Chapter 12. Interoperability

12.1. Interoperating with other AMQP clients

AMQP messages are composed using the AMQP type system. This common format is one of the reasons AMQP clients in different languages are able to interoperate with each other.

When sending messages, Red Hat build of Rhea automatically converts language-native types to AMQP-encoded data. When receiving messages, the reverse conversion takes place.

Note

More information about AMQP types is available at the interactive type reference maintained by the Apache Qpid project.

Table 12.1. AMQP types
AMQP type	Description
`null`	An empty value
`boolean`	A true or false value
`char`	A single Unicode character
`string`	A sequence of Unicode characters
`binary`	A sequence of bytes
`byte`	A signed 8-bit integer
`short`	A signed 16-bit integer
`int`	A signed 32-bit integer
`long`	A signed 64-bit integer
`ubyte`	An unsigned 8-bit integer
`ushort`	An unsigned 16-bit integer
`uint`	An unsigned 32-bit integer
`ulong`	An unsigned 64-bit integer
`float`	A 32-bit floating point number
`double`	A 64-bit floating point number
`array`	A sequence of values of a single type
`list`	A sequence of values of variable type
`map`	A mapping from distinct keys to values
`uuid`	A universally unique identifier
`symbol`	A 7-bit ASCII string from a constrained domain
`timestamp`	An absolute point in time

JavaScript has fewer native types than AMQP can encode. To send messages containing specific AMQP types, use the wrap_ functions from the rhea/types.js module.

Table 12.2. Rhea types before encoding and after decoding
AMQP type	Rhea type before encoding	Rhea type after decoding
`null`	`null`	`null`
`boolean`	`boolean`	`boolean`
`char`	`wrap_char(number)`	`number`
`string`	`string`	`string`
`binary`	`wrap_binary(string)`	`string`
`byte`	`wrap_byte(number)`	`number`
`short`	`wrap_short(number)`	`number`
`int`	`wrap_int(number)`	`number`
`long`	`wrap_long(number)`	`number`
`ubyte`	`wrap_ubyte(number)`	`number`
`ushort`	`wrap_ushort(number)`	`number`
`uint`	`wrap_uint(number)`	`number`
`ulong`	`wrap_ulong(number)`	`number`
`float`	`wrap_float(number)`	`number`
`double`	`wrap_double(number)`	`number`
`array`	`wrap_array(Array, code)`	`Array`
`list`	`wrap_list(Array)`	`Array`
`map`	`wrap_map(object)`	`object`
`uuid`	`wrap_uuid(number)`	`number`
`symbol`	`wrap_symbol(string)`	`string`
`timestamp`	`wrap_timestamp(number)`	`number`

Table 12.3. Rhea and other AMQ client types (1 of 2)
Rhea type before encoding	AMQ C++ type	Red Hat build of Apache Qpid Proton DotNet type
`null`	`nullptr`	`null`
`boolean`	`bool`	`System.Boolean`
`wrap_char(number)`	`wchar_t`	`System.Char`
`string`	`std::string`	`System.String`
`wrap_binary(string)`	`proton::binary`	`System.Byte[]`
`wrap_byte(number)`	`int8_t`	`System.SByte`
`wrap_short(number)`	`int16_t`	`System.Int16`
`wrap_int(number)`	`int32_t`	`System.Int32`
`wrap_long(number)`	`int64_t`	`System.Int64`
`wrap_ubyte(number)`	`uint8_t`	`System.Byte`
`wrap_ushort(number)`	`uint16_t`	`System.UInt16`
`wrap_uint(number)`	`uint32_t`	`System.UInt32`
`wrap_ulong(number)`	`uint64_t`	`System.UInt64`
`wrap_float(number)`	`float`	`System.Single`
`wrap_double(number)`	`double`	`System.Double`
`wrap_array(Array, code)`	-	-
`wrap_list(Array)`	`std::vector`	`Amqp.List`
`wrap_map(object)`	`std::map`	`Amqp.Map`
`wrap_uuid(number)`	`proton::uuid`	`System.Guid`
`wrap_symbol(string)`	`proton::symbol`	`Amqp.Symbol`
`wrap_timestamp(number)`	`proton::timestamp`	`System.DateTime`

Table 12.4. Rhea and other AMQ client types (2 of 2)
Rhea type before encoding	Red Hat build of Apache Qpid Proton Python type
`null`	`None`
`boolean`	`bool`
`string`	`unicode`
`wrap_char(number)`	`unicode`
`wrap_binary(string)`	`bytes`
`wrap_byte(number)`	`int`
`wrap_short(number)`	`int`
`wrap_int(number)`	`long`
`wrap_long(number)`	`long`
`wrap_ubyte(number)`	`long`
`wrap_ushort(number)`	`long`
`wrap_uint(number)`	`long`
`wrap_ulong(number)`	`long`
`wrap_float(number)`	`float`
`wrap_double(number)`	`float`
`wrap_array(Array, code)`	`proton.Array`
`wrap_list(Array)`	`list`
`wrap_map(object)`	`dict`
`wrap_uuid(number)`	-
`wrap_symbol(string)`	`str`
`wrap_timestamp(number)`	`long`

12.2. Interoperating with Red Hat build of Apache Qpid JMS

AMQP defines a standard mapping to the JMS messaging model. This section discusses the various aspects of that mapping. For more information, see the Red Hat build of Apache Qpid JMS Interoperability chapter.

JMS message types

Red Hat build of Rhea provides a single message type whose body type can vary. By contrast, the JMS API uses different message types to represent different kinds of data. The table below indicates how particular body types map to JMS message types.

For more explicit control of the resulting JMS message type, you can set the x-opt-jms-msg-type message annotation. See the Red Hat build of Apache Qpid JMS Interoperability chapter for more information.

Table 12.5. Rhea and JMS message types
Rhea body type	JMS message type
`string`	`TextMessage`
`null`	`TextMessage`
`wrap_binary(string)`	`BytesMessage`
Any other type	`ObjectMessage`

12.3. Connecting to AMQ Broker

AMQ Broker is designed to interoperate with AMQP 1.0 clients. Check the following to ensure the broker is configured for AMQP messaging:

Port 5672 in the network firewall is open.
The AMQ Broker AMQP acceptor is enabled. See Default acceptor settings.
The necessary addresses are configured on the broker. See Addresses, Queues, and Topics.
The broker is configured to permit access from your client, and the client is configured to send the required credentials. See Broker Security.

12.1. Interoperating with other AMQP clients

12.2. Interoperating with Red Hat build of Apache Qpid JMS

JMS message types

12.3. Connecting to AMQ Broker

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