To configure the FixedWidth data handler, take the following steps:
- Enter the appropriate values for the attributes of the FixedWidth child
meta-object.
- Create or modify business object definitions so that they support the data
handler.
Each of these steps is described in more detail in the following
sections.
To configure a FixedWidth data handler, you must ensure that its
configuration information is provided in the FixedWidth child
meta-object. For the FixedWidth data handler, IBM delivers the
MO_DataHandler_DefaultFixedWidthConfig child meta-object. Each
attribute in this meta-object defines a configuration property for the
FixedWidth data handler. Table 55 describes the attributes for this child meta-object.
Table 55. Child meta-object attributes for the FixedWidth data handler
Meta-object attribute name
| Meaning
| Delivered default value
|
ClassName
| Name of the data handler class to load for use with the MIME type that
matches the name of the attribute in the top-level data-handler
meta-object. This attribute has the FixedWidth child meta-object as its
type.
| com.crossworlds. DataHandlers.
text.fixedwidth
|
Alignment
| Adds or removes the
PadCharacter attribute. For event processing, pad characters
are trimmed. For request processing, pad characters are added.
Possible values are BOTH, LEFT, and
RIGHT. For example, "LEFT" alignment means the
value of the business object attributes moves to the extreme left of the space
for that attribute value. "BOTH" alignment for event
notification means that pad characters are trimmed off both the left and right
sides. "RIGHT" alignment for request processing means that
the right side is padded with pad characters.
| BOTH
|
BOCountSize
| Specifies the space allocated for the total number of business objects
being processed.
| 3
|
BONameSize
| Specifies the space allocated for the name of the business object.
| 50
|
BOVerbSize
| Specifies the space allocated for the verb.
| 20
|
CxBlank
| When converting from a business object, the FixedWidth data handler
writes the value configured for the Default Value property of the
CxBlank meta-object attribute to the fixed-width document whenever
it encounters a business object attribute whose value is
CxBlank. When converting to a business object, the
FixedWidth data handler assigns the value configured for the Default Value
property of the CxBlank meta-object attribute to the business
object attribute's value whenever it encounters the value of this
CxBlank meta-object attribute in the fixed-width document.
Business objects must have at least one primary key that does not
contain the value CxBlank at runtime.
| CxBlank value
|
CxIgnore
| When converting from a business object, the FixedWidth data handler
writes the value configured for the Default Value property of the
CxIgnore meta-object attribute to the fixed-width document whenever
it encounters a business object attribute whose value is
CxIgnore. When converting to a business object, the
FixedWidth data handler assigns the value configured for the Default Value
property of the CxIgnore meta-object attribute to the business
object attribute's value whenever it encounters the value of this
CxIgnore meta-object attribute in the fixed-width document.
Business objects must have at least one primary key that does not
contain the value CxIgnore at runtime.
| CxIgnore value
|
DummyKey
| Key attribute required by the business integration system.
| 1
|
OmitObjectEventId
| Boolean value to determine whether or not to include
ObjectEventId data in business-object-to-string and
string-to-business-object conversions.
| false
|
PadCharacter
| Indicates spaces to add or remove for alignment. You can specify
any character as the pad character.
| #
|
Truncation
| Sets removal of characters. If true, any attribute
value in the business object that is greater than MaxLength is
truncated to MaxLength during request processing. If
false, an error is logged and formatting stops.
| false
|
ObjectEventId
| Placeholder not used by the data handler but required by the business
integration system.
| none
|
The "Delivered default value" column in Table 55 lists the value in the Default Value property for the
corresponding attribute in the delivered business object. You must
examine your environment and set the Default Value properties of those
attributes to the appropriate values for your system and your FixedWidth
documents. You must make sure that at least the ClassName
attribute has a default value.
- Note:
- Use Business Object Designer to modify business object definitions.
The FixedWidth data handler makes assumptions about the structure of the
business objects that it handles. Therefore, when you create a business
object for conversion using the FixedWidth data handler, follow these
rules:
- Make sure that every attribute in the business object definition has an
appropriate MaxLength property value. This ensures that the
FixedWidth data handler can properly process the conversion of data from a
business object to a FixedWidth format and from a FixedWidth format to a
business object.
- Make sure that the
ObjectEventId attribute is included in every business object at all
levels of a business object hierarchy. Business Object Designer does
this automatically when it saves a business object definition, but you should
confirm that the requirement is met.
There are no requirements regarding the structure of the business objects
for the FixedWidth data handler. The data handler can process any
business object as long as the
MaxLength attribute property has a value.
The business objects that the data handler processes can have any name
allowed by the business integration system.
Business object architecture contains various properties that apply to
attributes. Table 56 describes how the FixedWidth data handler interprets these
properties and describes how to set the properties when modifying a business
object.
Table 56. Attribute properties for business objects converted using the FixedWidth data handler
Property name
| Description
|
Name
| Each business object attribute must have a unique name.
|
Type
| Each business object attribute must have a type, such as Integer, String,
or the type of a contained child business object.
|
Key
| Not used by the FixedWidth data handler.
|
MaxLength
| Determines the width of the field in which the attribute value is
included.
|
Foreign Key
| Not used by the FixedWidth data handler.
|
Required
| Not used by the FixedWidth data handler.
|
Default Value
| Not used by the FixedWidth data handler.
|
Cardinality
| Supports cardinality 1 and cardinality n objects.
|
The FixedWidth data handler does not require any application-specific
information in business objects or their attributes. The data handler
does, however, check for the existence of the cw_mo_ tag, which a
business object might use to indicate any child meta-object that the connector
uses. The data handler ignores any attribute identified by the
cw_mo_ tag in the application-specific information of the business
object. For more information about the cw_mo_ tag, see Implementing conversion from a business object.
The FixedWidth data handler can convert any business object to a FixedWidth
string as long as the business object delivers data in a form that complies
with the requirements of the data handler. The single requirement of
the FixedWidth data handler is that each business object attribute have a
MaxLength value specified. Existing business objects may
need to be modified to specify an appropriate value for
MaxLength.
Although existing business objects that meet this requirement can be
converted by the FixedWidth data handler, a good practice is to create your
own business objects for each type of data to be processed. If you use
a sample business object, or a business object developed to support the same
application in another implementation, be sure to modify the definition as
necessary to include only the attributes required for the implementation for
which you are developing.
Therefore, to convert existing business objects to a form that closely
corresponds to your data, modify the business object to provide only the data
required by the application and the information required by the data
handler. To adapt existing business objects for use with the FixedWidth
data handler, do the following:
- Perform a functional analysis of the target application, and compare the
results to existing business objects to determine the required fields of a
business object definition.
- Use Business Object Designer to add or delete attributes from the business
object definition as needed.
