Databases
StackOverflow2013
Postsdbo
POHow to decorate an object method?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to decorate an object method?
    primarykey
    data
    text
    <p>I need to decorate a object's method. It needs to be at runtime because the decorators applied on the object depends on the arguments that the user gave when calling the program (arguments supplied with argv), so a same object could be decorated 3 times, 2 times, or not be decorated at all.</p> <p>Here is some context, the program is a puzzle solver, the main behavior is to find a solution for the puzzle automatically, by automatically I mean without user intervention. And here is where the decoration gets to play, one of the things I want to is draw a graph of what happened during the execution, but I want to do so only when the flag <code>--draw-graph</code> is used.</p> <p>Here is what I've tried:</p> <pre><code>class GraphDecorator(object): def __init__(self, wrappee): self.wrappee = wrappee def method(self): # do my stuff here self.wrappee.method() # do more of stuff here def __getattr__(self,attr): return getattr(self.wrappee,attr) </code></pre> <p>And why it did NOT work: It did not work because of the way I built the application, when a method that did not exist in my Decorator class was called it felt back to the implementation of the decorated class, the problem is that the application always started invoking the method <code>run</code> that did not need to be decorated, so the undecorated fall back was used and from inside the undecorated form it always called <strong>undecorated</strong> methods, what I needed was to replace the method from the object, not to proxy it:</p> <pre><code># method responsible to replace the undecorated form by the decorated one def graphDecorator(obj): old_method = obj.method def method(self): # do my stuff here old_method() # do more of my stuff setattr(obj,'method',method) # replace with the decorated form </code></pre> <p>And here is my problem, the decorated form does not receive <code>self</code> when it is called resulting on a TypeError because of the wrong number of arguments.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USagf
    1. USAugusto Hack
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to decorate an object method?
      1. This table or related slice is empty.
      1. VTDownMod
    2. VO
      singulars
      1. POHow to decorate an object method?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COpossible duplicate of [Implementing the decorator pattern in Python](http://stackoverflow.com/questions/3118929/implementing-the-decorator-pattern-in-python)
      singulars
      1. POHow to decorate an object method?
      1. USBjörn Pollex
    2. COSpace_C0wb0y - I have a problem with `__getattr__`, the class A is the class decorated by the class B, A has a method run() that calls method do(), the class B decorated the method do(), but because I use recursion within run() and I start it from class A method's run(), it calls it's own version of do(), and not the decorated one.
      singulars
      1. POHow to decorate an object method?
      1. USAugusto Hack
    3. COYour question could do with some clarifications, but if I read it correctly, you want to "hack" into some already written code in another module, so that it instantiates a modified object instead of the one it usually uses. If so, [this answer](http://stackoverflow.com/questions/3464061/cast-base-class-to-derived-class-python-or-more-pythonic-way-of-extending-classe/4714744#4714744) will tell you a way to do that.
      singulars
      1. POHow to decorate an object method?
      1. USLauritz V. Thaulow
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload