Buying, Reusing, or Building Components
Components can be bought from third-party vendors. If a third-party component can be found that performs the services you need, it is usually the most economical solution. On the other hand, third-party components typically perform a large number of services that you do not need and may not exactly fit the needs of your project. You must also verify that the maker of the product will update the component to accommodate new operating system and development program releases.
Reusing existing components is also an excellent option. Often the best way to make your component reusable is to carefully plan your system before you build it. With planning, you can often identify components of the system that can be used in many places. Sometimes an identical component can be used in numerous places; at other times only a part of the component can be used in multiple places.
In addition to reusing components, you can also reuse a component template. During the designing phase, you may find that some components can be built from a particular pattern. If you are building an order entry application, for example, you may find that all of your business services components perform the same CRUD functionality. Thus, all of your business services components have Create, Read, Update, and Delete methods. You can use this pattern of shared methods to create a template that can then be used to build all of your business services components with CRUD functionality.
Building a component is the most costly option in terms of time and resources, but with proper planning and design it will guarantee that the correct component is built. Using patterns and creating reusable components can offset the cost of designing and building components from the ground up.
The best option depends on the available resources. Finances, available personnel for development, and time allowed for development are the three most common resources that will influence your decisions. Each system should be carefully analyzed to find the best solution for that system.