Configuring meta-objects

The connector for JMS can recognize and read two kinds of meta-objects:

The attribute values of the dynamic child meta-object duplicate and override those of the static meta-object. For an overview of metadata and static versus dynamic meta-objects, see Metadata and meta-objects.

When deciding upon which meta-object will work best for your implementation, consider the following:

Meta-object properties

Table 10 provides a complete list of properties supported in meta-objects. Refer to these properties when implementing meta-objects.

Not all properties are available in both objects. Nor are all properties are readable from or writable to the message header. See the appropriate sections on event and request processing in Adapter for JMS overview, to determine how a specific property is interpreted and used by the connector.

Table 10. JMS meta-object properties

Property name Definable in static meta-object Definable in dynamic meta-object Description
DataHandlerConfigMO
 
Yes Yes Meta-object passed to data handler to provide configuration information. If specified in the static meta-object, this will override the value specified in the DataHandlerConfigMO connector property. Use this static meta-object property when different data handlers are required for processing different business object types. Use the dynamic child meta-object for request processing when the data format may be dependent on the actual business data. The specified business object must be supported by the connector agent. See the description in Configuring connector-specific properties.
DataHandlerMimeType
 
Yes Yes Allows you to request a data handler based on a particular MIME type. If specified in the static meta-object, this will override the value specified in the DataHandlerMimeType connector property. Use this static meta-object property when different data handlers are required for processing different business object types. Use the dynamic child meta-object for request processing when the data format might be dependent on the actual business data. The business object specified in DataHandlerConfigMO should have an attribute that corresponds to the value of this property. See the description in Configuring connector-specific properties.
DataHandlerClassName
 
Yes Yes See the description in Configuring connector-specific properties.
InputFormat
 
Yes Yes Format or type of inbound (event) messages. This value assists in identifying the content of the message and would be specified by the application that generated the message. The field that the connector considers as defining the format in the message can be user-defined via the connector-specific property MessageFormatProperty.
OutputFormat
 
Yes Yes Format to be populated in outbound messages. If the OutputFormat is not specified, the input format is used, if available.
InputDestination Yes Yes This property is used to match incoming messages to business objects only. By contrast, the InputDestination connector-specific property defines which destinations the adapter polls and is the only property that the adapter uses to determine which destinations to poll. In the MO, the InputDestination property and the InputFormat property can serve as criteria for the adapter to map a given message to a specific business object. To implement this feature, you would use connector-specific properties to configure multiple input destinations and optionally map different data handlers to each one based on the input formats of incoming messages.


Do not set this property using default conversion properties; its value is used

OutputDestination
 
Yes Yes Destination to which the outbound message is written.
ResponseTimeout
 
Yes Yes Indicates the length of time in milliseconds to wait before timing out when waiting for a response in synchronous request processing. The connector returns SUCCESS immediately without waiting for a response if this is left undefined or with a value less than zero.
TimeoutFatal
 
Yes Yes Used in synchronous request processing to trigger the connector to return an error message if a response is not received. If this property is True, the connector returns APPRESPONSETIMEOUT to the broker when a response is not received within the time specified by ResponseTimeout. If this property is undefined or set to False, then on a response timeout the connector fails the request but does not terminate. Default = False.
Below are fields mapping specifically to the JMS message header. For specific explanations, interpretation of values, and more, see the JMS API specification. JMS providers may interpret some fields differently so also check your JMS provider documentation for any deviations.
ReplyToDestination
Yes Destination to which a response message for a request is to be sent.
Type
Yes Type of message. Generally user-definable, depending on JMS provider.
MessageID
Yes Unique ID for message (JMS provider specific).
CorrelationID Yes Yes Used in response messages to indicate the ID of the request message that initiated this response.
Delivery Mode Yes Yes Specifies whether the message is persisted or not in the MOM system. Acceptable values:
1=non-persistent
2=persistent
Other values, depending on the JMS provider, may be available.
Priority
Yes Numeric priority of message. Acceptable values: 0 through 9 inclusive (low to high priority).
Destination
Yes Current or last (if removed) location of message in MOM system.
Expiration
Yes Time-to-live of message. If specified as zero, expiration is set to zero. Zero indicates to the JMS provider that the message does not expire.
Redelivered
Yes Indicates that the JMS provider most likely attempted to deliver the message to the client earlier but receipt was not acknowledged.
Timestamp
Yes Time message was handed off to JMS provider.
UserID
Yes Identity of the user sending the message.
AppID
Yes Identity of the application sending the message.
DeliveryCount
Yes Number of delivery attempts.
GroupID
Yes Identity of the message group.
GroupSeq
Yes Sequence of this message in the message group specified in GroupID.
JMSProperties
Yes See JMS properties.

