Package org.apache.mina.filter.codec.prefixedstring

Class PrefixedStringDecoder

java.lang.Object

org.apache.mina.filter.codec.ProtocolDecoderAdapter

org.apache.mina.filter.codec.CumulativeProtocolDecoder

org.apache.mina.filter.codec.prefixedstring.PrefixedStringDecoder

All Implemented Interfaces:

ProtocolDecoder

public class PrefixedStringDecoder
extends CumulativeProtocolDecoder

A ProtocolDecoder which decodes a String using a fixed-length length prefix.

Author:

Apache MINA Project

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAX_DATA_LENGTH	The default maximum data length
static int	DEFAULT_PREFIX_LENGTH	The default length for the prefix

Constructor Summary

Constructors

Constructor	Description
PrefixedStringDecoder(Charset charset)	Creates a new PrefixedStringDecoder instance
PrefixedStringDecoder(Charset charset, int prefixLength)	Creates a new PrefixedStringDecoder instance
PrefixedStringDecoder(Charset charset, int prefixLength, int maxDataLength)	Creates a new PrefixedStringDecoder instance

Method Summary

Modifier and Type	Method	Description
protected boolean	doDecode(IoSession session, IoBuffer in, ProtocolDecoderOutput out)	Implement this method to consume the specified cumulative buffer and decode its content into message(s).
int	getMaxDataLength()	Gets the maximum number of bytes allowed for a single String
int	getPrefixLength()	Gets the length of the length prefix (1, 2, or 4)
void	setMaxDataLength(int maxDataLength)	Sets the maximum allowed value specified as data length in the incoming data
void	setPrefixLength(int prefixLength)	Sets the number of bytes used by the length prefix

Methods inherited from class org.apache.mina.filter.codec.CumulativeProtocolDecoder

decode, dispose, setTransportMetadataFragmentation

Methods inherited from class org.apache.mina.filter.codec.ProtocolDecoderAdapter

finishDecode

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_PREFIX_LENGTH

public static final int DEFAULT_PREFIX_LENGTH

The default length for the prefix

See Also:

Constant Field Values

DEFAULT_MAX_DATA_LENGTH

public static final int DEFAULT_MAX_DATA_LENGTH

The default maximum data length

See Also:

Constant Field Values

Constructor Detail

PrefixedStringDecoder

public PrefixedStringDecoder(Charset charset,
                             int prefixLength,
                             int maxDataLength)

Creates a new PrefixedStringDecoder instance

Parameters:

charset - the Charset to use for decoding

prefixLength - the length of the prefix

maxDataLength - maximum number of bytes allowed for a single String

PrefixedStringDecoder

public PrefixedStringDecoder(Charset charset,
                             int prefixLength)

Creates a new PrefixedStringDecoder instance

Parameters:

charset - the Charset to use for decoding

prefixLength - the length of the prefix

PrefixedStringDecoder

public PrefixedStringDecoder(Charset charset)

Creates a new PrefixedStringDecoder instance

Parameters:

charset - the Charset to use for decoding

Method Detail

setPrefixLength

public void setPrefixLength(int prefixLength)

Sets the number of bytes used by the length prefix

Parameters:

prefixLength - the length of the length prefix (1, 2, or 4)

getPrefixLength

public int getPrefixLength()

Gets the length of the length prefix (1, 2, or 4)

Returns:

length of the length prefix

setMaxDataLength

public void setMaxDataLength(int maxDataLength)

Sets the maximum allowed value specified as data length in the incoming data

Useful for preventing an OutOfMemory attack by the peer. The decoder will throw a BufferDataException when data length specified in the incoming data is greater than maxDataLength The default value is DEFAULT_MAX_DATA_LENGTH.

Parameters:

maxDataLength - maximum allowed value specified as data length in the incoming data

getMaxDataLength

public int getMaxDataLength()

Gets the maximum number of bytes allowed for a single String

Returns:

maximum number of bytes allowed for a single String

doDecode

protected boolean doDecode(IoSession session,
                           IoBuffer in,
                           ProtocolDecoderOutput out)
                    throws Exception

Implement this method to consume the specified cumulative buffer and decode its content into message(s).

Specified by:

doDecode in class CumulativeProtocolDecoder

Parameters:

session - The current Session

in - the cumulative buffer

out - The ProtocolDecoderOutput that will receive the decoded message

Returns:

true if and only if there's more to decode in the buffer and you want to have doDecode method invoked again. Return false if remaining data is not enough to decode, then this method will be invoked again when more data is cumulated.

Throws:

Exception - if cannot decode in.