In object-oriented programming, the decorator pattern is a design pattern that allows behavior to be added to an individual object, dynamically, without affecting the behavior of other objects from the same class. The decorator pattern is often useful for adhering to the Single Responsibility Principle, as it allows functionality to be divided between classes with unique areas of concern. The decorator pattern is structurally nearly identical to the chain of responsibility pattern, the difference being that in a chain of responsibility, exactly one of the classes handles the request, while for the decorator, all classes handle the request.
Concrete Decorator: Here we have two concrete decorators, ExcitedMessageDecorator and QuizzicalMessageDecorator, each of which descends from the abstract MessageDecorator class. However, these decorators do have special behavior in that they override the GetMessage and PrintMessage behaviors and enhance them by calling the base version from MessageDecorator (which in turn delegates to the relevant IMessage object) and then appending exclamations.
After 2.4a2 was released, in response to community reaction, Guido stated that he'd re-examine a community proposal, if the community could come up with a community consensus, a decent proposal, and an implementation. After an amazing number of posts, collecting a vast number of alternatives in the Python wiki , a community consensus emerged (below). Guido subsequently rejected  this alternate form, but added:
This decorator works by storing the time just before the function starts running (at the line marked # 1) and just after the function finishes (at # 2). The time the function takes is then the difference between the two (at # 3). We use the time.perf_counter() function, which does a good job of measuring time intervals. Here are some examples of timings:
Enamels are made by painting a substrate, typically metal, with powdered glass; minerals called color oxides provide coloration. After firing at a temperature of 750–850 degrees Celsius (1380–1560 degrees Fahrenheit), the result is a fused lamination of glass and metal. Unlike most painted techniques, the surface can be handled and wetted Enamels have traditionally been used for decoration of precious objects, but have also been used for other purposes. Limoges enamel was the leading centre of Renaissance enamel painting, with small religious and mythological scenes in decorated surrounds, on plaques or objects such as salts or caskets. In the 18th century, enamel painting enjoyed a vogue in Europe, especially as a medium for portrait miniatures. In the late 20th century, the technique of porcelain enamel on metal has been used as a durable medium for outdoor murals.
When we instantiate a SimpleMessage and then pass it to the various decorators, we now get new behavior. Moreover, since both the concrete component and the concrete decorators all implement / descend from IMessage, they are interchangeable as far as the program is concerned, meaning that we can loop over them together. Further, rather than having to create a new ExcitedAndQuizzicalMessageDecorator class, we were able to achieve the same effect by double wrapping a SimpleMessage object (first in an ExcitedMessageDecorator and then in a QuizzicalMessageDecorator). Finally, note that despite having been passed into various decorators, our simpleMsg object remains unchanged at the end of the program.
Aerosol paint (also called spray paint) is a type of paint that comes in a sealed pressurized container and is released in a fine spray mist when depressing a valve button. A form of spray painting, aerosol paint leaves a smooth, evenly coated surface. Standard sized cans are portable, inexpensive and easy to store. Aerosol primer can be applied directly to bare metal and many plastics.
Writing a class decorator is very similar to writing a function decorator. The only difference is that the decorator will receive a class and not a function as an argument. In fact, all the decorators you saw above will work as class decorators. When you are using them on a class instead of a function, their effect might not be what you want. In the following example, the @timer decorator is applied to a class:
This code works for our purposes but it’s not exactly dynamic. If we wanted our initial simpleMsg object to sometimes act excited and sometimes quizzical, we could only do so by instantiating entirely new objects from the relevant subclass. Moreover, the ExcitedAndQuizzicalMessage is really just a combination of ExcitedMessage and QuizzicalMessage and probably shouldn’t have its own class. To fix these problems, let’s now return to the decorator pattern and see how it might help us.
If working inside a person’s home, special attention will need to be paid to the different problems that can be encountered, such as those presented by pets and furniture. It is also essential to respect the private space of the client, and to work appropriately within it. If working for a construction firm, dangerous situations can be encountered, such as working at heights and employing the use of safety harnesses and ropes. Working outside brings with it its own hazards and difficulties, and the worker will need to plan for these accordingly through the types of clothing worn and the equipment used. The days can be long, and the hours can vary significantly. If self-employed, planning is essential to fit in as many jobs as is appropriate for the week, in order to avoid long spells of little work, or booking too many jobs into a short period of time. It is also possible that some jobs will require unsociable hours of work, such as working at the weekend. Although the profession is traditionally male dominated, more women are now being encouraged into the trade.
Maintenance Assistant We are a serviced apartments operator with apartments dotted around primarily around the EC postcode in London. The team is vibrant, multicultural and friendly. Due to continued success and ambitious growth we are actively seeking to appoint a Maintenance Assistant to join the maintenance team who are responsible for ensuring that the apartments and the appliances are in immaculate condition. Key Responsibilities our Maintenance Assistant: Preventive and reactive maintenance Maintain the appearance of apartments; replacing broken lamps, bedroom fixtures, fittings, carrying out general repairs, moving furniture, maintaining high standards of decor Carry out short term maintenance work e.g. decorating, painting and quick repairs Work closely with all departments and be able to communicate with guests when asked To work continually with guest relations, ensuring apartments are ready for guests’ arrival Travel in and around central London either on your own or with the maintenance team Report directly to the maintenance manager Use, operate and store all tools, equipment and materials safely and securely to comply with statutory regulations e.g. COSHH Ensure that the Health and Safety regulations are always adhered to Ad hoc duties
To calculate the tenth Fibonacci number, you should really only need to calculate the preceding Fibonacci numbers, but this implementation somehow needs a whopping 177 calculations. It gets worse quickly: 21891 calculations are needed for fibonacci(20) and almost 2.7 million calculations for the 30th number. This is because the code keeps recalculating Fibonacci numbers that are already known.
Style is used in two senses: It can refer to the distinctive visual elements, techniques and methods that typify an individual artist's work. It can also refer to the movement or school that an artist is associated with. This can stem from an actual group that the artist was consciously involved with or it can be a category in which art historians have placed the painter. The word 'style' in the latter sense has fallen out of favor in academic discussions about contemporary painting, though it continues to be used in popular contexts. Such movements or classifications include the following:
Painting is an important form in the visual arts, bringing in elements such as drawing, gesture (as in gestural painting), composition, narration (as in narrative art), or abstraction (as in abstract art). Paintings can be naturalistic and representational (as in a still life or landscape painting), photographic, abstract, narrative, symbolistic (as in Symbolist art), emotive (as in Expressionism), or political in nature (as in Artivism).