Package io.netty.handler.codec
Class DelimiterBasedFrameDecoder
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- io.netty.channel.ChannelHandlerAdapter
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- io.netty.channel.ChannelInboundHandlerAdapter
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- io.netty.handler.codec.ByteToMessageDecoder
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- io.netty.handler.codec.DelimiterBasedFrameDecoder
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- All Implemented Interfaces:
ChannelHandler,ChannelInboundHandler
public class DelimiterBasedFrameDecoder extends ByteToMessageDecoder
A decoder that splits the receivedByteBufs by one or more delimiters. It is particularly useful for decoding the frames which ends with a delimiter such asNULor newline characters.Predefined delimiters
Delimitersdefines frequently used delimiters for convenience' sake.Specifying more than one delimiter
DelimiterBasedFrameDecoderallows you to specify more than one delimiter. If more than one delimiter is found in the buffer, it chooses the delimiter which produces the shortest frame. For example, if you have the following data in the buffer:+--------------+ | ABC\nDEF\r\n | +--------------+
aDelimiterBasedFrameDecoder(Delimiters.lineDelimiter()) will choose'\n'as the first delimiter and produce two frames:+-----+-----+ | ABC | DEF | +-----+-----+
rather than incorrectly choosing'\r\n'as the first delimiter:+----------+ | ABC\nDEF | +----------+
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Nested Class Summary
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Nested classes/interfaces inherited from class io.netty.handler.codec.ByteToMessageDecoder
ByteToMessageDecoder.Cumulator
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Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Field Summary
Fields Modifier and Type Field Description private ByteBuf[]delimitersprivate booleandiscardingTooLongFrameprivate booleanfailFastprivate LineBasedFrameDecoderlineBasedDecoderSet only when decoding with "\n" and "\r\n" as the delimiter.private intmaxFrameLengthprivate booleanstripDelimiterprivate inttooLongFrameLength-
Fields inherited from class io.netty.handler.codec.ByteToMessageDecoder
COMPOSITE_CUMULATOR, cumulation, MERGE_CUMULATOR
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Constructor Summary
Constructors Constructor Description DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf delimiter)Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf... delimiters)Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf delimiter)Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf... delimiters)Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf delimiter)Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf... delimiters)Creates a new instance.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected java.lang.Objectdecode(ChannelHandlerContext ctx, ByteBuf buffer)Create a frame out of theByteBufand return it.protected voiddecode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out)Decode the from oneByteBufto an other.private voidfail(long frameLength)private static intindexOf(ByteBuf haystack, ByteBuf needle)Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack.private static booleanisLineBased(ByteBuf[] delimiters)Returns true if the delimiters are "\n" and "\r\n".private booleanisSubclass()Returntrueif the current instance is a subclass of DelimiterBasedFrameDecoderprivate static voidvalidateDelimiter(ByteBuf delimiter)private static voidvalidateMaxFrameLength(int maxFrameLength)-
Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder
actualReadableBytes, callDecode, channelInactive, channelInputClosed, channelRead, channelReadComplete, decodeLast, decodeRemovalReentryProtection, discardSomeReadBytes, expandCumulation, fireChannelRead, fireChannelRead, handlerRemoved, handlerRemoved0, internalBuffer, isSingleDecode, setCumulator, setDiscardAfterReads, setSingleDecode, userEventTriggered
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Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught
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Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, handlerAdded, isSharable
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface io.netty.channel.ChannelHandler
handlerAdded
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Field Detail
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delimiters
private final ByteBuf[] delimiters
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maxFrameLength
private final int maxFrameLength
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stripDelimiter
private final boolean stripDelimiter
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failFast
private final boolean failFast
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discardingTooLongFrame
private boolean discardingTooLongFrame
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tooLongFrameLength
private int tooLongFrameLength
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lineBasedDecoder
private final LineBasedFrameDecoder lineBasedDecoder
Set only when decoding with "\n" and "\r\n" as the delimiter.
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Constructor Detail
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf delimiter)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.delimiter- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf delimiter)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.stripDelimiter- whether the decoded frame should strip out the delimiter or notdelimiter- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf delimiter)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.stripDelimiter- whether the decoded frame should strip out the delimiter or notfailFast- If true, aTooLongFrameExceptionis thrown as soon as the decoder notices the length of the frame will exceed maxFrameLength regardless of whether the entire frame has been read. If false, aTooLongFrameExceptionis thrown after the entire frame that exceeds maxFrameLength has been read.delimiter- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf... delimiters)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.delimiters- the delimiters
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf... delimiters)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.stripDelimiter- whether the decoded frame should strip out the delimiter or notdelimiters- the delimiters
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf... delimiters)Creates a new instance.- Parameters:
maxFrameLength- the maximum length of the decoded frame. ATooLongFrameExceptionis thrown if the length of the frame exceeds this value.stripDelimiter- whether the decoded frame should strip out the delimiter or notfailFast- If true, aTooLongFrameExceptionis thrown as soon as the decoder notices the length of the frame will exceed maxFrameLength regardless of whether the entire frame has been read. If false, aTooLongFrameExceptionis thrown after the entire frame that exceeds maxFrameLength has been read.delimiters- the delimiters
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Method Detail
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isLineBased
private static boolean isLineBased(ByteBuf[] delimiters)
Returns true if the delimiters are "\n" and "\r\n".
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isSubclass
private boolean isSubclass()
Returntrueif the current instance is a subclass of DelimiterBasedFrameDecoder
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decode
protected final void decode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out) throws java.lang.Exception
Description copied from class:ByteToMessageDecoderDecode the from oneByteBufto an other. This method will be called till either the inputByteBufhas nothing to read when return from this method or till nothing was read from the inputByteBuf.- Specified by:
decodein classByteToMessageDecoder- Parameters:
ctx- theChannelHandlerContextwhich thisByteToMessageDecoderbelongs toin- theByteBuffrom which to read dataout- theListto which decoded messages should be added- Throws:
java.lang.Exception- is thrown if an error occurs
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decode
protected java.lang.Object decode(ChannelHandlerContext ctx, ByteBuf buffer) throws java.lang.Exception
Create a frame out of theByteBufand return it.- Parameters:
ctx- theChannelHandlerContextwhich thisByteToMessageDecoderbelongs tobuffer- theByteBuffrom which to read data- Returns:
- frame the
ByteBufwhich represent the frame ornullif no frame could be created. - Throws:
java.lang.Exception
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fail
private void fail(long frameLength)
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indexOf
private static int indexOf(ByteBuf haystack, ByteBuf needle)
Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack. -1 is returned if no needle is found in the haystack.
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validateDelimiter
private static void validateDelimiter(ByteBuf delimiter)
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validateMaxFrameLength
private static void validateMaxFrameLength(int maxFrameLength)
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