How do you protect your object's integrity?

2 Validate your inputs and outputs

Another way to protect your object's integrity is to validate your inputs and outputs, which means checking the validity and correctness of the data that your object receives or returns. By validating your inputs and outputs, you can ensure that your object's state and behavior are consistent with the expected rules and logic of your design. You can perform validation by using assertions, exceptions, or conditional statements to verify the preconditions and postconditions of your methods. For example, in Python, you can use the assert keyword to test if an input or output meets a certain condition and raise an AssertionError if not.

3 Use immutable objects

A third way to protect your object's integrity is to use immutable objects, which means creating objects that cannot be changed once they are instantiated. By using immutable objects, you can avoid the risks of unintended side effects, concurrency issues, or memory leaks that may arise from modifying mutable objects. You can create immutable objects by making your data fields final, using constructors or static factory methods to initialize them, and avoiding setter methods or other methods that may alter their state. For example, in C#, you can use the readonly keyword to declare your data fields as immutable and assign them only in the constructor.

4 Follow the principle of least privilege

A fourth way to protect your object's integrity is to follow the principle of least privilege, which means granting the minimum level of access or authority that is required for your object to function properly. By following the principle of least privilege, you can reduce the exposure and vulnerability of your object to potential threats or errors that may compromise its integrity. You can apply the principle of least privilege by using the most restrictive access modifiers, avoiding global or static variables, limiting the scope and lifetime of your variables, and minimizing the dependencies and interactions of your object with other objects or external sources.

5 Design by contract

A fifth way to protect your object's integrity is to design by contract, which means defining the formal and explicit specifications and obligations of your object and its clients. By designing by contract, you can establish a clear and mutual understanding of the roles and responsibilities of your object and its clients and ensure that they adhere to the agreed-upon terms and conditions. You can implement design by contract by using annotations, comments, or documentation to specify the preconditions, postconditions, and invariants of your object and its methods. For example, in Java, you can use the @Contract annotation to indicate the expected input and output values and behavior of your methods.

6 Test your code

A sixth way to protect your object's integrity is to test your code, which means verifying and validating that your object works as intended and meets the requirements and expectations of your design. By testing your code, you can detect and correct any errors or defects that may affect your object's integrity and ensure that your object delivers the desired functionality and performance. You can test your code by using various testing techniques and tools, such as unit testing, integration testing, regression testing, code coverage, debugging, or code review.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?