The <topicSubjectHeader> element specifies constraints on the subjects used in classifications.
You use the <topicSubjectHeader> element to supply a header row for a topic classification table when you want to encourage classification with subjects from different categories (also known as a facet classification). Each cell in the header row identifies the subject for a different category. The subjects in the same column within the classification rows must appear in the category in the subject scheme. For instance, if the cell within the header row specifies the Operating System category, the subjects in the column must be kinds of operating systems.
( (topicCell) then (subjectCell) (one or more) ) |
+ map/relrow classify-d/topicSubjectHeader
The topic subject table below classifies topics with goals for retrieval and with operating systems for filtering. The map makes use of definitions in a subject scheme map, defined separately.
<subjectScheme> <hasKind> <subjectdef href="goalType.dita" keys="goal"> <subjectdef href="performanceGoal.dita" keys="performance"/> <subjectdef href="reliabilityGoal.dita" keys="reliability"/> </subjectdef> <subjectdef href="operatingSystem.dita" keys="os"> <subjectdef href="linuxOS.dita" keys="linux"/> <subjectdef href="unixOS.dita" keys="unix"/> <subjectdef href="windowsOS.dita" keys="windows"/> </subjectdef> </hasKind> </subjectScheme>
The following <topicSubjectTable> classifies several topics according to subjects in the previous map. As with any <topicSubjectTable>, the first column is used to specify topics. In this specific example, the second column is used to specify a goal, based on the "goal" subject in the header. The third column is used to specify an operating system. Based on those definitions, the following classifications are made by this table:
<map> ... <topicSubjectTable> <topicSubjectHeader> <topicCell type="task"/> <subjectCell> <topicsubject keyref="goal"/> </subjectCell> <subjectCell> <topicapply keyref="os"/> </subjectCell> </topicSubjectHeader> <topicSubjectRow> <topicCell> <topicref href="webServerStart.dita" navtitle="Configuring cron for efficient startup"/> <topicref href="dbDisk.dita" navtitle="Allocating raw storage"/> </topicCell> <subjectCell> <topicsubject keyref="performance"/> </subjectCell> <subjectCell> <topicapply keyref="linux"/> <topicapply keyref="unix"/> </subjectCell> </topicSubjectRow> <topicSubjectRow> <topicCell> <topicref href="webLogAnalyze.dita" navtitle="Analyzing web logs for service issues"/> <topicref href="webDenialService.dita" navtitle="Detecting denial-of-service attacks"/> </topicCell> <subjectCell> <topicsubject keyref="reliability"/> </subjectCell> <subjectCell> <topicapply keyref="linux"/> <topicapply keyref="unix"/> <topicapply keyref="windows"/> </subjectCell> </topicSubjectRow> ... </topicSubjectTable> </map>
A table view of this <topicSubjectTable> might look as follows. This is only one of many possible views; to aid in understanding the example, the content topics in the first column are displayed using only their titles, and related subjects are displayed using only their keyref attribute value.
Configuring cron for efficient startup |
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Analyzing web logs for service issues |
univ-atts attribute group (includes select-atts, id-atts, and localization-atts groups) |
A set of related attributes, described in 3.4.1.3 univ-atts attribute group |
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A set of related attributes, described in 3.4.1.2 global-atts attribute group |
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A common attribute described in 3.4.1.9 Other common DITA attributes |