Substituting an extended View Link allows any changes made to the original View Link, such as code added to the View Link's XML file or new source and destination objects, to be made available to all of its instances in the rest of the application. If you substitute the extended View Link, then you must ensure that the extended View Objects it connects (and the extended Entity Objects they reference) are also substituted. This is because the extended View Objects will typically have new attributes that do not exist in the originals. Also, the View Link might use these new attributes in its definition of the source and destination role attributes, and in the View Link query's WHERE clause.
Figure 1: Substituting an Extended View Link
As Figure 1 illustrates, assume that when you extended the Emp Entity, you added a Loc (location) attribute. This attribute will be added to the query when you create the extended View Object NewEmpViewEx. Loc is already an attribute of DeptView, and will automatically be included in the query of the extended View Object NewDeptViewEx. Then when you create the extended View Link between NewEmpViewEx and NewDeptViewEx you can add Loc to the lists of source and destination role attributes, and also to the WHERE clause of the View Link query. If you then substitute the extended View Link into the application, you must also substitute NewEmpEx and NewEmpViewEx (because Emp and EmpView do not have a Loc attribute) and NewDeptEx and NewDeptViewEx (because Dept does not recognize Loc as a source role attribute).
Use the Substitutions panel of the Business Components Project wizard to substitute the extended View Links throughout your application. For the procedure to substitute a View Link, see To Substitute Business Components. The framework makes an addition to the Substitutes section of the project's .jpx file which identifies the name of the original View Link and the name of the extended View Link that should be used instead.
For example, if you use the Substitutions panel of the Business Components Project wizard to substitute the extended View Link NewFKLinkEx for the original View Link EmpForeignKeyLink throughout your application, the framework adds a line to the Substitutes section of the project's XML file. A portion of the project's XML file is included below:
<Substitutes>
<Substitute OldName ="package27.DeptView" NewName ="Extender.NewDeptViewEx" />
<Substitute OldName ="package27.EmpView" NewName ="Extender.NewEmpViewEx" />
<Substitute OldName ="package27.Emp" NewName ="Extender.newEmp" />
<Substitute OldName ="package27.EmpForeignKeyAssoc" NewName ="Extender.NewFKAssocEx" />
<Substitute OldName ="package27.Dept" NewName ="Extender.NewDeptEx" />
<Substitute OldName ="package27.EmpForeignKeyLink" NewName ="Extender.NewFKLinkEx" />
</Substitutes>
Note that is is assumed that you have already substituted the extended Entity Objects NewEmpEx and NewDeptEx for the original Entities Emp and Dept, and the extended View Objects NewEmpViewEx and NewDeptViewEx for the original Views EmpView and DeptView in the project file.
Note also that extending and substituting the Association between the extended Entity Objects is optional and has no effect on the extended View Link between the Views.