All Flashcards
What are the differences between accessor and mutator methods?
Accessor: Retrieves the value of an instance variable. | Mutator: Modifies the value of an instance variable.
Compare a class with only accessor methods vs. a class with only mutator methods.
Accessor-only: Exposes data, read-only. | Mutator-only: Allows modification, no direct data access.
What are the differences between using direct access to instance variables and using mutator methods?
Direct access: Simple, but violates encapsulation. | Mutator methods: Encapsulated, allows validation, more controlled.
Compare the use of void vs. non-void mutator methods.
Void: No return value, modifies only. | Non-void: Can return previous value or status, allows chaining.
What are the differences between immutable and mutable objects?
Immutable: Cannot be changed after creation. | Mutable: Can be changed after creation via mutator methods.
Compare the use of mutator methods with and without validation.
Without validation: Faster, but can lead to invalid state. | With validation: Slower, but ensures data integrity.
What are the differences between public and private mutator methods?
Public: Accessible from anywhere. | Private: Only accessible within the class, used for internal state management.
Compare the use of mutator methods in single-threaded vs. multithreaded environments.
Single-threaded: Simpler, no need for synchronization. | Multithreaded: Requires synchronization to prevent race conditions.
What are the differences between using mutator methods and using reflection to modify object state?
Mutator methods: Safe, controlled access. | Reflection: Powerful, but can bypass encapsulation and lead to unexpected behavior.
Compare the use of mutator methods in procedural vs. object-oriented programming.
Procedural: Less common, data and functions are separate. | Object-oriented: Integral part of encapsulation and object state management.
What is a mutator method?
A method that changes the values of instance variables of an object.
What is another name for mutator methods?
Setter methods.
What does 'void' mean in the context of a method?
The method does not return any value.
What is an immutable class?
A class with no mutator methods, meaning its state cannot be changed after creation.
What is the typical return type of a mutator method?
void
What is the purpose of a parameter in a mutator method?
To provide the new value to which the instance variable will be set.
What is an instance variable?
A variable defined in a class for which every object of the class has its own copy.
What is the difference between accessor and mutator methods?
Accessor methods retrieve the values of instance variables, while mutator methods modify them.
Why might a class not have a mutator method for a specific instance variable?
To prevent clients from changing the data of that instance variable, ensuring data integrity.
What is the signature of a mutator method?
Typically 'public void methodName(DataType parameterName)'
What are the general steps to write a mutator method?
- Determine the instance variable to modify. 2. Define the method signature (public void setVariableName(DataType parameterName)). 3. Implement the method body to assign the parameter value to the instance variable. 4. Add any necessary validation or error checking.
What is the process of using a mutator method to update an object's state?
- Create an instance of the class. 2. Call the mutator method on the object, passing the new value as a parameter. 3. The object's state is updated internally.
What are the steps to determine if a class should have a mutator method for a specific instance variable?
- Analyze the requirements of the class and its intended use. 2. Determine if external clients should be allowed to modify the value of the instance variable. 3. Consider the potential impact of modifications on the object's state and data integrity. 4. If modifications are necessary and safe, create a mutator method; otherwise, leave the instance variable immutable.
What are the steps involved in validating input within a mutator method?
- Receive the input parameter. 2. Check if the input meets the required criteria (e.g., data type, range, format). 3. If the input is invalid, either reject the input (throw an exception or return an error code) or sanitize the input (e.g., trim whitespace, convert to a valid format). 4. If the input is valid, assign it to the instance variable.
What is the process of deciding whether a mutator method should return a value or be void?
- Determine if the client needs to know the previous value of the instance variable. 2. If the client needs the previous value (e.g., for undo functionality), return the previous value. 3. If the client does not need the previous value, make the method void.
What are the steps to ensure thread safety when using mutator methods in a multithreaded environment?
- Identify the instance variables that are accessed and modified by multiple threads. 2. Use synchronization mechanisms (e.g., locks, mutexes) to protect access to these variables. 3. Ensure that mutator methods are atomic (i.e., they perform a single, indivisible operation). 4. Avoid race conditions and data corruption by properly synchronizing access to shared resources.
What are the steps to document a mutator method effectively?
- Write a clear and concise description of the method's purpose. 2. Specify the input parameters and their expected values. 3. Describe the effect of the method on the object's state. 4. Document any exceptions that may be thrown. 5. Provide examples of how to use the method.
What are the steps to test a mutator method thoroughly?
- Create test cases that cover different input values, including valid, invalid, and boundary values. 2. Verify that the object's state is updated correctly after calling the mutator method. 3. Check that any validation logic is working as expected. 4. Test the method in different scenarios, such as with null or empty inputs.
What are the steps to refactor a class to add or modify mutator methods?
- Analyze the existing code and identify the instance variables that need to be modified. 2. Create or modify the mutator methods to provide the necessary functionality. 3. Update any code that uses the class to use the new or modified mutator methods. 4. Test the changes thoroughly to ensure that they do not introduce any regressions.
What are the steps to handle exceptions within a mutator method?
- Identify the potential exceptions that may be thrown (e.g., IllegalArgumentException, NullPointerException). 2. Use try-catch blocks to handle the exceptions. 3. In the catch block, either log the exception, re-throw the exception, or take corrective action (e.g., set the instance variable to a default value). 4. Ensure that the exception handling logic does not introduce any new issues.