Quotes About Components

The Reuse/Release Equivalence Principle (REP) is a principle that seems obvious, at least in hindsight. People who want to reuse software components cannot, and will not, do so unless those components are tracked through a release process and are given release numbers.

Classes and modules that are grouped together into a component should be releasable together. The fact that they share the same version number and the same release tracking, and are included under the same release documentation, should make sense both to the author and to the users.

The architecture of a software system is the shape given to that system by those who build it. The form of that shape is in the division of that system into components, the arrangement of those components, and the ways in which those components communicate with each other.

THE COMMON CLOSURE PRINCIPLE Gather into components those classes that change for the same reasons and at the same times. Separate into different components those classes that change at different times and for different reasons.

This is the Single Responsibility Principle restated for components. Just as the SRP says that a class should not contain multiples reasons to change, so the Common Closure Principle (CCP) says that a component should not have multiple reasons to change.

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

Architects separate functionality based on how, why, and when it changes, and then organize that separated functionality into a hierarchy of components.

The OCP is one of the driving forces behind the architecture of systems. The goal is to make the system easy to extend without incurring a high impact of change. This goal is accomplished by partitioning the system into components, and arranging those components into a dependency hierarchy that protects higher-level components from changes in lower-level components.

The diagram in Figure 14.5 shows X, which is a stable component. Three components depend on X, so it has three good reasons not to change. We say that X is responsible to those three components. Conversely, X depends on nothing, so it has no external influence to make it change. We say it is independent.

When the I metric is 1, it means that no other component depends on this component (Ca = 0), and this component does depend on other components (Ce > 0). This is as instable as a component can get; it is irresponsible and dependent. Its lack of dependents gives it no reason not to change, and the components that it depends on may give it ample reason to change.

Notice how well those three align with the three big concerns of architecture: function, separation of components, and data management.

both are key components of what is commonly referred to as classroom management (Marzano et al., 2003). A case can be made that if strategies for these two elements are not in place, a teacher will have little control of the classroom.

The first step to creating something was to figure out its parts. Master Luhhan had taught Perrin that on his first day at the forge. You couldn't make a spade without understanding how the handle fit to the blade. You couldn't make a hinge without knowing how the two leaves moved with the pin. You couldn't even make a nail without knowing its parts: head, shaft, point. Understand the pieces, Perrin.

A complex assembly is best described first in terms of its substances: its subassembles and parts. Then, next, it is described in terms of its methods: its functions as they occur in sequence.

In a reductionist view, understanding something complex requires breaking it down into its components; understand those parts, add them together, and you'll understand the big picture. And in this reductionist world, to understand cells, organs, bodies, and behavior, the best constituent part to study is genes.

The second type is an investor who creates investments. This investor usually assembles a deal in the same way a person who buys components builds a computer. I do not know the first thing about putting components of a computer together, but I do know how to put pieces of opportunities together, or know people who know how.

Indeed, these lenses and compasses are perhaps the most important components of America's unwritten Constitution, and they form the organizational spine of this book. Fair

It's cheaper to put an entire microprocessor in your car key, microwave, or cell phone than it is to put in discrete chips and electronic components. Thus, a new technical economy drives the design of the product.

Really, it's just a question of reassembling the components in the correct sequence...

While neurological studies have tried to identify components responsible for fear and greed, the impact on finance is less clear.

Cuando uno comete un gran error», reflexionaría filosóficamente, «es muy fácil que acabe revelándose de mayor utilidad que la más acertada de las decisiones. La vida es un todo indivisible, y la suerte también, y ninguno de sus componentes puede separarse del resto».

the three fundamental types of production operations: process manufacturing, an activity that physically or chemically changes material just as boiling changes an egg; assembly, in which components are put together to constitute a new entity just as the egg, the toast, and the coffee together make a breakfast; and test, which subjects the components or the total to an examination of its characteristics.

Little things do matter. Sometimes, little things matter the most. Everybody pays a lot of attention to big things, but nobody seems to understand that big things are almost always made up of little things. When you ignore little things, they often turn into big things that have become a lot harder to handle.

As soon as I left school at 16, I worked in a factory making aircraft components.