Forms of LoD

1
Forms of LoD
forms class (c) object (o)
static(s), Prog. Anal. useful (c/s), simple definition useful (o/s), approximates o/d
dynamic(d), AspectJ not useful (c/d), c/s instead most useful (o/d), simple definition
2
Notes

• o/s if an illegal message sending is possible
  assuming each decision taken both ways and each
  loop is executed 0 or more times.
• c/d not interesting, because c/s. If
  dynamically do o/d

3
Note

• The following aFoo.getPart().getPart().
• getBar().getBp().test()
• Should not be allowed in a static method.
• Next follows a generalization of LoD to
• static methods (slide after next). Do you agree?
  

4
Object form for regular methods

• Within a method, messages can only be sent to the
  following objects
• 1. A parameter of the method, including the
  enclosing object
• (this or self)
• 1.1. For pragmatic reasons a global object
• 2. An immediate part object (computed or stored)
  
• 2.1 An object that a method called on the
  enclosing object returns, including attributes of
  the enclosing object
• 2.2 An element of a collection which is an
  attribute of the enclosing object
• 3. An object created within the method.

5
Object form for static methods

• Within a static method, messages can only be sent
  to the following objects
• 1. A parameter of the method, including the
  current class
• 1.1. For pragmatic reasons a global object
• 2. An immediate static part object (computed or
  stored)
• 2.1 An object that a static method called on the
  current class returns, including static
  attributes of the current class
• 2.2 An element of a collection which is a static
  attribute of the current class
• 3. An object created within the method.