Web Dynpro Phase Model

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Web Dynpro Phase Model
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Web Dynpro Phase Model

• The request/response cycle also called a server
  roundtrip is divided into phases
• The cycle is stateless meaning all the objects
  created for the cycle are destroyed when the
  cycle is completed and nothing carries over from
  one cycle to the next

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Web Dynpro Phase Model
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Phase Model

• Data Transport into the Data Container
• Beginning of the cycle, data of the
  client-specific data format is transported into
  the client-independent Web Dynpro data container
• Transport of Modified Data into the Context
• Data in the data container is string based
• Data must be parsed and converted into
  type-specific format before being transported
  into the context

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Phase Model

• Validating Modified Data
• Once data is parsed a validation check is
  performed
• The value is checked for semantic correctness
  validity of key values, correct formatting
  defined by data type metadata
• If an action is triggered, the subsequent phase
  action event handler is called

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Phase Model

• System Event Handler
• System requests are events that do not involve
  the application
• A typical system request is logoff
• Service Event Handler
• Service events are events that involve the
  application but are processed in the WDF
• Typical system events are load-on-demand and
  paging in a table UI
• After handling service events wdDoBeforeNavigation
  () and wdDoPostProcessing() are called

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Phase Model

• Action Event Handler
• Action event handlers of the application are
  called
• Event handler with validation are only called if
  no data errors occurred
• Validation errors are displayed on the user
  interface
• Outbound action event handlers are called
• All outbound plugs are collected in a navigation
  list

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Phase Model

• Navigation Preparation wdDoBeforeNavigation()
• Standard hook method that allows the developer to
  perform processing before navigation occurs
• Can be used to validate user input
• Navigation
• Web Dynpro runtime processes outbound plugs
  contained in the navigation list and calls the
  event handler of the corresponding inbound plugs

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Phase Model

• Dynamic UI Manipulation wdDoModifyView()
• Standard hook method is called for all views in
  the view assembly
• Can be used to manipulate the view layout
• Postprocessing of Errors wdDoPostProcessing()
• Standard hook method is called after navigation
• Can be used to fix data validation errors
• Response Rendering