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The <dlm:fragment> element has four possible attributes, one optional or more nested <dlm:role> element elements (see Roles Defined), and zero to many nested <dlm:audience> elements or comments. The audience elements indicate to whom the fragment will go. See Audiences Defined for more detail.
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The roles element determines to what group a fragment owner will belong. Multiple role elements for a fragment means that the fragment owner is a member of each of these groups. The fragment owner is defined by the ownerID attribute of the containing fragment element and represents the user account whose layout is used as the layout for the fragment. When modifying the layout, channels can be added. Channels are themselves granted only to certain groups of users. As such there is the potential for a fragment owner to have one set of group membership memberships and the users of that fragment to have other disjoint group memberships. In such cases channels added to the surface of that layout and them merged into the user's layouts will show up as broken and indicate that the user does not have access to that channel.
The role element is a step toward resolving such problems. Upon loading dlm.xml the infrastructure looks to see what groups the fragment owner is a member and removes them from all groups except the one ones indicated by the nested role elementelements. Additionally, if they are not a member of this group these groups then they are made a member of that groupeach.
New features slated to be added as part of the ALM Convergence effort will render this declaration unnecessary. The goal is for the fragment editing UI to indicate which channels added to the fragment may not be available to all users of the fragment as defined by the set of users to whom the fragment is published for pushed fragments or the users who can subscribe to the fragment for pulled fragments.
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