Thesis full text (PDF) - Politecnico di Milano

Through the entry unit in figure 4.1 we can create new user on the social network. When the user
presses the submit button, chain of operations is triggered: a new user instance is created and add
a property value to the instance called ID.
Figure 4.1: Example of WebML hypertext specification
The example in figure 4.2 shows the WebML model of a page called Create New Group,
allowing the user to create a new group. Through the entry unit the user can create a group in the
social network. The get unit retrieves the data of the current user from the session. When the user
submits, a chain of operations is triggered: a new Group instance is created and also add its
property and is associated to the current user (relationship creator, member) and to the current
Group (relationship membership, creation).
The WebML language is extensible, allowing for the definition of customized operations and
units. The WebML models are provided with primitives for representing Web Services
interactions [56][57], workflows constraints [58], context-aware behavior [59], and Semantic
Web Services [60]. WebML has been implemented in the tool WebRatio 3 [61], a C.A.S.E.
3 http://www.webratio.com
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