Attempting to create a AQ$_JMS_MAP_MESSAGE via PL/SQL

Question

I'm attempting to create a AQ$_JMS_MAP_MESSAGE via PL/SQL but can't get it to work.
I'm able to create a AQ$_JMS_MESSAGE and add it to an AQ (of the correct type) however the AQ$_JMS_MAP_MESSAGE can not be constructed in the same way as it does not have a CONSTRUCT method.
Is it possible to create this type of JMS message with PL/SQL? The documentation seems to imply that it can be done.
I have tried the following but get an error; the AQ table is of type SYS.AQ$_JMS_MAP_MESSAGE.
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procedure addMessageToAQ AS
--message   SYS.AQ$_JMS_MAP_MESSAGE;
message SYS.AQ$_JMS_MESSAGE;
eopt dbms_aq.enqueue_options_t;
mprop dbms_aq.message_properties_t;
enq_msgid raw(16);
BEGIN
message := SYS.AQ$_JMS_MESSAGE.CONSTRUCT(DBMS_AQ.JMS_MAP_MESSAGE);
IF ( message.message_type = DBMS_AQ.JMS_MAP_MESSAGE) THEN
DBMS_OUTPUT.PUT_LINE('The message is a map message');
END IF;
message.message_type := DBMS_AQ.JMS_MAP_MESSAGE;
message.header.set_string_property('header1','hvalue1');
message.header.set_string_property('header2','hvalue2');
message.header.set_string_property('header3','hvalue3');
message.set_string_property('content1', 'cvalue1');
message.set_string_property('content2', 'cvalue2');
message.set_string_property('content3', 'cvalue3');
DBMS_AQ.enqueue(queue_name => 'PROCESS_PASSP_APL_Q',
enqueue_options => eopt,
message_properties => mprop,
payload => message,
msgid => enq_msgid);
END;
=====================================================
ORA-25215: user_data type and queue type do not match
ORA-06512: at "SYS.DBMS_AQ", line 204
ORA-06512: at "BDEV1.PS2032_MVMNTHNDSHKEXTRCT", line 48
ORA-06512: at "BDEV1.JDEV_TMP_PROC_1", line 3
The message is a map message
Process exited.

Answer 1

As far as I know every object type in database has an implicit construct . It's just that nobody created some nice constructor. Take this example as a "hard way" to create message:
-- jms_text_message related variables
tmp_text_message SYS.AQ$_JMS_TEXT_MESSAGE;
tmp_header SYS.AQ$_JMS_HEADER;
tmp_array SYS.AQ$_JMS_USERPROPARRAY;
-- AQ related variables
enq_msgid RAW(16);
eopt dbms_aq.enqueue_options_t;
mprop dbms_aq.message_properties_t;
-- get current date time, so it doesn't change during run of procedure
current_datetime := TO_CHAR(SYSDATE,'DDMMYYYYHHMISS');
-- initialize array
tmp_array := SYS.AQ$_JMS_USERPROPARRAY(SYS.AQ$_JMS_USERPROPERTY('EVENT_TYPE', 100, 'PL_SQL', NULL, 27));
-- create header
tmp_header := SYS.AQ$_JMS_HEADER(SYS.AQ$_AGENT(NULL, NULL, 0), NULL, NULL, NULL, NULL, 0, tmp_array);
-- create JMS_TEXT_MESSAGE
tmp_text_message := SYS.AQ$_JMS_TEXT_MESSAGE(tmp_header,4,'AAAA',NULL);
dbms_aq.enqueue(
queue_name => 'job_queue',
enqueue_options => eopt,
message_properties => mprop,
payload => tmp_text_message,
msgid => enq_msgid);
...