Literal XML Elements und Attributes 

Literal XML elements are XML elements that are no ST commands or that do not lie within the namespace “http://www.sap.com/transformation-templates“ (namespace prefix tt). Attributes of literal XML elements that do not lie within this namespace are called literal attributes.

During serialization, literal XML elements and their literal attributes are passed to the target XML document unchanged; during deserialization they are compared with the XML source document word by word. Besides the literal attributes, literal XML elements can also contain certain attributes with the namespace prefix tt, that is, ST-specific attributes, to set the current node and to control the behavior during deserialization.

General Literal XML Elements

General literal XML elements have the following syntax:

 

<element [attr] [tt:ref=″node″>]
                [tt:lax=lax_flag]
                [tt:extensible=extensible_flag]>
  ...
</element>

 

Here, element is the name of the element and attr is a set of optional literal attributes of any name. The optional ST-specific attribute tt:ref sets the current node node for the context of the literal element. The optional ST-specific attributes tt:lax tt:extensible only have an effect with deserialization. tt:lax determines whether the element name element may differ during deserialization. tt:extensible specifies whether the element’s content can be extended by unspecified elements.

Serializing Literal XML Elements

During serialization, the element beginning <element [attr]> together with its literal attributes attr is passed to the target XML document, the content of the element is serialized and then the element ending </element> is passed. If there are several literal attributes of the same name, only the last one is passed.

Note

For information on namespaces, see Name spaces.

Deserializing Literal XML Elements

During deserialization, the element beginning is compared to the current position of the source XML document. By default, the source XML document must contain an element with the same name with all literal attributes attr with the same content. The sequence of the literal attributes is of no importance. Superfluous literal attributes of the element in the source document are always ignored. If there are several literal attributes of the same name, only the last one is considered.

After a successful comparison of the element beginning, the element content is deserialized and then the element ending is consumed.

 

Special Form of Literal XML Elements

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

 

<element [attr] tt:value-ref=″node″
                [tt:lax=lax_flag]
                [tt:map=″mapping_list″] />

 

This special form is a short form of:

 

<element [attr] [tt:lax=lax_flag]>
  <tt:value ref=″node″ [map=″mapping_list″] />
</element>

 

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

 

Attribute tt:extension cannot be specified together with tt:value-ref.

 

Example

The following ST program can be used to serialize an elementary data object:

 

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

  <tt:root name="ROOT"/>

  <tt:template>
     <X my_attr="attr">
       <tt:value ref="ROOT" />
     </X>
  </tt:template>

</tt:transform>

 

The result of a serialization is as follows, if “abc“ is the value of the ABAP data object bound to ROOT.

 

<X my_attr="attr">abc</X>

 

Note that literal text that does not contain anything but blank space (blanks and line feeds) is irrelevant in ST programs by default. For this reason, the serialization does not result in:

 

<X my_attr="attr">
  abc
</X>

 

If in examples results of serializations with indents and line feeds are shown, they are usually used for clarification and are not really part of the result.

 

The following ST program can deserialize the result, thereby ignoring the literal attribute my_attr:

 

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

  <tt:root name="ROOT"/>

  <tt:template>
    <X>
      <tt:value ref="ROOT"/>
    </X>
  </tt:template>

</tt:transform>

 

The following ST program shows the short form identical to the program above:

 

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

  <tt:root name="ROOT"/>

  <tt:template>
    <X tt:value-ref="ROOT" />
  </tt:template>

</tt:transform>

 

The following ST program triggers the exception CX_ST_MATCH_ELEMENT, because instead of element Y an element X is passed.

 

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

  <tt:root name="ROOT"/>

  <tt:template>
    <Y>
      <tt:value ref="ROOT"/>
    </Y>
  </tt:template>

</tt:transform>

 

The following ST program triggers the exception CX_ST_MATCH_ATTRIBUTE even though the element names match, because the expected literal attribute my_value does not exist in the source document.

 

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

  <tt:root name="ROOT"/>

  <tt:template>
    <X my_value="value">
      <tt:value ref="ROOT"/>
    </X>
  </tt:template>

</tt:transform>

 

A correct attribute name with an incorrect attribute content triggers exception CX_ST_MATCH_TEXT.