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The SEDRIS Data Representation Model
APPENDIX A - Classes Attribute Set Index Control Link |
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An instance of this DRM class specifies an <Expression> that determines the index field value of all target <Attribute Set Index> instances, thus controlling which <Attribute Set> is referenced by each such <Attribute Set Index>.
Note that since each controlled <Attribute Set Index> may be bound to a different <Attribute Set Table Group>, and thus to a different primary <Attribute Set Table>, the fact that their index values are the same does not mean that the set of <Attribute Set Index> instances controlled by a given <Attribute Set Index Control Link> reference the same <Attribute Set>.
A tree canopy appears different at different times of the year, with a different colour and texture. This could be achieved by using a different <Attribute Set> for each period of the year. Each <Attribute Set> would contain the appropriate <Colour> and <Image Mapping Function>. An <Attribute Set Index Control Link> would be used to allow the appropriate <Attribute Set> to be selected.
An <Attribute Set Index Control Link> controls the value of the index stored in the <Attribute Set Index> instances that reference it.
No. The index always refers to the primary <Attribute Set>.
No. The link to the <Attribute Set Table Group> is an association within the transmittal, and associations cannot be changed dynamically.
| SE_String | description; | (notes) |
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| SE_Integer_Positive | expr_index; | (notes) |
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This is a text description of the given <Control Link> instance's purpose.
This specifies the component <Expression>, the value of which controls the index of the affected <Attribute Set Index>.
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