io.netty.handler.codec.protobuf.ProtobufEncoder Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package io.netty.handler.codec.protobuf;
import com.google.protobuf.Message;
import com.google.protobuf.MessageLite;
import com.google.protobuf.MessageLiteOrBuilder;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.MessageToMessageEncoder;
import java.util.List;
import static io.netty.buffer.Unpooled.*;
/**
* Encodes the requested Google
* Protocol Buffers {@link Message} and {@link MessageLite} into a
* {@link ByteBuf}. A typical setup for TCP/IP would be:
*
* {@link ChannelPipeline} pipeline = ...;
*
* // Decoders
* pipeline.addLast("frameDecoder",
* new {@link LengthFieldBasedFrameDecoder}(1048576, 0, 4, 0, 4));
* pipeline.addLast("protobufDecoder",
* new {@link ProtobufDecoder}(MyMessage.getDefaultInstance()));
*
* // Encoder
* pipeline.addLast("frameEncoder", new {@link LengthFieldPrepender}(4));
* pipeline.addLast("protobufEncoder", new {@link ProtobufEncoder}());
*
* and then you can use a {@code MyMessage} instead of a {@link ByteBuf}
* as a message:
*
* void channelRead({@link ChannelHandlerContext} ctx, Object msg) {
* MyMessage req = (MyMessage) msg;
* MyMessage res = MyMessage.newBuilder().setText(
* "Did you say '" + req.getText() + "'?").build();
* ch.write(res);
* }
*
*/
@Sharable
public class ProtobufEncoder extends MessageToMessageEncoder {
@Override
protected void encode(ChannelHandlerContext ctx, MessageLiteOrBuilder msg, List