SAP ST TT GROUP documentation, setup help and usage info

ARTICLE

ST - tt:group , Grouping

Syntax
<(><<)>tt:group>
<(><<)>tt:[s-|d-]cond [frq="..."] ...
<(><<)>tt:[s-|d-]cond [frq="..."] ...
...
/tt:group

Effect
During deserialization, you can react to variable XML inbound streams containing groups of related elements in any sequence by using the statement tt:group . Hereby, a list of cases is specified in tt:group , where each case is syntactically formulated by a conditional transformation, that is, a subelement
tt:[s-|d-]cond . In this case, tt:[s-]cond defines a serialization-relevant case, and tt:[d-]cond a deserialization-relevant case. Other direct subelements are not possible in tt:group . The statement tt:group can be a subelement of
tt:[s-|d-]cond .
In contrast to conditional transformations positioned outside of
tt:group , there is no need to specify at least one attribute using , data or check for a case, provided that the content of tt:[s-|d-]cond is not a pattern .
In the list of cases, you must note the following:

You may specify any number of serialization-relevant cases, in which no attribute using , data , or check is specified.

You may specify only one deserialization-relevant case that does not contain a pattern . This case is called standard deserialization.

To control how often a deserialization-relevant case must or can be executed during deserialization, tt:[d-]cond within tt:group
can contain the additional attribute frq (frequency) with one of three allowed values:

/tt:[d-]cond ... frq="1"

Required case. The case must be executed exactly once while the group is processed.

/tt:[d-]cond ... frq="?"

Optional case. The case is executed up to once while the group is processed.

/tt:[d-]cond ... frq="*"

Multiple case. The case can be executed any number of times while the group is processed.
For frq="?" and frq="*" , the expected element must not necessarily exist in the XML inbound stream.
Implicit frequency: If the attribute frq is not specified explicitly,

frq="1" is used implicitly in tt:cond cases that do not contain data conditions (that must be executed during serialization).

frq="?" is used implicitly in tt:cond cases that contain a data condition (that need not be executed during serialization).

Serialization
During serialization, the element tt:group is executed once as follows: All serialization-relevant cases with fulfilled prerequisite or no prerequisite using , data , or check are executed in the given order.

Deserialization
During deserialization, the element tt:group initiates a loop. The system tries to select every required case (frequency 1 ) once. As soon as this happens, the loop ends. Until then, optional cases (frequency ? , up to once) and multiple cases (frequency * , also multiple) can also be selected. In every loop pass, one of the deserialization-relevant cases whose maximum case frequency has not yet been reached is selected as follows:
The first case that contains a suitable pattern is executed (deserialization and assertions met).
If no such case exists, the system tries to execute the standard deserialization, if it exists. If the possible prerequisites using
, data , or check of the standard deserialization are not fulfilled, the exception CX_ST_REF_ACCESS occurs.
If no standard deserialization exists, the exception
CX_ST_GROUP_MISSING_CASE occurs.

Example
The following transformation shows how groupings work:
<(><<)>tt:transform
xmlns:tt="http://www.sap.com/transformation-templates">
tt:root name="ROOT1"/
tt:root name="ROOT2"/
tt:root name="ROOT3"/
tt:root name="ROOT4"/
<(><<)>tt:template>
<(><<)>X0>
<(><<)>tt:group>
<(><<)>tt:cond>
<(><<)>X3>
tt:value ref="ROOT3"/
<(><<)>/X3>
<(><<)>/tt:cond>
<(><<)>tt:cond frq="?">
<(><<)>X2>
tt:value ref="ROOT2"/
<(><<)>/X2>
<(><<)>/tt:cond>
<(><<)>tt:cond frq="*">
<(><<)>X1>
tt:value ref="ROOT1"/
<(><<)>/X1>
<(><<)>/tt:cond>
<(><<)>tt:cond>
tt:skip count="1"/
<(><<)>/tt:cond>
<(><<)>/tt:group>
<(><<)>X4>
tt:value ref="ROOT4"/
<(><<)>/X4>
<(><<)>/X0>
<(><<)>/tt:template>
/tt:transform
Assume that an XML inbound stream has the following form:
<(><<)>X0>
<(><<)>X1>1<(><<)>/X1>
<(><<)>X1>2<(><<)>/X1>
<(><<)>X2>3<(><<)>/X2>
<(><<)>X2>4<(><<)>/X2>
<(><<)>X3>5<(><<)>/X3>
<(><<)>X4>6<(><<)>/X4>
/X0
The deserialization proceeds as follows:
In the first loop pass, element X1 is used and the first element X1 deserialized; ROOT1 is set to 1.
In the second loop pass, element X1 is used again because of condition tt:cond frq="*" and the second element X1 deserialized; ROOT1 is set to 2.
In the third loop pass, element X2 is used and the first element X2 deserialized; ROOT2 is set to 3.
In the fourth loop pass, element X2 cannot be used again because of condition tt:cond frq="?" . Instead, the second element X2
is skipped in the standard deserialization with tt:skip . Specifying count is necessary because otherwise all subsequent elements would be skipped.
In the fifth loop pass, element X3 is used and the first element X3 deserialized; ROOT3 is set to 5.
All required cases of the group have been selected, so the loop ends. Element X4 is deserialized outside of tt:group ; ROOT4
is set to 6.

SAP ST TT GROUP documentation, setup help and example usage