Part 7 — IBM MQ Support¶

7.1 MQ Overview¶

The Heirloom PL/I platform provides IBM MQ messaging support through 18 runtime classes. PL/I programs that use MQI (Message Queue Interface) calls are transpiled to Java code that invokes the Heirloom MQ emulation layer.

7.1.1 MQ Architecture¶

┌────────────────────────────────────────────┐
│            MQ Emulation Layer              │
│                                            │
│  ┌──────────────┐  ┌───────────────────┐  │
│  │ Connection   │  │ Message           │  │
│  │ Management   │  │ Operations        │  │
│  │              │  │                   │  │
│  │ MQCONN       │  │ MQGET             │  │
│  │ MQDISC       │  │ MQPUT             │  │
│  │              │  │ MQPUT1            │  │
│  └──────────────┘  └───────────────────┘  │
│                                            │
│  ┌──────────────┐  ┌───────────────────┐  │
│  │ Queue Mgmt   │  │ Transaction       │  │
│  │              │  │ Control           │  │
│  │ MQOPEN       │  │                   │  │
│  │ MQCLOSE      │  │ MQBEGIN           │  │
│  │ MQINQ        │  │ MQCMIT            │  │
│  └──────────────┘  │ MQBACK            │  │
│                     └───────────────────┘  │
│                                            │
│  ┌────────────────────────────────────┐    │
│  │ MQ Data Structures                │    │
│  │ MQMD  - Message Descriptor        │    │
│  │ MQOD  - Object Descriptor         │    │
│  │ MQGMO - Get Message Options       │    │
│  │ MQPMO - Put Message Options       │    │
│  └────────────────────────────────────┘    │
└────────────────────────────────────────────┘

7.1.2 MQ Support in PL/I Programs¶

PL/I programs use MQI calls through CALL statements to the MQ API functions. The compiler and runtime map these to the Heirloom MQ emulation layer.

7.2 MQ Connection Management¶

7.2.1 MQCONN / MQCONNX¶

Connect to a queue manager.

Parameters: QueueManagerName, ConnectionHandle, CompletionCode, ReasonCode

7.2.2 MQDISC¶

Disconnect from a queue manager.

Parameters: ConnectionHandle, CompletionCode, ReasonCode

7.3 MQ Queue Operations¶

7.3.1 MQOPEN¶

Open a queue or topic for access.

Parameters: ConnectionHandle, ObjectDescriptor (MQOD), OpenOptions, ObjectHandle, CompletionCode, ReasonCode

7.3.2 MQCLOSE¶

Close a queue or topic.

Parameters: ConnectionHandle, ObjectHandle, CloseOptions, CompletionCode, ReasonCode

7.3.3 MQINQ¶

Inquire about queue attributes.

Parameters: ConnectionHandle, ObjectHandle, SelectorCount, Selectors, IntAttrCount, IntAttrs, CharAttrLength, CharAttrs, CompletionCode, ReasonCode

7.4 MQ Message Operations¶

7.4.1 MQGET¶

Get a message from a queue.

Parameters: ConnectionHandle, ObjectHandle, MsgDescriptor (MQMD), GetMsgOptions (MQGMO), BufferLength, Buffer, DataLength, CompletionCode, ReasonCode

7.4.2 MQPUT¶

Put a message to an open queue.

Parameters: ConnectionHandle, ObjectHandle, MsgDescriptor (MQMD), PutMsgOptions (MQPMO), BufferLength, Buffer, CompletionCode, ReasonCode

7.4.3 MQPUT1¶

Put a single message (open, put, close in one call).

Parameters: ConnectionHandle, ObjectDescriptor (MQOD), MsgDescriptor (MQMD), PutMsgOptions (MQPMO), BufferLength, Buffer, CompletionCode, ReasonCode

7.5 MQ Transaction Control¶

7.5.1 MQBEGIN¶

Begin a unit of work.

7.5.2 MQCMIT¶

Commit the current unit of work.

7.5.3 MQBACK¶

Back out (rollback) the current unit of work.

7.6 MQ Data Structures¶

7.6.1 MQMD — Message Descriptor¶

Field	Description
MsgId	Message identifier
CorrelId	Correlation identifier
MsgType	Message type (request, reply, datagram, report)
Persistence	Message persistence
Priority	Message priority
Expiry	Message expiration
Format	Message format name
Encoding	Numeric encoding
CodedCharSetId	Character set identifier (CCSID)
ReplyToQ	Reply-to queue name
ReplyToQMgr	Reply-to queue manager name
PutDate	Date message was put
PutTime	Time message was put
PutApplName	Application name

7.6.2 MQOD — Object Descriptor¶

Field	Description
ObjectType	Type of object (queue, topic, etc.)
ObjectName	Name of the object
ObjectQMgrName	Queue manager name
DynamicQName	Dynamic queue name template
ResolvedQName	Resolved queue name (output)
ResolvedQMgrName	Resolved queue manager name (output)

7.6.3 MQGMO — Get Message Options¶

Field	Description
Options	Get options (MQGMO_WAIT, MQGMO_SYNCPOINT, etc.)
WaitInterval	Wait time in milliseconds
MatchOptions	Matching criteria (MsgId, CorrelId)
Signal1	Signal field

7.6.4 MQPMO — Put Message Options¶

Field	Description
Options	Put options (MQPMO_SYNCPOINT, MQPMO_NEW_MSG_ID, etc.)
ResolvedQName	Resolved queue name (output)
ResolvedQMgrName	Resolved queue manager name (output)

7.7 MQ and PL/I Structure Mapping¶

PL/I GROUP structures mapped to MQ data structures via Group-to-MQ conversion
Automatic byte buffer management via ByteBuilder
EBCDIC/ASCII encoding support
Storage solution integration with @get, @set, @auto annotations