Class StringDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

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

io.netty.handler.codec.string.StringDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler

@Sharable
public class StringDecoder
extends MessageToMessageDecoder<ByteBuf>

Decodes a received ByteBuf into a String. Please note that this decoder must be used with a proper ByteToMessageDecoder such as DelimiterBasedFrameDecoder or LineBasedFrameDecoder 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 LineBasedFrameDecoder(80));
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 channelRead(ChannelHandlerContext ctx, String msg) {
    ch.write("Did you say '" + msg + "'?\n");
}

Nested Class Summary

Nested classes/interfaces inherited from interface ChannelHandler

ChannelHandler.Sharable

Modifier and Type	Interface	Description
static @interface	ChannelHandler.Sharable	Indicates that the same instance of the annotated ChannelHandler can be added to one or more ChannelPipelines multiple times without a race condition.

Constructor Summary

Constructors

Constructor	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

Modifier and Type	Method	Description
protected void	decode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out)	Decode from one message to an other.

Methods inherited from class MessageToMessageDecoder

acceptInboundMessage, channelRead, channelReadComplete

Modifier and Type	Method	Description
boolean	acceptInboundMessage(Object msg)	Returns true if the given message should be handled.
void	channelRead(ChannelHandlerContext ctx, Object msg)	Calls ChannelHandlerContext.fireChannelRead(Object) to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelReadComplete(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelReadComplete() to forward to the next ChannelInboundHandler in the ChannelPipeline.

Methods inherited from class ChannelInboundHandlerAdapter

channelActive, channelInactive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught, userEventTriggered

Modifier and Type	Method	Description
void	channelActive(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelActive() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelInactive(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelInactive() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelRegistered(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelRegistered() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelUnregistered(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelUnregistered() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	channelWritabilityChanged(ChannelHandlerContext ctx)	Calls ChannelHandlerContext.fireChannelWritabilityChanged() to forward to the next ChannelInboundHandler in the ChannelPipeline.
void	exceptionCaught(ChannelHandlerContext ctx, Throwable cause)	Calls ChannelHandlerContext.fireExceptionCaught(Throwable) to forward to the next ChannelHandler in the ChannelPipeline.
void	userEventTriggered(ChannelHandlerContext ctx, Object evt)	Calls ChannelHandlerContext.fireUserEventTriggered(Object) to forward to the next ChannelInboundHandler in the ChannelPipeline.

Methods inherited from class ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

Modifier and Type	Method	Description
protected void	ensureNotSharable()	Throws IllegalStateException if ChannelHandlerAdapter.isSharable() returns true
void	handlerAdded(ChannelHandlerContext ctx)	Do nothing by default, sub-classes may override this method.
void	handlerRemoved(ChannelHandlerContext ctx)	Do nothing by default, sub-classes may override this method.
boolean	isSharable()	Return true if the implementation is ChannelHandler.Sharable and so can be added to different ChannelPipelines.

Methods inherited from class Object

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

Constructor Details

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 Details

decode

protected void decode(ChannelHandlerContext ctx,
 ByteBuf msg,
 List<Object> out)
               throws Exception

Description copied from class: MessageToMessageDecoder

Decode from one message to an other. This method will be called for each written message that can be handled by this decoder.

Specified by:

decode in class MessageToMessageDecoder<ByteBuf>

Parameters:

ctx - the ChannelHandlerContext which this MessageToMessageDecoder belongs to

msg - the message to decode to an other one

out - the List to which decoded messages should be added

Throws:

Exception - is thrown if an error occurs