MigratoryDataMessage

Represent a message.

Public Classes

Public Functions

Public Functions Documentation

function MigratoryDataMessage

MigratoryDataMessage(
    String subject,
    byte[] content,
    String closure,
    QoS qos,
    boolean retained,
    String reply_subject
)

Create a MigratoryDataMessage object.

Parameters:

• subject The subject of the message
• content The content of the message
• closure The closure of the message (OPTIONAL)
• qos the QoS level of the message; the default is [QoS.GUARANTEED](/docs/client-api/python/classes/interfacemigratorydatamessage_1_1qos/#variable-guaranteed) (OPTIONAL)
• retained indicate whether or not the message should be/was retained by the server; the default is true (OPTIONAL)
• replySubject the reply subject of the message (OPTIONAL)

If a reply subject is attached to a message, the message acts as a request message. The clients which receive a request message will be able to reply by sending back one or more messages having as subject the reply subject.

Note: If the reply subject is not already subscribed, it will be subscribed by the library implicitly, and it can be reused for request/reply interactions (and even for receiving multiple replies to one request). When it is not needed anymore, it should be unsubscribed explicitly.

function get_subject

String get_subject()

Get the subject of the message.

Return: A string representing the subject of the message

function get_content

String get_content()

Get the content of the message.

Return: A string representing the content of the message

function get_closure

String get_closure()

Get the closure of the message.

Return: The closure data of the message

function is_retained

inline boolean is_retained()

Indicate whether or not the message should be/was retained by the server.

Return: true if the message should be, or was, retained by the server

function get_reply_to_subject

String get_reply_to_subject()

Get the subject to be used to reply to this message.

Return: The subject to be used to reply to this message.

A client which receives a message containing a reply subject should interpret the message as a request. It has the option to use the reply subject - extracted from the message with this method - to send a reply.

function get_qos

inline QoS get_qos()

Get the QoS level of the message.

Return: the QoS level of the message

function get_message_type

inline MessageType get_message_type()

Get the MessageType of the message.

Return: the message type of the message

function set_compressed

void set_compressed(
    boolean compressed
)

Set whether to compress the content of the message or not.

Parameters:

• compressed if true, the content of the message will be published in ZLIB-compressed format; if false no compression format will be used; the default value is false.

Note: If compression is enabled with this method but the size of the content of the message is smaller than the size of compressed content, then the message will be sent uncompressed to save bandwidth and CPU cycles with the decompression on the receiver side.

function is_compressed

boolean is_compressed()

Indicate whether or not the message should be/was compressed.

Return: Return whether or not the message should be/was compressed. If the received message was compressed, the library automatically decompresses its content without any additional code.

function set_compressed

void set_compressed(bool compressed)

Sets whether the content of the message should be compressed.

If true, compression is enabled using the default algorithm ZLIB_BASE64, unless compression has already been explicitly enabled via set_compression_algorithm() with ZLIB_BINARY, in which case the existing algorithm – which is more compact – is preserved.

If false, compression is disabled (i.e., compression algorithm is set to NONE).

Note: If compression is enabled but the resulting compressed content is larger than the original, the message will be sent uncompressed to optimize bandwidth and avoid unnecessary decompression on the subscriber side.

Default behavior: If neither this method nor set_compression_algorithm() is called, compression is disabled by default (i.e. the compression algorithm is set to NONE).

Parameters:

• compressed — true to enable compression using ZLIB_BASE64 unless already enabled with ZLIB_BINARY; false to disable.

function set_compression_algorithm

void set_compression_algorithm(CompressionAlgorithm algorithm)

Sets the algorithm that determines whether and how the message is compressed.

Supported algorithms:

• NONE — disables compression
• ZLIB_BASE64 — enables compression with base64 encoding
• ZLIB_BINARY — enables binary compression (most compact)

This method overrides any previously configured compression setting, including one set by set_compressed().

Note: If compression results in a larger payload, the message will be sent uncompressed.

Default behavior: If neither this method nor set_compressed() is called, compression is disabled by default (i.e. the compression algorithm is set to NONE).

Parameters:

• algorithm — the CompressionAlgorithm to apply.

function get_compression_algorithm

CompressionAlgorithm get_compression_algorithm()

Returns the compression algorithm currently set for the message.

The returned value reflects the current compression setting of the message, whether it was set via set_compressed() and/or set_compression_algorithm().

Return: the CompressionAlgorithm set for this message.

function is_compressed

bool is_compressed()

Indicates whether the message should be or was compressed.

On the publisher side, this indicates whether compression should be applied before sending the message. On the subscriber side, this indicates whether the message was received in compressed form. In both cases, if compression is involved, the library automatically handles compression and decompression.

Return: true if compression is enabled on the publisher side or the message was received compressed on the subscriber side; false otherwise.

Enum CompressionAlgorithm

Represents the available compression algorithms for message payloads.

class CompressionAlgorithm {
   const NONE = 0;         // No compression applied
   const ZLIB_BASE64 = 1;  // ZLIB + Base64 encoding
   const ZLIB_BINARY = 2;  // ZLIB + raw binary
}

Enum Values:

• NONE — No compression applied.
• ZLIB_BASE64 — Compression using ZLIB with base64 encoding for UTF-8 transport.
• ZLIB_BINARY — Compression using ZLIB with raw binary output for max efficiency.

Each enum constant is associated with an internal numeric code.