Then the code you write should have the following qualities. Code should be
- Transparent The consequences of change should be obvious in the code that is changing and in distant code that relies upon it
- Reasonable The cost of any change should be proportional to the benefits the change achieves
- Usable Existing code should be usable in new and unexpected contexts
- Exemplary The code itself should encourage those who change it to perpetuate these qualities
Code that is Transparent, Reasonable, Usable, and Exemplary (TRUE) not only meets today’s needs but can also be changed to meet the needs of the future. The first step in creating code that is TRUE is to ensure that each class has a single, well-defined responsibility.