Notation

In case you're having a hard time following the notation used throughout this site, here's the legend:

IFoo = interface //IFoo is an interface
  //Foo is a procedure method of IFoo
  procedure Foo;
  //Bar is a function method of IFoo that returns an integer
  function Bar: integer; 
  //FooBar is a procedure with 2 parameters
  procedure FooBar (Param1, Param2);  
end; //denotes end of IFoo interface

IBar = interface (IFoo) //IBar inherits from IFoo
end;

FooClass = class (
  //denotes class FooClass inherits from class BaseClass
  BaseClass,
  //and implements interface IFoo
  IFoo)
end;

//denotes an implementation of IFoo.Foo in class FooClass
procedure FooClass.Foo;
begin
  ... //IFoo.Foo implementation body
end;

//denotes implementation of IFoo.Bar in class FooClass
function FooClass.Bar: integer;  
begin
  Result = 10; //IFoo.Bar returns 10 as function result
end;

For Delphites, this notation may look very familiar because it's Pascal. 

Also, most diagrams are based on the Unified Modeling Language (UML). If you're not familiar with UML, you can visit Rational at www.rational.com/uml/index.jtmpl.