Class DelimiterBasedFrameDecoder
java.lang.Object
org.jboss.netty.channel.SimpleChannelUpstreamHandler
org.jboss.netty.handler.codec.frame.FrameDecoder
org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder
- All Implemented Interfaces:
ChannelHandler
,ChannelUpstreamHandler
,LifeCycleAwareChannelHandler
A decoder that splits the received
ChannelBuffer
s by one or more
delimiters. It is particularly useful for decoding the frames which ends
with a delimiter such as NUL
or
newline characters.
Predefined delimiters
Delimiters
defines frequently used delimiters for convenience' sake.
Specifying more than one delimiter
DelimiterBasedFrameDecoder
allows 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 | +--------------+a
DelimiterBasedFrameDecoder
(
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
Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final ChannelBuffer[]
private boolean
private final boolean
private final LineBasedFrameDecoder
Set only when decoding with "\n" and "\r\n" as the delimiter.private final int
private final boolean
private int
Fields inherited from class org.jboss.netty.handler.codec.frame.FrameDecoder
cumulation, DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS
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Constructor Summary
ConstructorsConstructorDescriptionDelimiterBasedFrameDecoder
(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer delimiter) Creates a new instance.DelimiterBasedFrameDecoder
(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer... delimiters) Creates a new instance.DelimiterBasedFrameDecoder
(int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter) Creates a new instance.DelimiterBasedFrameDecoder
(int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters) Creates a new instance.DelimiterBasedFrameDecoder
(int maxFrameLength, ChannelBuffer delimiter) Creates a new instance.DelimiterBasedFrameDecoder
(int maxFrameLength, ChannelBuffer... delimiters) Creates a new instance. -
Method Summary
Modifier and TypeMethodDescriptionprotected Object
decode
(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) Decodes the received packets so far into a frame.private void
fail
(ChannelHandlerContext ctx, long frameLength) private static int
indexOf
(ChannelBuffer haystack, ChannelBuffer needle) Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack.private static boolean
isLineBased
(ChannelBuffer[] delimiters) Returns true if the delimiters are "\n" and "\r\n".private boolean
Returntrue
if the current instance is a subclass of DelimiterBasedFrameDecoderprivate static void
validateDelimiter
(ChannelBuffer delimiter) private static void
validateMaxFrameLength
(int maxFrameLength) Methods inherited from class org.jboss.netty.handler.codec.frame.FrameDecoder
actualReadableBytes, afterAdd, afterRemove, appendToCumulation, beforeAdd, beforeRemove, channelClosed, channelDisconnected, cleanup, decodeLast, exceptionCaught, extractFrame, getMaxCumulationBufferCapacity, getMaxCumulationBufferComponents, internalBuffer, isUnfold, messageReceived, newCumulationBuffer, replace, setMaxCumulationBufferCapacity, setMaxCumulationBufferComponents, setUnfold, unfoldAndFireMessageReceived, updateCumulation
Methods inherited from class org.jboss.netty.channel.SimpleChannelUpstreamHandler
channelBound, channelConnected, channelInterestChanged, channelOpen, channelUnbound, childChannelClosed, childChannelOpen, handleUpstream, writeComplete
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Field Details
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delimiters
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maxFrameLength
private final int maxFrameLength -
stripDelimiter
private final boolean stripDelimiter -
failFast
private final boolean failFast -
discardingTooLongFrame
private boolean discardingTooLongFrame -
tooLongFrameLength
private int tooLongFrameLength -
lineBasedDecoder
Set only when decoding with "\n" and "\r\n" as the delimiter.
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Constructor Details
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DelimiterBasedFrameDecoder
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.delimiter
- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter) Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is 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, ChannelBuffer delimiter) Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notfailFast
- If true, aTooLongFrameException
is 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, aTooLongFrameException
is thrown after the entire frame that exceeds maxFrameLength has been read.delimiter
- the delimiter
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DelimiterBasedFrameDecoder
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.delimiters
- the delimiters
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters) Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is 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, ChannelBuffer... delimiters) Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notfailFast
- If true, aTooLongFrameException
is 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, aTooLongFrameException
is thrown after the entire frame that exceeds maxFrameLength has been read.delimiters
- the delimiters
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Method Details
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isLineBased
Returns true if the delimiters are "\n" and "\r\n". -
isSubclass
private boolean isSubclass()Returntrue
if the current instance is a subclass of DelimiterBasedFrameDecoder -
decode
protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws Exception Description copied from class:FrameDecoder
Decodes the received packets so far into a frame. If an sub-class wants to extract a frame out of the buffer it should use theFrameDecoder.extractFrame(ChannelBuffer, int, int)
method, to make optimizations easier later.- Specified by:
decode
in classFrameDecoder
- Parameters:
ctx
- the context of this handlerchannel
- the current channelbuffer
- the cumulative buffer of received packets so far. Note that the buffer might be empty, which means you should not make an assumption that the buffer contains at least one byte in your decoder implementation.- Returns:
- the decoded frame if a full frame was received and decoded.
null
if there's not enough data in the buffer to decode a frame. - Throws:
Exception
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fail
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indexOf
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. -
validateDelimiter
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validateMaxFrameLength
private static void validateMaxFrameLength(int maxFrameLength)
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