Oracle Workflow Developer's Guide Release 2.6.3.5 Part Number B12161-02 |
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You should define each agent that you will use to communicate events in the Event Manager. Each agent's name must be unique within its system. The agent can be referenced in code within Oracle Workflow by a compound name in the following format:
<agent_name>@<system_name>
For example, the agent WF_IN within the system HUB could be referenced as WF_IN@HUB.
After defining the agents on your local system, you should set them up for event message communication by scheduling agent listeners for local inbound agents and propagation for local outbound agents. You can use Oracle Enterprise Manager to schedule propagation and the Workflow Manager component of Oracle Applications Manager to run agent listeners. In Oracle Workflow Manager you can also view the distribution of event messages on different agents, drill down to view details about individual event messages, and review queue details for the agents. For more information, please refer to the Oracle Applications Manager online help, Oracle Enterprise Manager online help, Oracle Enterprise Manager Support, Oracle Application Developer's Guide - Advanced Queuing or Oracle Streams Advanced Queuing User's Guide and Reference, Distributed Management, Oracle Enterprise Manager Administrator's Guide, and Setting Up the Business Event System, Oracle Workflow Administrator's Guide.
You can run a diagnostic test through Oracle Diagnostics to verify the status of your agents. See: Oracle Workflow Diagnostic Tests, Oracle Workflow Administrator's Guide.
A protocol can represent a network standard, such as SQLNET. It can also represent a business-to-business standard that defines the higher-level message format and handshaking agreements between systems in addition to the network standard.
The Business Event System interacts with an agent through an AQ queue. You can use AQ to perform the propagation of messages by the SQLNET protocol which it supports. In Oracle9i Database and higher, AQ also includes Internet access functionality that lets you perform AQ operations over the Internet by using AQ's Internet Data Access Presentation (IDAP) for messages and transmitting the messages over the Internet using transport protocols such as HTTP or HTTPS. Additionally, the Messaging Gateway feature of AQ in Oracle9i Database and higher enables communication between applications based on non-Oracle messaging systems and AQ, letting you integrate with third party messaging solutions. You can also implement other services to propagate messages by different protocols.
To implement a custom protocol, you must perform the following steps:
<schema>.<queue>@<database link>
In this format, <schema> represents the schema that owns the queue, <queue> represents the queue name, and <database link> represents the name of the database link to the instance where the queue is located.
Note: You must enter the database link name exactly as the name was specified when the database link was created. For example, if a database link is named ORA10.US.ORACLE.COM, you must enter that complete name in the address of an agent on that database. You cannot abbreviate the name to ORA10.
The names of the database links that you want to use for the Business Event System should be fully qualified with the domain names. To confirm the names of your database links, use the following syntax:
SELECT db_link FROM all_db_links
See: Creating Database Links, Oracle Workflow Administrator's Guide.
Event messages within the Oracle Workflow Business Event System are encoded in a standard format defined by the datatype WF_EVENT_T, or, in Java, the BusinessEvent object. You should assign each agent a PL/SQL or Java package called a queue handler that translates between the standard Workflow format and the format required by the agent's queue. Define only one queue handler for an agent, either PL/SQL or Java. See: Event Message Structure, Oracle Workflow API Reference.
Note: Even if the agent's queue uses WF_EVENT_T as its payload type, a queue handler is still required in order to set native AQ message properties.
Oracle Workflow provides two standard queue handlers, called WF_EVENT_QH and WF_ERROR_QH, for queues that use SQLNET propagation and use the WF_EVENT_T datatype as their payload type. You can use WF_EVENT_QH with queues that handle normal Business Event System processing, while WF_ERROR_QH should be used exclusively with error queues.
Oracle Workflow also provides a standard queue handler called WF_EVENT_OJMSTEXT_QH for queues that use the SYS.AQ$_JMS_TEXT_MESSAGE datatype as their payload type. This queue handler enables communication of JMS Text messages through the Business Event System. See: Mapping Between WF_EVENT_T and SYS.AQ$_JMS_TEXT_MESSAGEE, Oracle Workflow API Reference.
If you want to use queues that require a different format, create a custom queue handler for that format. Your custom queue handler must include a set of standard APIs to enqueue and dequeue messages in the custom format. See: Standard APIs for a Queue Handler.
Agent groups can only be used for inbound communication. All agent groups have a direction of In, and only individual agents with a direction of In can be members of an agent group.
You must associate each agent group with a system to which it belongs. However, you can include agents on other systems within the group.
Ensure that you run an agent listener for each agent within the group to receive inbound messages.
Note: You cannot run an agent listener for an agent group. Agent listeners can be run only for individual agents.
You can enable or disable the WF_IN, WF_JMS_IN, WF_WS_JMS_IN, WF_OUT, WF_JMS_OUT, and WF_WS_JMS_OUT agents, but you must not make any other changes to their definitions. You must not make any changes to the definitions of the other agents.
Oracle Workflow automatically runs PL/SQL agent listeners for the standard WF_DEFERRED, WF_ERROR, and WF_NOTIFICATION_IN agents in order to perform deferred subscription processing, error handling for the Business Event System, and inbound e-mail processing for notification mailers, respectively. Oracle Workflow also automatically runs Java agent listeners for the standard WF_JAVA_DEFERRED and WF_JAVA_ERROR agents in order to perform deferred subscription processing and error handling in the middle tier. Additionally, Oracle Workflow provides a Java agent listener named Web Services IN Agent that you can optionally start for the WF_WS_JMS_IN agent. If you want to use the WF_IN and WF_JMS_IN agents for event message propagation, schedule listeners for those agents as well.
