com.rabbitmq.client.impl
Class Frame

java.lang.Object
  com.rabbitmq.client.impl.Frame

public class Frame
extends java.lang.Object

Represents an AMQP wire-protocol frame, with frame type, channel number, and payload bytes.

Field Summary

java.io.ByteArrayOutputStream	accumulator Frame payload (for outbound frames)
int	channel Frame channel number, 0-65535
byte[]	payload Frame payload bytes (for inbound frames)
int	type Frame type code

Constructor Summary

Frame()
Constructs an uninitialized frame.

Frame(int type, int channel)
Constructs a frame for output with a type and a channel number and a fresh accumulator waiting for payload.

Frame(int type, int channel, byte[] payload)
Constructs a frame for input with a type, a channel number and a payload byte array.

Method Summary

static java.util.Map<java.lang.String,java.lang.Object>	buildTable(java.lang.Object[] keysValues) Utility for constructing a java.util.Map instance from an even-length array containing alternating String keys (on the even elements, starting at zero) and values (on the odd elements, starting at one).
static Frame	fromBodyFragment(int channelNumber, byte[] body, int offset, int length)
java.io.DataInputStream	getInputStream() Public API - retrieves a new DataInputStream streaming over the payload
java.io.DataOutputStream	getOutputStream() Public API - retrieves a fresh DataOutputStream streaming into the accumulator
byte[]	getPayload() Public API - retrieves the frame payload
static int	longStrSize(java.lang.String str) Computes the AMQP wire-protocol length of a protocol-encoded long string.
static void	protocolVersionMismatch(java.io.DataInputStream is) Private API - A protocol version mismatch is detected by checking the three next bytes if a frame type of (int)'A' is read from an input stream.
static Frame	readFrom(java.io.DataInputStream is) Protected API - Factory method to instantiate a Frame by reading an AMQP-wire-protocol frame from the given input stream.
static int	shortStrSize(java.lang.String str) Computes the AMQP wire-protocol length of a protocol-encoded short string.
static long	tableSize(java.util.Map<java.lang.String,java.lang.Object> table) Computes the AMQP wire-protocol length of a protocol-encoded table.
java.lang.String	toString()
void	writeTo(java.io.DataOutputStream os) Public API - writes this Frame to the given DataOutputStream

Methods inherited from class java.lang.Object

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

Field Detail

type

public int type

Frame type code

channel

public int channel

Frame channel number, 0-65535

payload

public byte[] payload

Frame payload bytes (for inbound frames)

accumulator

public java.io.ByteArrayOutputStream accumulator

Frame payload (for outbound frames)

Constructor Detail

Frame

public Frame()

Constructs an uninitialized frame.

Frame

public Frame(int type,
             int channel)

Constructs a frame for output with a type and a channel number and a fresh accumulator waiting for payload.

Frame

public Frame(int type,
             int channel,
             byte[] payload)

Constructs a frame for input with a type, a channel number and a payload byte array.

Method Detail

fromBodyFragment

public static Frame fromBodyFragment(int channelNumber,
                                     byte[] body,
                                     int offset,
                                     int length)
                              throws java.io.IOException

Throws:

java.io.IOException

readFrom

public static Frame readFrom(java.io.DataInputStream is)
                      throws java.io.IOException

Protected API - Factory method to instantiate a Frame by reading an AMQP-wire-protocol frame from the given input stream.

Returns:

a new Frame if we read a frame successfully, otherwise null

Throws:

java.io.IOException

protocolVersionMismatch

public static void protocolVersionMismatch(java.io.DataInputStream is)
                                    throws java.io.IOException

Private API - A protocol version mismatch is detected by checking the three next bytes if a frame type of (int)'A' is read from an input stream. If the next three bytes are 'M', 'Q' and 'P', then it's likely the broker is trying to tell us we are speaking the wrong AMQP protocol version.

Throws:

MalformedFrameException - if an AMQP protocol version mismatch is detected

MalformedFrameException - if a corrupt AMQP protocol identifier is read

java.io.IOException

writeTo

public void writeTo(java.io.DataOutputStream os)
             throws java.io.IOException

Public API - writes this Frame to the given DataOutputStream

Throws:

java.io.IOException

getPayload

public byte[] getPayload()

Public API - retrieves the frame payload

getInputStream

public java.io.DataInputStream getInputStream()

Public API - retrieves a new DataInputStream streaming over the payload

getOutputStream

public java.io.DataOutputStream getOutputStream()

Public API - retrieves a fresh DataOutputStream streaming into the accumulator

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

buildTable

public static java.util.Map<java.lang.String,java.lang.Object> buildTable(java.lang.Object[] keysValues)

Utility for constructing a java.util.Map instance from an even-length array containing alternating String keys (on the even elements, starting at zero) and values (on the odd elements, starting at one).

tableSize

public static long tableSize(java.util.Map<java.lang.String,java.lang.Object> table)
                      throws java.io.UnsupportedEncodingException

Computes the AMQP wire-protocol length of a protocol-encoded table.

Throws:

java.io.UnsupportedEncodingException

longStrSize

public static int longStrSize(java.lang.String str)
                       throws java.io.UnsupportedEncodingException

Computes the AMQP wire-protocol length of a protocol-encoded long string.

Throws:

java.io.UnsupportedEncodingException

shortStrSize

public static int shortStrSize(java.lang.String str)
                        throws java.io.UnsupportedEncodingException

Computes the AMQP wire-protocol length of a protocol-encoded short string.

Throws:

java.io.UnsupportedEncodingException