Extending Web Page Composer 
You can extend Web Page Composer capabilities, using an API, as follows:
Enable connecting between content items in a page (“mashups”)
Implement a custom content provider
Extend the standard notification mechanism
Extend content handling capabilities
Implement new iView modes
This section provides detailed information about the main tasks you can perform with the Web Page Composer API, illustrated by code samples.
Experience in development of Java applications for the portal
Note
This section does not include API reference information, such as detailed descriptions of packages, interfaces, classes and members. This information is provided in the Javadoc at http://help.sap.com/javadocs.