Netty/Codec 4.1.107.Final · io.netty.handler.codec.LengthFieldPrepender

An encoder that prepends the length of the message. The length value is prepended as a binary form.

For example, LengthFieldPrepender(2) will encode the following 12-bytes string:

+----------------+
| "HELLO, WORLD" |
+----------------+

into the following:

+--------+----------------+
+ 0x000C | "HELLO, WORLD" |
+--------+----------------+

If you turned on the lengthIncludesLengthFieldLength flag in the constructor, the encoded data would look like the following (12 (original data) + 2 (prepended data) = 14 (0xE)):

+--------+----------------+
+ 0x000E | "HELLO, WORLD" |
+--------+----------------+

Modifier and Type	Field and Description
private final ByteOrder	byteOrder
private final int	lengthAdjustment
private final int	lengthFieldLength
private final boolean	lengthIncludesLengthFieldLength

Constructor Summary

Access	Constructor and Description
public	LengthFieldPrepender(int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthFieldLength) Creates a new instance.
public	LengthFieldPrepender(int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthFieldLength, boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. lengthIncludesLengthFieldLength) Creates a new instance.
public	LengthFieldPrepender(int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthFieldLength, int the compensation value to add to the value of the length field lengthAdjustment) Creates a new instance.
public	LengthFieldPrepender(int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthFieldLength, int the compensation value to add to the value of the length field lengthAdjustment, boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. lengthIncludesLengthFieldLength) Creates a new instance.
public	LengthFieldPrepender(ByteOrder the `ByteOrder` of the length field byteOrder, int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthFieldLength, int the compensation value to add to the value of the length field lengthAdjustment, boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. lengthIncludesLengthFieldLength) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
protected void	encode(ChannelHandlerContext the `ChannelHandlerContext` which this `MessageToMessageEncoder` belongs to ctx, ByteBuf the message to encode to an other one msg, List<Object> the `List` into which the encoded msg should be added needs to do some kind of aggregation out) Implements abstract io.netty.handler.codec.MessageToMessageEncoder.encode. Encode from one message to an other.

Inherited from io.netty.handler.codec.MessageToMessageEncoder:: acceptOutboundMessage write

Field Detail

byteOrder	back to summary
private final ByteOrder byteOrder

lengthAdjustment	back to summary
private final int lengthAdjustment

lengthFieldLength	back to summary
private final int lengthFieldLength

lengthIncludesLengthFieldLength	back to summary
private final boolean lengthIncludesLengthFieldLength

Constructor Detail

LengthFieldPrepender back to summary

LengthFieldPrepender	back to summary
public LengthFieldPrepender(int lengthFieldLength) Creates a new instance. Parameters lengthFieldLength:int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. Exceptions IllegalArgumentException: if `lengthFieldLength` is not 1, 2, 3, 4, or 8

public LengthFieldPrepender(int lengthFieldLength)

Creates a new instance.

Parameters

lengthFieldLength:int: the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed.

Exceptions

IllegalArgumentException:: if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender back to summary

LengthFieldPrepender	back to summary
public LengthFieldPrepender(int lengthFieldLength, boolean lengthIncludesLengthFieldLength) Creates a new instance. Parameters lengthFieldLength:int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthIncludesLengthFieldLength:boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. Exceptions IllegalArgumentException: if `lengthFieldLength` is not 1, 2, 3, 4, or 8

public LengthFieldPrepender(int lengthFieldLength, boolean lengthIncludesLengthFieldLength)

Creates a new instance.

Parameters

lengthFieldLength:int: the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed.
lengthIncludesLengthFieldLength:boolean: if true, the length of the prepended length field is added to the value of the prepended length field.

Exceptions

IllegalArgumentException:: if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender back to summary

LengthFieldPrepender	back to summary
public LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment) Creates a new instance. Parameters lengthFieldLength:int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthAdjustment:int the compensation value to add to the value of the length field Exceptions IllegalArgumentException: if `lengthFieldLength` is not 1, 2, 3, 4, or 8

public LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment)

Creates a new instance.

Parameters

lengthFieldLength:int: the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed.
lengthAdjustment:int: the compensation value to add to the value of the length field

Exceptions

IllegalArgumentException:: if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender back to summary

LengthFieldPrepender	back to summary
public LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength) Creates a new instance. Parameters lengthFieldLength:int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthAdjustment:int the compensation value to add to the value of the length field lengthIncludesLengthFieldLength:boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. Exceptions IllegalArgumentException: if `lengthFieldLength` is not 1, 2, 3, 4, or 8

public LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength)

Creates a new instance.

Parameters

lengthFieldLength:int: the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed.
lengthAdjustment:int: the compensation value to add to the value of the length field
lengthIncludesLengthFieldLength:boolean: if true, the length of the prepended length field is added to the value of the prepended length field.

Exceptions

IllegalArgumentException:: if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender back to summary

LengthFieldPrepender	back to summary
public LengthFieldPrepender(ByteOrder byteOrder, int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength) Creates a new instance. Parameters byteOrder:ByteOrder the `ByteOrder` of the length field lengthFieldLength:int the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed. lengthAdjustment:int the compensation value to add to the value of the length field lengthIncludesLengthFieldLength:boolean if `true`, the length of the prepended length field is added to the value of the prepended length field. Exceptions IllegalArgumentException: if `lengthFieldLength` is not 1, 2, 3, 4, or 8

public LengthFieldPrepender(ByteOrder byteOrder, int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength)

Creates a new instance.

Parameters

byteOrder:ByteOrder: the ByteOrder of the length field
lengthFieldLength:int: the length of the prepended length field. Only 1, 2, 3, 4, and 8 are allowed.
lengthAdjustment:int: the compensation value to add to the value of the length field
lengthIncludesLengthFieldLength:boolean: if true, the length of the prepended length field is added to the value of the prepended length field.

Exceptions

IllegalArgumentException:: if lengthFieldLength is not 1, 2, 3, 4, or 8

Method Detail

encode back to summary

encode	back to summary
protected void encode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) throws Exception Implements abstract io.netty.handler.codec.MessageToMessageEncoder.encode. Doc from io.netty.handler.codec.MessageToMessageEncoder.encode. Encode from one message to an other. This method will be called for each written message that can be handled by this encoder. Parameters ctx:ChannelHandlerContext the `ChannelHandlerContext` which this `MessageToMessageEncoder` belongs to msg:ByteBuf the message to encode to an other one out:List<Object> the `List` into which the encoded msg should be added needs to do some kind of aggregation Annotations @Override Exceptions Exception: is thrown if an error occurs

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

Implements abstract io.netty.handler.codec.MessageToMessageEncoder.encode.

Doc from io.netty.handler.codec.MessageToMessageEncoder.encode.

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

Parameters

ctx:ChannelHandlerContext: the ChannelHandlerContext which this MessageToMessageEncoder belongs to
msg:ByteBuf: the message to encode to an other one
out:List<Object>: the List into which the encoded msg should be added needs to do some kind of aggregation

Annotations

@Override

Exceptions

Exception:: is thrown if an error occurs

public Class LengthFieldPrepender

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail