Code reuse

Code reuse is a sought-after goal, but it does not happen automatically. It costs money, and it requires explicit attention at the level of design and in the structure of the development process within and across projects. 

Naturally, the organization that measures developer productivity in terms of lines of code written has some rethinking to do before reuse can succeed. Suitable incentives schemes should be based more on the ratio of code reused to new code written. 

The framework approach to code reuse provides a concrete, yet incomplete, implementation of the architecture The rules and policies about how application objects interact are codified and enforced by the framework itself. Frameworks can be both white-box—a template method in the superclass must be overriden by a subclass after understanding the calls made in the superclass implementation—and black-box, in which interfaces for the plug-in calls are explicitly specified and implemented according to the spec. 

There are different types of code reuse. Here we focus on code reuse using a class hierarchy—in other words, through inheritance. 

Notice that now each of these two classes extends Molstructure class and all common code is removed from them. This result is because the common behaviors are inherited from the common superclass—Molstructure. Also notice that even some logic in the constructor is inherited from the superclass. Now we have achieved some code reuse through inheritance by having a class hierarchy. 

Service-oriented architecture (SOA) is a hot topic these days and is considered by many people to be the enterprise computing framework of the future. In SOA, each software unit runs on a piece of hardware as a service that can be called by many different consumers. For example, a compound registration service can be called by a library enumeration tool and a chemistry e-notebook to fulfill compound registration tasks. The most popular SOA is Web services that are based on HTTP and XML or SOAP standards although SOA as a concept has existed for awhile and is not limited to Web services. SOA has a lot of advantages, the most important of which is code reuse and improved productivity. However, it also presents a lot of challenges. 

There are two types of code reuse one is code libraries that are deployed with every single application that uses them. Another is services that are deployed and run independently somewhere in the network. The notion of designing with SOA in mind is very important. Service is not about simply wrapping a piece of code that is designed for a standalone application with a service API and exposing it to the public. It represents unique requirements and challenges such as the following ... 

There is always a better way. One thing can be improved in the above design. Since executeAlIRules() should be the same no matter what vendor tool is used, it could be put into an abstract base class that all implementation classes extend to enhance code reuse. 

A few abstract protected methods are left to the concrete mapper object to implement. They are declared in AbstractMapper so that they can be called by the Template Methods to maximize code reuse. 

OOP also makes code reuse easier than structured programming allows. In a structured environment, if you need to perform a task that is similar but not identical to an existing function, you must create a new function from scratch. You might copy the code from the original function and use it as a foundation, but the functions will generally be independent. This approach is error-prone and makes long-term program maintenance difficult. In OOP, one may use a principle called inheritance... 

Code reuse (computer programming), 71-72 Codesign, 604, 606 Coding (group technology), 461-462 Cogeneration (energy), 1577... 

Third-party integration and code reuse. Standard software, such as GUI builders or hbraries, is integrated. 

---