Configuring a static meta-object

The JMS configuration static meta-object contains a list of conversion properties defined for different business objects. To view a sample static meta-object, launch Business Object Designer and open the following sample that is shipped with the adapter: connectors\JMS\Samples\Sample_JMS_MO_Config.xsd.

The connector supports at most one static meta-object at any given time. You implement a static meta-object by specifying its name for connector property ConfigurationMetaObject

The structure of the static meta-object is such that each attribute represents a single business object and verb combination and all the meta-data associated with processing that object. The name of each attribute should be the name of the business object type and verb separated by an underscore, such as Customer_Create. The attribute application-specific information should consist of one or more semicolon-delimited name-value pairs representing the meta-data properties you want to specify for this unique object-verb combination.

Table 11. Static meta-object structure

Attribute name Application-specific text
<business object type>_<verb>
 
    property=value;property=value;...
 
<business object type>_<verb>
 
    property=value;property=value;...
 

For example, consider the following meta-object:

Table 12. Sample static meta-object structure

Attribute name Application-specific information
Customer_Create
 
    OutputFormat=CUST;OutputDestination=QueueA
 
Customer_Update
 
OutputFormat=CUST;OutputDestination=QueueB
 
Order_Create
 
OutputFormat=ORDER;OutputDestination=QueueC
 

The meta-object in this sample informs the connector that when it receives a request business object of type Customer with verb Create, to convert it to a message with format CUST and then to place it in destination QueueA. If the customer object instead had verb Update, the message would be placed in QueueB. If the object type was Order and had verb Create, the connector would convert and deliver it with format ORDER to QueueC. Any other business object passed to the connector would be treated as unsubscribed.

Optionally, you may name one attribute Default and assign to it one or more properties in the ASI. For all attributes contained in the meta-object, the properties of the default attribute are combined with those of the specific object-verb attributes. This is useful when you have one or more properties to apply universally (regardless of object-verb combination). In the following example, the connector would consider object-verb combinations of Customer_Create and Order_Create as having OutputDestination=QueueA in addition to their individual meta-data properties:

Table 13. Sample static meta-object structure

Attribute name Application-specific information
Default
 
    OutputDestination=QueueA
 
Customer_Update
 
OutputFormat=CUST
 
Order_Create
 
OutputFormat=ORDER
 

See Table 10 in Meta-object propertiesdescribes the properties that you can specify as application-specific information in the static meta-object.

To implement a static meta-object:

  1. Launch Business Object Designer. For further information, see the Business Object Development Guide.
  2. Open the sample meta-object connectors\JMS\Samples\Sample_JMS_MO_Config.xsd. Figure 3 shows a sample static meta-object in Business Object Designer.

    Figure 3. A sample static meta-object

  3. Edit the attributes and ASI to reflect your requirements, referring to Table 10 and then save the meta-object file.
  4. Specify the name of this meta-object file as the value of the connector property ConfigurationMetaObject.

Mapping data handlers to input destinations

You can use the InputDestination property in the application-specific information of the static meta-object to associate a data handler with an input destination. This feature is useful when dealing with multiple trading partners who have different formats and conversion requirements.

To map a data handler to an input destination:

  1. Launch Connector Configurator. For further information, see Appendix B, Connector Configurator.
  2. Use connector-specific properties (see InputDestination) to configure one or more input destination. Multiple destination names must be delimited by a semicolon.
  3. For each input destination, specify the destination (queue manager if you are implementing PTP messaging style) and input destination name as well as data handler class name and mime type in the application-specific information.

For example, the following attribute in a static meta-object associates a data handler with an InputDestination named CompReceipts:

[Attribute]
 Name = Customer_Create
 Type = String
 Cardinality = 1
 MaxLength = 1
 IsKey = false
 IsForeignKey = false
 IsRequired = false
 AppSpecificInfo =
 InputDestination=//queue.manager/CompReceipts;DataHandlerClassName=com.crossworlds.
 DataHandlers.MQ.disposition_notification;DataHandlerMimeType=message/
 disposition_notification
 IsRequiredServerBound = false
 [End]
 

Configuring a dynamic child meta-object

If it is difficult or unfeasible to specify the necessary metadata through a static meta-object, the connector can optionally accept meta-data delivered at run-time for each business object instance.

Dynamic meta-objects allow you to change the meta-data used by the connector to process a business object on a per-request basis during request processing, and to retrieve information about an event message during event processing.

The structure of the dynamic meta-object is such that each attribute represents a single metadata property and value:meta-object property name =meta-object property value

To implement a dynamic meta-object, you add it as a child to your top-level object and include the name-value pair cw_mo_conn=<MO attribute> in your top-level object ASI where <MO attribute> is the name of the attribute in your top-level object representing the dynamic meta-object. For example:

Customer (ASI = cw_mo_conn=MetaData)
   |-- Id
   |-- FirstName
   |-- LastName
   |-- ContactInfo
   |-- MetaData
         |-- OutputFormat = CUST
         |-- OutputDestination = QueueA
 

Upon receipt of a request populated as shown above, the connector would convert the Customer object to a message with format CUST and then put the message in queue QueueA.

