io.netty.handler.codec.string

Class StringDecoder

java.lang.Object

io.netty.channel.ChannelStateHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.handler.codec.MessageToMessageDecoder<ByteBuf,String>

io.netty.handler.codec.string.StringDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler, ChannelInboundMessageHandler<ByteBuf>, ChannelStateHandler

@ChannelHandler.Sharable
public class StringDecoder
extends MessageToMessageDecoder<ByteBuf,String>

Decodes a received ByteBuf into a String. Please note that this decoder must be used with a proper FrameDecoder such as DelimiterBasedFrameDecoder if you are using a stream-based transport such as TCP/IP. A typical setup for a text-based line protocol in a TCP/IP socket would be:

 ChannelPipeline pipeline = ...;

 // Decoders
 pipeline.addLast("frameDecoder", new DelimiterBasedFrameDecoder(80, Delimiters.lineDelimiter()));
 pipeline.addLast("stringDecoder", new StringDecoder(CharsetUtil.UTF_8));

 // Encoder
 pipeline.addLast("stringEncoder", new StringEncoder(CharsetUtil.UTF_8));
 

and then you can use a String instead of a ByteBuf as a message:

 void messageReceived(ChannelHandlerContext ctx, MessageEvent e) {
     String msg = (String) e.getMessage();
     ch.write("Did you say '" + msg + "'?\n");
 }
 

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor and Description
StringDecoder() Creates a new instance with the current system character set.
StringDecoder(Charset charset) Creates a new instance with the specified character set.

Method Summary

Methods

Modifier and Type	Method and Description
String	decode(ChannelHandlerContext ctx, ByteBuf msg)
boolean	isDecodable(Object msg) Returns true if and only if the specified message can be decoded by this decoder.

Methods inherited from class io.netty.handler.codec.MessageToMessageDecoder

inboundBufferUpdated, newInboundBuffer

Methods inherited from class io.netty.channel.ChannelStateHandlerAdapter

afterAdd, afterRemove, beforeAdd, beforeRemove, channelActive, channelInactive, channelRegistered, channelUnregistered, exceptionCaught, userEventTriggered

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelStateHandler

channelActive, channelInactive, channelRegistered, channelUnregistered

Methods inherited from interface io.netty.channel.ChannelHandler

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught, userEventTriggered

Constructor Detail

StringDecoder

public StringDecoder()

Creates a new instance with the current system character set.

StringDecoder

public StringDecoder(Charset charset)

Creates a new instance with the specified character set.

Method Detail

isDecodable

public boolean isDecodable(Object msg)
                    throws Exception

Description copied from class: MessageToMessageDecoder

Returns true if and only if the specified message can be decoded by this decoder.

Overrides:

isDecodable in class MessageToMessageDecoder<ByteBuf,String>

Parameters:

msg - the message

Throws:

Exception

decode

public String decode(ChannelHandlerContext ctx,
            ByteBuf msg)
              throws Exception

Specified by:

decode in class MessageToMessageDecoder<ByteBuf,String>

Throws:

Exception