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. TODO: make state private

Field Summary

Fields

Modifier and Type	Field and Description
java.io.ByteArrayOutputStream	accumulator Frame payload (for outbound frames) TODO: make final; currently modified explicitly in tests.
int	channel Frame channel number, 0-65535
byte[]	payload Frame payload bytes (for inbound frames)
int	type Frame type code

Constructor Summary

Constructors

Constructor and Description
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

Methods

Modifier and Type	Method and Description
static long	arraySize(java.util.List<?> values) Computes the AMQP wire-protocol length of an encoded field-array
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 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 long	tableSize(java.util.Map<java.lang.String,java.lang.Object> table) Computes the AMQP wire-protocol length of protocol-encoded table entries.
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 final int type

Frame type code

channel

public final int channel

Frame channel number, 0-65535

payload

public final byte[] payload

Frame payload bytes (for inbound frames)

accumulator

public java.io.ByteArrayOutputStream accumulator

Frame payload (for outbound frames) TODO: make final; currently modified explicitly in tests.

Constructor Detail

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 protocol-encoded table entries.

Throws:

java.io.UnsupportedEncodingException

arraySize

public static long arraySize(java.util.List<?> values)
                      throws java.io.UnsupportedEncodingException

Computes the AMQP wire-protocol length of an encoded field-array

Throws:

java.io.UnsupportedEncodingException