org.jboss.netty.handler.codec.frame

类 LengthFieldPrepender

java.lang.Object

org.jboss.netty.handler.codec.oneone.OneToOneEncoder

org.jboss.netty.handler.codec.frame.LengthFieldPrepender

所有已实现的接口:

ChannelDownstreamHandler, ChannelHandler

@ChannelHandler.Sharable
public class LengthFieldPrepender
extends OneToOneEncoder

An encoder that prepends the length of the message. The length value is prepended as a binary form. It is encoded in either big endian or little endian depending on the default ByteOrder of the current ChannelBufferFactory.

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 org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

构造器概要

构造器

构造器和说明
LengthFieldPrepender(int lengthFieldLength) Creates a new instance.
LengthFieldPrepender(int lengthFieldLength, boolean lengthIncludesLengthFieldLength) Creates a new instance.

方法概要

方法

限定符和类型	方法和说明
protected java.lang.Object	encode(ChannelHandlerContext ctx, Channel channel, java.lang.Object msg) Transforms the specified message into another message and return the transformed message.

从类继承的方法 org.jboss.netty.handler.codec.oneone.OneToOneEncoder

doEncode, handleDownstream

从类继承的方法 java.lang.Object

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

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

方法详细资料

encode

protected java.lang.Object encode(ChannelHandlerContext ctx,
                      Channel channel,
                      java.lang.Object msg)
                           throws java.lang.Exception

从类复制的说明: OneToOneEncoder

Transforms the specified message into another message and return the transformed message. Note that you can not return null, unlike you can in OneToOneDecoder.decode(ChannelHandlerContext, Channel, Object); you must return something, at least ChannelBuffers.EMPTY_BUFFER.

指定者:

encode 在类中 OneToOneEncoder

抛出:

java.lang.Exception