Business objects can use the same or different dynamic meta-object or none at all.

Note:
All standard IBM WebSphere data handlers are designed to ignore this dynamic meta-object attribute by recognizing the cw_mo_ tag. You must do the same when developing custom data handlers for use with the adapter.

The connector recognizes and reads conversion properties from a dynamic meta-object that is added as a child to the top-level business object passed to the connector. The attribute values of the dynamic child meta-object duplicate the conversion properties that you can specify via the static meta-object that is used to configure the connector.

Since dynamic child meta object properties override those found in static meta-objects, if you specify a dynamic child meta-object, you need not include a connector property that specifies the static meta-object. Accordingly, you can use a dynamic child meta-object independently of the static meta-object and vice-versa.

See Table 10 in Meta-object propertiesdescribes the properties that you can specify as application-specific information in the dynamic meta-object.

To implement a dynamic meta-object:

  1. Launch Business Object Designer. For further information, see the Business Object Development Guide.
  2. Open the sample meta-object connectors\JMS\Samples\Sample_JMS_DynMO.xsd. Figure 4 shows a sample dynamic meta-object in Business Object Designer.

    Figure 4. A sample dynamic meta-object

  3. Edit the attributes and properties to reflect your requirements for this business object and save it.
  4. Add the dynamic meta-object as a child to your top-level object and include the name-value pair cw_mo_conn=<MO attribute> in your top-level object ASI where <MO attribute> is the name of the attribute in your top-level object representing the dynamic meta-object.

Population of the dynamic child meta-object during polling

In order to provide collaborations with more information regarding messages retrieved during polling, the connector populates specific attributes of the dynamic meta-object, if already defined for the business object created.

Table 14 shows how a dynamic child meta-object might be structured for polling.

Table 14. JMS dynamic child meta-object structure for polling

Attribute name Sample value
InputFormat
 
CUST_IN
 
InputQueue
 
MYInputQueue
 
OutputFormat
 
CxIgnore
 
OutputQueue
 
CxIgnore
 
ResponseTimeout
 
CxIgnore
 
TimeoutFatal
 
CxIgnore
 

As shown in Table 14, you can define additional attributes, Input_Format and Inputdestination, in a dynamic child meta-object. The Input_Format is populated with the format of the message retrieved, while the InputDestination attribute contains the name of the destination from which a given message has been retrieved. If these properties are not defined in the child meta-object, they will not be populated.

Example scenario:

JMS headers and dynamic child meta-object attributes

You can add attributes to a dynamic meta-object to gain more information about, and more control over, the message transport. This section describes these attributes and how they affect event notification and request processing.

JMS properties

Unlike other attributes in the dynamic meta-object, JMSProperties must define a single-cardinality child object. Every attribute in this child object must define a single property to be read/written in the variable portion of the JMS message header as follows:

  1. The name of the attribute has no semantic value.
  2. The type of the attribute should always be String regardless of the JMS property type.
  3. The application-specific information of the attribute must contain two name-value pairs defining the name and format of the JMS message property to which the attribute maps. The name is user-definable. The value type must be one of the following:

The table below shows application-specific information properties that you must define for attributes in the JMSProperties object.

Table 15. Application-specific information for JMS property attributes

Attribute Possible values ASI Comments
Name Any valid JMS property name (valid = compatible with type defined in ASI) name=<JMS property name>;type=<JMS property type> Some vendors reserve certain properties to provide extended functionality. In general, users should not define custom properties that begin with JMS unless they are seeking access to these vendor-specific features.
Type String type=<see comments> This is the type of the JMS property. The JMS API provides a number of methods for setting values in the JMS Message: setIntProperty, setLongProperty, setStringProperty, etc. The type of the JMS property specified here dictates which of these methods is used for setting the property value in the message.

In the example below, a JMSProperties child object is defined for the Customer object to allow access to the user-defined fields of the message header:

Customer (ASI = cw_mo_conn=MetaData)
   |-- Id
   |-- FirstName
   |-- LastName
   |-- ContactInfo
   |-- MetaData
         |-- OutputFormat = CUST
         |-- OutputDestination = QueueA
         |-- JMSProperties
              |-- RoutingCode = 123 (ASI= name=RoutingCode;type=Int)
              |-- Dept = FD (ASI= name=RoutingDept;type=String)
 

To illustrate another example, Figure 5 shows attribute JMSProperties in the dynamic meta-object and definitions for four properties in the JMS message header: ID, GID, RESPONSE and RESPONSE_PERSIST. The application-specific information of the attributes defines the name and type of each. For example, attribute ID maps to JMS property ID of type String).

Figure 5. JMS properties attribute in a dynamic meta-object


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