Mechanism for webpage composition

1. A method for webpage composition, comprising:

during development of a web application, receiving a first request for a webpage for a first business object type, the first request comprising a first business object type identifier of the first business object type;

receiving a first expression for selecting an instance of the first business object type from a plurality of instances of the first business object type from an object data source, the first expression specifying a first data source and an activity fragment; and

generating the webpage, the webpage comprising a first user interface (UI) widget for the first business object type and a first instruction for prepopulating the first UI widget with first data from the instance of the first business object type, the first instruction including the first expression, the first expression executable to perform a sequence of actions, the sequence of actions including the activity fragment, on data from the first data source to generate a result identifying the instance of the first business object type to use to prepopulate the first UI widget.

2. The method of claim 1 , wherein the sequence of actions comprises an action flow.

3. The method of claim 2 , wherein the sequence of actions comprises actions by which a user is guided using the web application accessing the webpage.

4. The method of claim 1 , further comprising obtaining the first instruction via an expression infrastructure interposed between the webpage and a data repository which stores the object data source, obtaining data from the object data source, and executing the first expression based on the data from the object data source to obtain the result.

5. The method of claim 4 , further comprising receiving an event via an event bus, and calling the expression infrastructure to perform an action requested by the event.

6. The method of claim 1 , wherein the first data source comprises a data repository.

7. The method of claim 1 , wherein the first data source comprises returned data for the instance of the first business object type.

8. The method of claim 1 , wherein the first data source comprises a portion of the webpage.

9. The method of claim 8 , wherein the portion of the webpage comprises a text field.

10. The method of claim 8 , wherein the portion of the webpage comprises a drop down menu option.

11. The method of claim 1 , wherein the first expression is encapsulated in an instruction for the first UI widget, and wherein generating the webpage comprises dragging and dropping the first UI widget into a web application design and entering parameters for one or more fields associated with the first UI widget.

12. A system, comprising:

a processor;

a memory coupled to the processor, the memory storing computer readable program code comprising instructions for:

during development of a web application, receiving a first request for a webpage for a first business object type, the first request comprising a first business object type identifier of the first business object type;

receiving a first expression for selecting an instance of the first business object type from a plurality of instances of the first business object type from an object data source, the first expression specifying a first data source and an activity fragment; and

generating the webpage, the webpage comprising a first user interface (UI) widget for the first business object type and a first instruction for prepopulating the first UI widget with first data from the instance of the first business object type, the first instruction including the first expression, the first expression executable to perform a sequence of actions, the sequence of actions including the activity fragment, on data from the first data source to generate a result identifying the instance of the first business object type to use to prepopulate the first UI widget.

13. The system of claim 12 , wherein the first data source comprises returned data for the instance of the first business object type.

14. The system of claim 12 , wherein the first data source comprises a portion of the webpage.

15. The system of claim 12 , wherein the sequence of actions comprises an action flow.

16. The system of claim 12 , wherein the sequence of actions comprises actions by which a user is guided using the web application accessing the webpage.

17. A computer program product comprising a non-transitory computer readable medium storing computer readable program code, the computer readable program code comprising instructions for:

during development of a web application, receiving a first request for a webpage for a first business object type, the first request comprising a first business object type identifier of the first business object type;

receiving a first expression for selecting an instance of the first business object type from a plurality of instances of the first business object type from an object data source, the first expression specifying a first data source and an activity fragment; and

generating the webpage, the webpage comprising a first user interface (UI) widget for the first business object type and a first instruction for prepopulating the first UI widget with first data from the instance of the first business object type, the first instruction including the first expression, the first expression executable to perform a sequence of actions, the sequence of actions including the activity fragment, on data from the first data source to generate a result identifying the instance of the first business object type to use to prepopulate the first UI widget.

18. The computer program product of claim 17 , wherein the sequence of actions comprises an action flow.

19. The computer program product of claim 18 , wherein the sequence of actions comprises actions by which a user is guided using the web application accessing the webpage.

20. The computer program product of claim 17 , wherein the first data source comprises returned data for the instance of the first business object type.