2. Reflection
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 2 / 10

3. Terminology
Introspection—self-representation can be queried.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 3 / 10

4. Terminology
Introspection—self-representation can be queried.
Intercession—self-representation can be changed.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 3 / 10

5. Terminology (II)
Structural reflection—concerned with structure.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 4 / 10

6. Terminology (II)
Structural reflection—concerned with structure.
Behavioral reflection—concerned with execution.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 4 / 10

7. Reflection in Object Languages
Everything is an object.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 5 / 10

8. Purpose
Tools.
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 6 / 10

9. Alternative
Source code
Byte code
AST
Custom represenation
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 7 / 10

10. Metadata
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 8 / 10

11. What Is Metadata?
Field and method names
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 9 / 10

12. What Is Metadata?
Field and method names
Class names
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 9 / 10

13. What Is Metadata?
Field and method names
Class names
Various modifiers
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 9 / 10

14. What Is Metadata?
Field and method names
Class names
Various modifiers
Even type information
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 9 / 10

15. What Is Metadata?
Field and method names
Class names
Various modifiers
Even type information
More or less anything that is not compiled into binary
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and Metadata December 14, 2010 9 / 10

16. Is Metadata Used Outside of Source Code?
Yes
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and MetadataDecember 14, 2010 10 / 10

17. Is Metadata Used Outside of Source Code?
Yes
Whenever we are referring to a class we are supplying it with an
additional information
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and MetadataDecember 14, 2010 10 / 10

18. Is Metadata Used Outside of Source Code?
Yes
Whenever we are referring to a class we are supplying it with an
additional information
Why don’t we include metadata in the source code? Is it possible?
Michal P´se (CTU in Prague)
ıˇ Object Programming Lect. 12: Reflection and MetadataDecember 14, 2010 10 / 10