Understanding servlet initialization and synchronization

Chapter 14 Working with Java

Understanding servlet initialization and synchronization

When creating a servlet, the initialization process instantiates the servlet class together with its methods.

The role of the synchronization is to maintain the coherence of the whole model whenever a change is applied. It occurs progressively between classes already attached to a component. PowerDesigner successively performs several actions to complete synchronization as the model is modified.

The initialization and synchronization of the servlet class works in a similar way as with Message Driven bean classes:

When the servlet class is attached to a servlet component, implementation methods for operations defined in the javax.servlet.Servlet interface are added by default. This interface is the base interface for all servlets, it may be included in the code depending on the servlet type selected. For HttpServlet and GenericServlet, the servlet class being directly derived from a class that implements it, it does not need to reimplement the interface. On the contrary, for user-defined servlets, this interface is implemented. You can see it from the Preview page of the servlet class.
Implementation methods are removed when the class is detached if their body has not been altered
The actual set of predefined methods vary depending on the servlet type

You can use the Check Model feature at any time to validate your model and complement the synchronization by selecting the Check Model feature from the Tools menu.