Package io.netty.handler.codec.json
Class JsonObjectDecoder
- java.lang.Object
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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.json.JsonObjectDecoder
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- All Implemented Interfaces:
ChannelHandler
,ChannelInboundHandler
public class JsonObjectDecoder extends ByteToMessageDecoder
Splits a byte stream of JSON objects and arrays into individual objects/arrays and passes them up theChannelPipeline
.The byte stream is expected to be in UTF-8 character encoding or ASCII. The current implementation uses direct
byte
tochar
cast and then compares thatchar
to a few low range ASCII characters like {@code '{'}, {@code '['} or {@code '"'}. UTF-8 is not using low range [0..0x7F] byte values for multibyte codepoint representations therefore fully supported by this implementation.This class does not do any real parsing or validation. A sequence of bytes is considered a JSON object/array if it contains a matching number of opening and closing braces/brackets. It's up to a subsequent {@link ChannelHandler} to parse the JSON text into a more usable form i.e. a POJO.
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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 int
idx
private boolean
insideString
private int
lastReaderIndex
private int
maxObjectLength
private int
openBraces
private static int
ST_CORRUPTED
private static int
ST_DECODING_ARRAY_STREAM
private static int
ST_DECODING_NORMAL
private static int
ST_INIT
private int
state
private boolean
streamArrayElements
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Fields inherited from class io.netty.handler.codec.ByteToMessageDecoder
COMPOSITE_CUMULATOR, MERGE_CUMULATOR
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Constructor Summary
Constructors Constructor Description JsonObjectDecoder()
JsonObjectDecoder(boolean streamArrayElements)
JsonObjectDecoder(int maxObjectLength)
JsonObjectDecoder(int maxObjectLength, boolean streamArrayElements)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
decode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out)
Decode the from oneByteBuf
to an other.private void
decodeByte(byte c, ByteBuf in, int idx)
protected ByteBuf
extractObject(ChannelHandlerContext ctx, ByteBuf buffer, int index, int length)
Override this method if you want to filter the json objects/arrays that get passed through the pipeline.private void
initDecoding(byte openingBrace)
private void
reset()
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Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder
actualReadableBytes, callDecode, channelInactive, channelRead, channelReadComplete, decodeLast, discardSomeReadBytes, 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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ST_CORRUPTED
private static final int ST_CORRUPTED
- See Also:
- Constant Field Values
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ST_INIT
private static final int ST_INIT
- See Also:
- Constant Field Values
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ST_DECODING_NORMAL
private static final int ST_DECODING_NORMAL
- See Also:
- Constant Field Values
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ST_DECODING_ARRAY_STREAM
private static final int ST_DECODING_ARRAY_STREAM
- See Also:
- Constant Field Values
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openBraces
private int openBraces
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idx
private int idx
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lastReaderIndex
private int lastReaderIndex
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state
private int state
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insideString
private boolean insideString
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maxObjectLength
private final int maxObjectLength
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streamArrayElements
private final boolean streamArrayElements
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Constructor Detail
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JsonObjectDecoder
public JsonObjectDecoder()
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JsonObjectDecoder
public JsonObjectDecoder(int maxObjectLength)
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JsonObjectDecoder
public JsonObjectDecoder(boolean streamArrayElements)
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JsonObjectDecoder
public JsonObjectDecoder(int maxObjectLength, boolean streamArrayElements)
- Parameters:
maxObjectLength
- maximum number of bytes a JSON object/array may use (including braces and all). Objects exceeding this length are dropped and anTooLongFrameException
is thrown.streamArrayElements
- if set to true and the "top level" JSON object is an array, each of its entries is passed through the pipeline individually and immediately after it was fully received, allowing for arrays with "infinitely" many elements.
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Method Detail
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decode
protected void decode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out) throws java.lang.Exception
Description copied from class:ByteToMessageDecoder
Decode the from oneByteBuf
to an other. This method will be called till either the inputByteBuf
has nothing to read when return from this method or till nothing was read from the inputByteBuf
.- Specified by:
decode
in classByteToMessageDecoder
- Parameters:
ctx
- theChannelHandlerContext
which thisByteToMessageDecoder
belongs toin
- theByteBuf
from which to read dataout
- theList
to which decoded messages should be added- Throws:
java.lang.Exception
- is thrown if an error occurs
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extractObject
protected ByteBuf extractObject(ChannelHandlerContext ctx, ByteBuf buffer, int index, int length)
Override this method if you want to filter the json objects/arrays that get passed through the pipeline.
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decodeByte
private void decodeByte(byte c, ByteBuf in, int idx)
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initDecoding
private void initDecoding(byte openingBrace)
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reset
private void reset()
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