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Tuesday Dec 12, 2006

F3 Reflection and Query operators

A friend of mine who works at MIT libraries recently showed me a neat little AJAX data visualization program they developed called Exhibit.

This seemed like a good test case for F3 reflection and for its query operators, so I decided to try to see how hard it would be to do the same kind of thing in F3.

Below is a (partial) F3 equivalent of this Exhibit example.

The above demo also displays the F3 source code.

This is actually a plain Swing program (the F3 Canvas isn't used), but demonstrates the use of HTML templating with F3.

All of the filtering and sorting is actually done in 3 lines of code (take a look at DB.f3 and AttributeValueAssertion.f3).

Some things to note:

Attribute is an F3 reflection class analagous to java.lang.reflect.Field

Reflective access to the value of an attribute uses the [] operator with an operand of type Attribute, e.g.

   var bar = foo.class.Attributes[Name == 'bar'];
   foo[bar] = 2;
   // The above is analogous to the following Java code
   // Field bar = foo.getClass().getField("bar");
   // bar.set(foo, 2);

is the reflective equivalent of

   foo.bar = 2;

The F3 order by operator is a binary operator. The left-hand side is any list of objects. The right-hand side is an expression that must return a list of comparable objects. The right-hand expression is evaluated in the context of each element of the left hand side. The current element can be accessed with the . (dot) operator (as in XPath).
For example,
```
   [1, 2, 3] order by -.
```
yields
```
   [3, 2, 1]
```

Posted at 06:41PM Dec 12, 2006 by Christopher Oliver in F3 | Comments[16]

Comments:

Very interesting stuff! But where to get F3? regards esser

Posted by esser on December 13, 2006 at 04:22 AM PST #

yeah F3 is great ,being a harcore swing programmer i wish to try F3 myself before i can recommend... when do u plan to release the F3 compiler/interpreter...and what abt the netbeans /eclipse plugins that u spoke off.

Posted by Pavan Kumar Srinivasan on December 13, 2006 at 05:05 AM PST #

Oh Chris, you'll killing us. We're itching to get using F3. F3Pad is tiding me over, but I looking forward to the release. These examples are amazing as well.

Posted by Tyler Weir on December 13, 2006 at 06:04 AM PST #

The ajax page does have one leg up on your swing application, IMO. The various filters available on the left hand side work much better as a stack of boxes (the web version) than a series of tabs (the f3 version), especially in Java 5 with the default look and feel on a windows machine.' Keep up the great work! -Andrew

Posted by Andrew on December 13, 2006 at 10:12 AM PST #