The decorator pattern is a design pattern that allows you to wrap an object such that it will appear to execute a given behavior in many different ways at different points in program execution. This is especially useful when you want an object to have different behaviors at but are unable to mutate the object. The decorator pattern is a useful way to implement dynamic behavior without needing an extended inheritance-based class hierarchy. To use the decorator pattern you need four elements: a component interface; a concrete component; a decorator abstraction; and, a concrete decorator. The interface sets the contract for both component and decorator behavior, the decorator abstraction contains a pointer to some concrete component, and the concrete decorators wrap a concrete component and override behavior if desired.
John Mansell Smith has been a self-employed painter & decorator for four years. He explains what it’s like to run your own business. “I became a self-employed painter & decorator when I took early retirement from my professional job in London, where I was employed as a Principal Building Surveyor. When I retired, I needed some additional income to supplement my pension, and having been in the building industry I was fully aware of the standard and quality which would be required to produce work to a professional standard. For a typical day at work, I usually arrive at the job at 8.30 am, and then depending on the sort of work I am doing it will vary a great deal. I could be undertaking external decorations or internal decorations, but in each case it would require covering and protecting the client's furniture, preparation of surfaces, washing down the walls, painting, wallpapering, cleaning up, etc. I try to leave at about 4.30 pm, but this may vary depending on the stage that I have reached with the job. In terms of likes and dislikes, I don’t enjoy working outside in poor weather, although I try to plan my workload to avoid this. However, I do like the freedom of being my own boss and getting complimented on a good job. If you wanted to be a painter and decorator, you would have to decide whether you wish to work for a company with the benefits such as holiday pay, but with the constraints of not being your own boss, or working for yourself with the freedom this gives but also the uncertainty of workload. As a self-employed person I can charge about £15 per hour for work that I do on an hourly rate, or I base any calculations on this rate when I am producing an estimate for a client. In attempting to find work, I would try the job centre, trade journals, large decorating companies, the internet and building training boards. To do the job you need to be a clean, neat worker with an eye for detail. The job you produce is the final result that the client will see, so it is vital that you can produce a finished job that you would be happy to have in your own home.
Syntactic constraints. Python is a syntactically simple language with fairly strong constraints on what can and can't be done without "messing things up" (both visually and with regards to the language parser). There's no obvious way to structure this information so that people new to the concept will think, "Oh yeah, I know what you're doing." The best that seems possible is to keep new users from creating a wildly incorrect mental model of what the syntax means.
Painters prepare surfaces of building and other structures and then apply paint by means of brushes, rollers or sprayers. They work with varnish, enamels, lacquer and other materials. They may also paint interior rooms or cover walls with paper, fabrics, vinyls or other materials (paperhanger). They must be able to mix paints as well as do sandblasting and waterblasting.
Painters must have manual dexterity as well as steady nerves to work in high places. They should not be allergic to or bothered by paint fumes, toxic materials and spray dust. They should have a certain artistic sense in order to do a first-class job. Good eyesight and sense of color is especially important to properly mix paint to specific colors.
Blakes is currently recruiting for a motivated Maintenance Assistant to join their Maintenance Department. As a Maintenance Engineer you will ensure the smooth running of engineering and maintenance operations within the hotel. This will include general property maintenance and energy conservation. Electrical Qualification Required Main Responsibilities: · Perform day-to-day routine and preventative maintenance within the hotel · Respond promptly and efficiently to any maintenance calls · Execute the preventative maintenance schedule and ensure all equipment and designated areas are maintained to the required standard · Assist in the implementation of energy conservation program · Recommend maintenance system improvements and energy savings · Maintain all tools, equipment, and working areas are in good condition · Keep your technical training knowledge and skills up to date · Ensure good relationships are built with internal and external customers · Ensure all duties comply with Company standards and Health and Safety sta
One of the other advantages of the decorator pattern is that wrapped objects can retain the type of the original object. As a result, you can use original and wrapped objects interchangeably, which is a significant advantage when your goal is to write flexible code. In this manner, you can easily extend the behavior of a particular object without modifying the original code.
Heller’s protagonist, Jim Stegner, is an unschooled but talented painter who struggles with drink, with womanizing, and with his temper. These traits have led him to be a killer, although Heller goes to great pains to let us know these acts are not premeditated. They’ve also, in accordance with these United States’ innate streak of violence, allowed him to be a cult figure - a talent around whom one feels it necessary to walk on eggshells. (For what it’s worth, this trait is to this reader and social observer the cause of a hollowness within the national psyche.) Stegner wants atonement for his acts, but he doesn’t know how to go about that. So Heller must allow Stegner to be the subject of retributive violence, which allows the painter, as might happen to a pre-adolescent child, to have atonement forced on him. Stegner is as a person and as a literary creation, a mess. Perhaps Heller intends him to be a faux Hemingway: hard drinking, bullying and a crybaby when those tables are turned on him. Stegner doesn’t seem to have the backbone about which an anti-hero’s fatal flaws can be built, though; he’s too much at the whims of fate for that. Heller tries to create philosophical depth for Stegner, but these attempts ring hollow. What he has created in Stegner, however, is a depiction of an instinctive artist, something the American psyche always seeks: talent and success untrammeled by subjecting that psyche to training and the lessons of culture and history. That Stegner is, in the end, a talented but pitiful figure, should tell the reader something very important: instinct that refuses at least a small measure of acculturation eventually become debased.
Note that greet_bob(say_hello) refers to two functions, but in different ways: greet_bob() and say_hello. The say_hello function is named without parentheses. This means that only a reference to the function is passed. The function is not executed. The greet_bob() function, on the other hand, is written with parentheses, so it will be called as usual.
There is general agreement that syntactic support is desirable to the current state of affairs. Guido mentioned syntactic support for decorators  in his DevDay keynote presentation at the 10th Python Conference , though he later said  it was only one of several extensions he proposed there "semi-jokingly". Michael Hudson raised the topic  on python-dev shortly after the conference, attributing the initial bracketed syntax to an earlier proposal on comp.lang.python by Gareth McCaughan .
Painters deal practically with pigments, so "blue" for a painter can be any of the blues: phthalocyanine blue, Prussian blue, indigo, Cobalt blue, ultramarine, and so on. Psychological and symbolical meanings of color are not, strictly speaking, means of painting. Colors only add to the potential, derived context of meanings, and because of this, the perception of a painting is highly subjective. The analogy with music is quite clear—sound in music (like a C note) is analogous to "light" in painting, "shades" to dynamics, and "coloration" is to painting as the specific timbre of musical instruments is to music. These elements do not necessarily form a melody (in music) of themselves; rather, they can add different contexts to it.