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/*
* Copyright 2016 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.string;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.ObjectUtil;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.util.List;
/**
* Apply a line separator to the requested {@link String} and encode it into a {@link ByteBuf}.
* A typical setup for a text-based line protocol in a TCP/IP socket would be:
*
* {@link ChannelPipeline} pipeline = ...;
*
* // Decoders
* pipeline.addLast("frameDecoder", new {@link LineBasedFrameDecoder}(80));
* pipeline.addLast("stringDecoder", new {@link StringDecoder}(CharsetUtil.UTF_8));
*
* // Encoder
* pipeline.addLast("lineEncoder", new {@link LineEncoder}(LineSeparator.UNIX, CharsetUtil.UTF_8));
*
* and then you can use a {@link String} instead of a {@link ByteBuf}
* as a message:
*
* void channelRead({@link ChannelHandlerContext} ctx, {@link String} msg) {
* ch.write("Did you say '" + msg + "'?");
* }
*
*/
@Sharable
public class LineEncoder extends MessageToMessageEncoder {
private final Charset charset;
private final byte[] lineSeparator;
/**
* Creates a new instance with the current system line separator and UTF-8 charset encoding.
*/
public LineEncoder() {
this(LineSeparator.DEFAULT, CharsetUtil.UTF_8);
}
/**
* Creates a new instance with the specified line separator and UTF-8 charset encoding.
*/
public LineEncoder(LineSeparator lineSeparator) {
this(lineSeparator, CharsetUtil.UTF_8);
}
/**
* Creates a new instance with the specified character set.
*/
public LineEncoder(Charset charset) {
this(LineSeparator.DEFAULT, charset);
}
/**
* Creates a new instance with the specified line separator and character set.
*/
public LineEncoder(LineSeparator lineSeparator, Charset charset) {
this.charset = ObjectUtil.checkNotNull(charset, "charset");
this.lineSeparator = ObjectUtil.checkNotNull(lineSeparator, "lineSeparator").value().getBytes(charset);
}
@Override
protected void encode(ChannelHandlerContext ctx, CharSequence msg, List