Workflow Queue APIs (Oracle Workflow Help)


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Workflow Queue APIs

Oracle Workflow queue APIs can be called by an application program or a workflow function in the runtime phase to handle workflow Advanced Queues processing. In Oracle Workflow, an 'outbound' and an 'inbound' queue are established. A package of data on the queue is referred to as an event or a message. A message in this context is different from the messages associated with notification activities. Events are enqueued in the outbound queue for agents to consume and process. These agents may be any application that is external to the database. Similarly an agent may enqueue some message to the inbound queue for the Workflow Engine to consume and process. The outbound and inbound queues facilitate the integration of external activities into your workflow processes.

Note: Background engines use a separate 'deferred' queue.

All Oracle Workflow queue APIs are defined in a PL/SQL package called WF_QUEUE. You must execute these queue APIs from the same Oracle Workflow account since the APIs are account dependent.

Attention: In using these APIs, we assume that you have prior knowledge of Oracle8 Advanced Queues concepts and terminology. Refer to the Oracle8 Server Application Developer's Guide for more information on Advanced Queues.

Queue APIs

EnqueueInbound

DequeueOutbound

DequeueEventDetail

PurgeEvent

PurgeItemtype

ProcessInboundQueue

GetMessageHandle

Deferred_queue

Inbound_queue

Outbound_queue

Developer APIs for the Inbound Queue The following APIs are for developers who wish to write to the inbound queue by creating messages in the internal stack rather than using WF_QUEUE.EnqueueInbound( ). The internal stack is purely a storage area and you must eventually write each message that you create on the stack to the inbound queue.

Note: For efficient performance, you should periodically write to the inbound queue to prevent the stack from growing too large.

ClearMsgStack

CreateMsg

WriteMsg

SetMsgAttr

SetMsgResult

Payload Structure

All Oracle Workflow queues use the data type system.wf_payload_t to define the payload for any given message. The payload contains all the information that is required about the event. A description of system.wf_payload_t is as follows:

System.wf_payload_t

Column Name Type Description

ITEMTYPE Varchar2(8) The item type of the event.

ITEMKEY Varchar2(240) The item key of the event.

ACTID Number The function activity instance ID.

FUNCTION_NAME Varchar2(200) The name of the function to execute.

PARAM_LIST Varchar2(4000) A list of "value_name=value" pairs. In the inbound scenario, the pairs are passed as item attributes and item attribute values. In the outbound scenario, the pairs are passed as all the attributes and attribute values of the function (activity attributes).

RESULT Varchar2(30) An optional activity completion result. Possible values are determined by the function activity's Result Type or can be an engine standard result.

Table 1 - 16. (Page 1 of 1)

Column Name	Type	Description

ITEMTYPE	Varchar2(8)	The item type of the event.
ITEMKEY	Varchar2(240)	The item key of the event.
ACTID	Number	The function activity instance ID.
FUNCTION_NAME	Varchar2(200)	The name of the function to execute.
PARAM_LIST	Varchar2(4000)	A list of "value_name=value" pairs. In the inbound scenario, the pairs are passed as item attributes and item attribute values. In the outbound scenario, the pairs are passed as all the attributes and attribute values of the function (activity attributes).
RESULT	Varchar2(30)	An optional activity completion result. Possible values are determined by the function activity's Result Type or can be an engine standard result.
Table 1 - 16. (Page 1 of 1)

Workflow Queue APIs

Payload Structure

See Also