Class FixedLengthFrameDecoder
java.lang.Object
org.jboss.netty.channel.SimpleChannelUpstreamHandler
org.jboss.netty.handler.codec.frame.FrameDecoder
org.jboss.netty.handler.codec.frame.FixedLengthFrameDecoder
- All Implemented Interfaces:
ChannelHandler
,ChannelUpstreamHandler
,LifeCycleAwareChannelHandler
A decoder that splits the received
ChannelBuffer
s by the fixed number
of bytes. For example, if you received the following four fragmented packets:
+---+----+------+----+ | A | BC | DEFG | HI | +---+----+------+----+A
FixedLengthFrameDecoder
(3)
will decode them into the
following three packets with the fixed length:
+-----+-----+-----+ | ABC | DEF | GHI | +-----+-----+-----+
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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 boolean
private final int
Fields inherited from class org.jboss.netty.handler.codec.frame.FrameDecoder
cumulation, DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS
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Constructor Summary
ConstructorsConstructorDescriptionFixedLengthFrameDecoder
(int frameLength) CallsFixedLengthFrameDecoder(int, boolean)
withfalse
FixedLengthFrameDecoder
(int frameLength, boolean allocateFullBuffer) 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.protected ChannelBuffer
newCumulationBuffer
(ChannelHandlerContext ctx, int minimumCapacity) Create a newChannelBuffer
which is used for the cumulation.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, 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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frameLength
private final int frameLength -
allocateFullBuffer
private final boolean allocateFullBuffer
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Constructor Details
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FixedLengthFrameDecoder
public FixedLengthFrameDecoder(int frameLength) CallsFixedLengthFrameDecoder(int, boolean)
withfalse
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FixedLengthFrameDecoder
public FixedLengthFrameDecoder(int frameLength, boolean allocateFullBuffer) Creates a new instance.- Parameters:
frameLength
- the length of the frameallocateFullBuffer
-true
if the cumulativeChannelBuffer
should use theframeLength
as its initial size
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Method Details
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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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newCumulationBuffer
Description copied from class:FrameDecoder
Create a newChannelBuffer
which is used for the cumulation. Sub-classes may override this.- Overrides:
newCumulationBuffer
in classFrameDecoder
- Parameters:
ctx
-ChannelHandlerContext
for this handler- Returns:
- buffer the
ChannelBuffer
which is used for cumulation
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