Quotes About Abstraction

We do not want to expose the details of our data. Rather we want to express our data in abstract terms. This is not merely accomplished by using interfaces and/or getters and setters. Serious thought needs to be put into the best way to represent the data that an object contains. The worst option is to blithely add getters and setters.

Don't override concrete functions. Concrete functions often require source code dependencies. When you override those functions, you do not eliminate those dependencies—indeed, you inherit them. To manage those dependencies, you should make the function abstract and create multiple implementations.

Never mention the name of anything concrete and volatile. This is really just a restatement of the principle itself.

This means that the UI and the database can be plugins to the business rules. It means that the source code of the business rules never mentions the UI or the database.

Objects hide their data behind abstractions and expose functions that operate on that data. Data structure expose their data and have no meaningful functions.

Resisting premature abstraction is as important as abstraction itself.

THE STABLE ABSTRACTIONS PRINCIPLE A component should be as abstract as it is stable.

The SAP and the SDP combined amount to the DIP for components. This is true because the SDP says that dependencies should run in the direction of stability, and the SAP says that stability implies abstraction. Thus dependencies run in the direction of abstraction.

ISP: The Interface Segregation Principle This principle advises software designers to avoid depending on things that they don't use.

The topmost parts of the source file should provide the high-level concepts and algorithms. Detail should increase as we move downward, until at the end we find the lowest level functions and details in the source file.

The source code of higher-level services must not contain any specific physical knowledge (e.g., a URI) of any lower-level service.

THE COMMON REUSE PRINCIPLE Don't force users of a component to depend on things they don't need.

But then closely related concepts should not be separated into different files unless you have a very good reason. Indeed, this is one of the reasons that protected variables should be avoided.

A good architecture makes it unnecessary to decide on Rails, or Spring, or Hibernate, or Tomcat, or MySQL, until much later in the project. A good architecture makes it easy to change your mind about those decisions, too. A good architecture emphasizes the use cases and decouples them from peripheral concerns

One of your jobs as an embedded software developer is to firm up that line. The name of the boundary between the software and the firmware is the hardware abstraction layer (HAL) (Figure 29.4). This is not a new idea: It has been in PCs since the days before Windows.

structured programming, object-orient programming, and functional programming.

Making the code read like a top-down set of TO paragraphs is an effective technique for keeping the abstraction level consistent.

We live at a certain level of abstraction; we interact as bodies, not cell colonies.

He was in that familiar state - not that the occasion mattered to seriously to him -- of incoherent ideas spreading outward without a center, so characteristic of the present, and whose strange arithmetic adds up to a random proliferation of numbers without forming a unit.

Is not art then a tool we employ to peel the kitsch off life? Layer by layer art strips life bare. The more abstract it gets, the more transparent the air is. Can it be that the farther it is removed from life, the clearer art becomes? What a backwards contention it is to claim that life is more important than art! Life is good as long as it holds up to art: That in life which cannot be employed for art's sake is kitsch!

Money is just an idea.

No hay espacio para la imaginación en la geometría.

Marilla somut gerçeÄŸin güvenli yolu dururken, soyutluÄŸun ÅŸüpheli patikalar?na girmeyecekti.

Computer science is no more about computers than astronomy is about telescopes.