Likewise, if you want to use the WF_OUT and WF_JMS_OUT agents for event message propagation, schedule propagation for those agents. You do not need to schedule propagation for the WF_CONTROL, WF_NOTIFICATION_OUT, or WF_WS_JMS_OUT agents, however. The middle tier processes that use WF_CONTROL dequeue messages directly from its queue, and notification mailers send messages placed on the WF_NOTIFICATION_OUT queue. For WF_WS_JMS_OUT, you can optionally start a Web services outbound component named Web Services OUT Agent, provided by Oracle Workflow. For more information, please refer to the Oracle Applications Manager online help, Oracle Enterprise Manager online help, Oracle Enterprise Manager Support, Oracle Application Developer's Guide - Advanced Queuing or Oracle Streams Advanced Queuing User's Guide and Reference, Distributed Management, Oracle Enterprise Manager Administrator's Guide, and Setting Up the Business Event System, Oracle Workflow Administrator's Guide.
You can run a diagnostic test through Oracle Diagnostics to verify that the WF_DEFERRED queue and the WF_ERROR each have only one subscriber rule defined. No custom subscribers should be added to these queues. See: Oracle Workflow Diagnostic Tests, Oracle Workflow Administrator's Guide.
Note: Oracle Workflow also includes three additional agents named WF_REPLAY_IN, WF_REPLAY_OUT, and WF_SMTP_O_1_QUEUE, which are not currently used.
The following table lists the default properties for the standard WF_CONTROL agent. See: Cleaning Up the Workflow Control Queue, Oracle Workflow Administrator's Guide.
Agent Property | Value |
---|---|
Name | WF_CONTROL |
Display Name | Workflow Control Out Queue |
Description | Workflow JMS Text Message Queue used to signal messages to middle tier processes |
Protocol | SQLNET |
Address | <workflow schema>.WF_CONTROL@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_CONTROL |
Direction | Out |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_DEFERRED |
Display Name | WF_DEFERRED |
Description | WF_DEFERRED |
Protocol | SQLNET |
Address | <workflow schema>.WF_DEFERRED@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_QH |
Queue Name | <workflow schema>.WF_DEFERRED |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_ERROR |
Display Name | WF_ERROR |
Description | WF_ERROR |
Protocol | SQLNET |
Address | <workflow schema>.WF_ERROR@<local database> |
System | <local system> |
Queue Handler | WF_ERROR_QH |
Queue Name | <workflow schema>.WF_ERROR |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_JAVA_DEFERRED |
Display Name | Workflow Java Deferred In Queue |
Description | Workflow Java Deferred In Queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_JAVA_DEFERRED@ <local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_JAVA_DEFERRED |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_JAVA_ERROR |
Display Name | Workflow Java Error In Queue |
Description | Workflow Java Error In Queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_JAVA_ERROR@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_JAVA_ERROR |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_IN |
Display Name | WF_IN |
Description | WF_IN |
Protocol | SQLNET |
Address | <workflow schema>.WF_IN@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_QH |
Queue Name | <workflow schema>.WF_IN |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_JMS_IN |
Display Name | Workflow JMS In Queue |
Description | Workflow JMS Text Message Queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_JMS_IN@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_JMS_IN |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_JMS_OUT |
Display Name | Workflow JMS Out Queue |
Description | Workflow JMS Text Message Queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_JMS_OUT@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_JMS_OUT |
Direction | Out |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_NOTIFICATION_IN |
Display Name | Workflow Notification In Queue |
Description | Workflow inbound notification response queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_NOTIFICATION_IN@ <local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_NOTIFICATION_IN |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_NOTIFICATION_OUT |
Display Name | Workflow Notification Out Queue |
Description | Workflow notification outbound queue |
Protocol | SQLNET |
Address | <workflow schema>.WF_NOTIFICATION_OUT@ <local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_NOTIFICATION_OUT |
Direction | Out |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_OUT |
Display Name | WF_OUT |
Description | WF_OUT |
Protocol | SQLNET |
Address | <workflow schema>.WF_OUT@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_QH |
Queue Name | <workflow schema>.WF_OUT |
Direction | Out |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_WS_JMS_IN |
Display Name | WebServices JMS In Queue |
Description | WebServices JMS Text Message Queue for Inbound |
Protocol | SOAP |
Address | <workflow schema>.WF_WS_JMS_IN@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_WS_JMS_IN |
Direction | In |
Status | Enabled |
Agent Property | Value |
---|---|
Name | WF_WS_JMS_OUT |
Display Name | WebServices JMS Out Queue |
Description | WebServices JMS Text Message Queue for Outbound |
Protocol | SOAP |
Address | <workflow schema>.WF_WS_JMS_OUT@<local database> |
System | <local system> |
Queue Handler | WF_EVENT_OJMSTEXT_QH |
Queue Name | <workflow schema>.WF_WS_JMS_OUT |
Direction | Out |
Status | Enabled |
For communication between two systems that both have Oracle Workflow installed, Oracle Workflow provides an external system registration procedure that you can use to automatically copy the inbound agent definitions for the other system into the Event Manager of your local system. See: Registering External Systems.
If your local Workflow-enabled system will communicate with a non-Workflow system, the non-Workflow system must provide its own external propagation agents to handle Business Event System event messages.
To Create or Update an Agent Group
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