io.netty.handler.codec

类 LengthFieldPrepender

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelOutboundHandlerAdapter

io.netty.handler.codec.MessageToByteEncoder<ByteBuf>

io.netty.handler.codec.LengthFieldPrepender

所有已实现的接口:

ChannelHandler, ChannelOutboundHandler

@ChannelHandler.Sharable
public class LengthFieldPrepender
extends MessageToByteEncoder<ByteBuf>

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" |
 +--------+----------------+
 

嵌套类概要

从接口继承的嵌套类/接口 io.netty.channel.ChannelHandler

ChannelHandler.Sharable

构造器概要

构造器

构造器和说明
LengthFieldPrepender(java.nio.ByteOrder byteOrder, int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength) Creates a new instance.
LengthFieldPrepender(int lengthFieldLength) Creates a new instance.
LengthFieldPrepender(int lengthFieldLength, boolean lengthIncludesLengthFieldLength) Creates a new instance.
LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment) Creates a new instance.
LengthFieldPrepender(int lengthFieldLength, int lengthAdjustment, boolean lengthIncludesLengthFieldLength) Creates a new instance.

方法概要

方法

限定符和类型	方法和说明
protected ByteBuf	allocateBuffer(ChannelHandlerContext ctx, ByteBuf msg, boolean preferDirect) Allocate a ByteBuf which will be used as argument of #encode(ChannelHandlerContext, I, ByteBuf).
protected void	encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) Encode a message into a ByteBuf.

从类继承的方法 io.netty.handler.codec.MessageToByteEncoder

acceptOutboundMessage, write

从类继承的方法 io.netty.channel.ChannelOutboundHandlerAdapter

bind, close, connect, deregister, disconnect, flush, read

从类继承的方法 io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, exceptionCaught, handlerAdded, handlerRemoved, isSharable

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从接口继承的方法 io.netty.channel.ChannelHandler

exceptionCaught, handlerAdded, handlerRemoved

构造器详细资料

LengthFieldPrepender

public LengthFieldPrepender(int lengthFieldLength)

Creates a new instance.

参数:

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

抛出:

java.lang.IllegalArgumentException - if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender

public LengthFieldPrepender(int lengthFieldLength,
                    boolean lengthIncludesLengthFieldLength)

Creates a new instance.

参数:

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

lengthIncludesLengthFieldLength - if true, the length of the prepended length field is added to the value of the prepended length field.

抛出:

java.lang.IllegalArgumentException - if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender

public LengthFieldPrepender(int lengthFieldLength,
                    int lengthAdjustment)

Creates a new instance.

参数:

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

lengthAdjustment - the compensation value to add to the value of the length field

抛出:

java.lang.IllegalArgumentException - if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender

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

Creates a new instance.

参数:

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

lengthAdjustment - the compensation value to add to the value of the length field

lengthIncludesLengthFieldLength - if true, the length of the prepended length field is added to the value of the prepended length field.

抛出:

java.lang.IllegalArgumentException - if lengthFieldLength is not 1, 2, 3, 4, or 8

LengthFieldPrepender

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

Creates a new instance.

参数:

byteOrder - the ByteOrder of the length field

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

lengthAdjustment - the compensation value to add to the value of the length field

lengthIncludesLengthFieldLength - if true, the length of the prepended length field is added to the value of the prepended length field.

抛出:

java.lang.IllegalArgumentException - if lengthFieldLength is not 1, 2, 3, 4, or 8

方法详细资料

encode

protected void encode(ChannelHandlerContext ctx,
          ByteBuf msg,
          ByteBuf out)
               throws java.lang.Exception

从类复制的说明: MessageToByteEncoder

Encode a message into a ByteBuf. This method will be called for each written message that can be handled by this encoder.

指定者:

encode 在类中 MessageToByteEncoder<ByteBuf>

参数:

ctx - the ChannelHandlerContext which this MessageToByteEncoder belongs to

msg - the message to encode

out - the ByteBuf into which the encoded message will be written

抛出:

java.lang.Exception - is thrown if an error occurs

allocateBuffer

protected ByteBuf allocateBuffer(ChannelHandlerContext ctx,
                     ByteBuf msg,
                     boolean preferDirect)
                          throws java.lang.Exception

从类复制的说明: MessageToByteEncoder

Allocate a ByteBuf which will be used as argument of #encode(ChannelHandlerContext, I, ByteBuf). Sub-classes may override this method to return ByteBuf with a perfect matching initialCapacity.

覆盖:

allocateBuffer 在类中 MessageToByteEncoder<ByteBuf>

抛出:

java.lang.Exception