Configuring the FixedWidth data handler

To configure the FixedWidth data handler, take the following steps:

Each of these steps is described in more detail in the following sections.

Configuring the FixedWidth child meta-object

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 54 describes the attributes for this child meta-object.

Table 54. 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 54 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 Express to modify business object definitions.

Business objects requirements

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:

Business object structure

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 attribute properties

Business object architecture contains various properties that apply to attributes. Table 55 describes how the FixedWidth data handler interprets these properties and describes how to set the properties when modifying a business object.

Table 55. 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.

Business object application-specific information

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.

Using existing business object definitions

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:

  1. 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.
  2. Use Business Object Designer Express to add or delete attributes from the business object definition as needed.

Copyright IBM Corp. 2003