io.netty.handler.codec.MessageToByteEncoder Maven / Gradle / Ivy
/*
* Copyright 2012 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:
*
* http://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;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.MessageBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOutboundMessageHandlerAdapter;
/**
* {@link ChannelOutboundMessageHandlerAdapter} which encodes message in a stream-like fashion from one message to an
* {@link ByteBuf}.
*
*
* Example implementation which encodes {@link Integer}s to a {@link ByteBuf}.
*
*
* public class IntegerEncoder extends {@link MessageToByteEncoder}<{@link Integer}> {
* {@code @Override}
* public void encode({@link ChannelHandlerContext} ctx, {@link Integer} msg, {@link ByteBuf} out)
* throws {@link Exception} {
* out.writeInt(msg);
* }
* }
*
*/
public abstract class MessageToByteEncoder extends ChannelOutboundMessageHandlerAdapter {
@Override
public void flush(ChannelHandlerContext ctx, I msg) throws Exception {
try {
encode(ctx, msg, ctx.nextOutboundByteBuffer());
} catch (CodecException e) {
throw e;
} catch (Exception e) {
throw new CodecException(e);
}
}
/**
* Encode a message into a {@link ByteBuf}. This method will be called till the {@link MessageBuf} has
* nothing left.
*
* @param ctx the {@link ChannelHandlerContext} which this {@link MessageToByteEncoder} belongs to
* @param msg the message to encode
* @param out the {@link ByteBuf} into which the encoded message will be written
* @throws Exception is thrown if an error accour
*/
protected abstract void encode(ChannelHandlerContext ctx, I msg, ByteBuf out) throws Exception;
}