Non-Literal Attributes 

You define the non-literal attributes of an ST program using the statement tt:attribute. A non-literal attribute is assigned to an attribute of an XML element of the XML document. During serialization, the content of the non-literal attribute sets the value of the attribute in the XML document; during deserialization, the value of the attribute in the XML document is read and processed.

General Format

General non-literal attributes have the following syntax:

 

<tt:attribute name=″attr″ [ref=″node″]>

  ...

</tt:attribute>

 

You can specify this statement one or more times within a literal XML element before its subelements. Each statement defines a non-literal attribute of the current XML element with the name attr specified in name. The optional attribute ref sets the current node node for the context of the non-literal attribute attr.

Serializing Non-Literal Attributes

During serialization, the name attr of the attribute is written together with =″or =′ into the definition of the current XML element. After that, the content of tt:attribute is serialized and the result is written after attr=″ or attr=′. The result of the serialization must not be structured, which means that it must not contain subelements. Finally, the attribute is completed with ″ or ′.

Note

In a valid XML document, the names of the attributes of an XML element must be unique. For performance reasons, this is not checked during the serialization of non-literal attributes; the application developers themselves are responsible.

Deserializing Non-Literal Attributes

During deserialization, the name of the attribute is compared to the attributes of the current XML element in the source XML document. The sequence of the attributes is of no concern. The deserialization fails if the attribute does not exist in the inbound stream. After that, the value of the attribute is deserialized according to the content of tt:attribute and the closing character is compared. The deserialization fails if not the entire content of the attribute is deserialized. Surplus attributes of the inbound stream are ignored.

 

Special Form of Non-Literal Attributes

A special form of non-literal attributes combines the tt:value command with the above syntax:

 

<tt:attribute name=″attr″ value-ref=″node″
                          [map=″mapping_list″] />

 

This special form is a short form of:

 

<tt:attribute name=″attr″>
  <tt:value ref=″node″ [map=″mapping_list″] />
</tt:attribute>

 

This allows you to easily formulate the frequent situation of expressing an elementary value as the content of an attribute.

 

Example

In the ST program below, the values of the data roots ROOT1and ROOT2 are serialized as values of the attributes attr1 and attr2of elements X or are deserialized from them, respectively.

<tt:transform xmlns:tt="http://www.sap.com/transformation-templates">

  <tt:root name="ROOT1"/>
  <tt:root name="ROOT2"/>

  <tt:template>
    <X>
      <tt:attribute name="attr1" value-ref="ROOT1" />
      <tt:attribute name="attr2" value-ref="ROOT2" />
      <Y>...</Y>
    </X>
  </tt:template>

</tt:transform>

 

If you pass the values "Text1“ and “Text2“ to ROOT1and ROOT2, the result of a serialization is:

 

<X attr1="Text1" attr2="Text2">
  <Y>...</Y>
</X>

 

To deserialize the above result again, you can use the ST program below, even though the sequence of the attributes is different.

 

<tt:transform xmlns:tt="http://www.sap.com/transformation-templates">

  <tt:root name="ROOT1"/>
  <tt:root name="ROOT2"/>

  <tt:template>
    <X>
      <tt:attribute name="attr2" value-ref="ROOT2" />
      <tt:attribute name="attr1" value-ref="ROOT1" />
      <Y>...</Y>
    </X>
  </tt:template>

</tt:transform>