key to encode.
67 */
68 private static void encodeKey(ByteBuf buf, ByteBuf key) {
69 if (key == null || !key.isReadable()) {
70 return;
71 }
72
73 buf.writeBytes(key);
74 }
75
76 /**
77 * Encode the header.
78 * <p/>
79 * This methods needs to be implemented by a sub class because the header is different
80 * for both requests and responses.
81 *
82 * @param buf the {@link ByteBuf} to write into.
83 * @param msg the message to encode.
84 */
85 protected abstract void encodeHeader(ByteBuf buf, M msg);
86
87 }