Simplifying Method Calls
These techniques make method calls simpler and easier to understand. This, in turn, simplifies the interfaces for interaction between classes.
- Rename Method
Problem: The name of a method does not explain what the method does.
Solution: Rename the method.
- Add Parameter
Problem: A method does not have enough data to perform certain actions.
Solution: Create a new parameter to pass the necessary data.
- Remove Parameter
Problem: A parameter is not used in the body of a method.
Solution: Remove the unused parameter.
- Separate Query from Modifier
Problem: Do you have a method that returns a value but also changes something inside an object?
Solution: Split the method into two separate methods. As you would expect, one of them should return the value and the other one modifies the object.
- Parameterize Method
Problem: Multiple methods perform similar actions that are different only in their internal values, numbers or operations.
Solution: Combine these methods by using a parameter that will pass the necessary special value.
- Replace Parameter with Explicit Methods
Problem: A method is split into parts, each of which is run depending on the value of a parameter.
Solution: Extract the individual parts of the method into their own methods and call them instead of the original method.
- Preserve Whole Object
Problem: You get several values from an object and then pass them as parameters to a method.
Solution: Instead, try passing the whole object.
- Replace Parameter with Method Call
Problem: Calling a query method and passing its results as the parameters of another method, while that method could call the query directly.
Solution: Instead of passing the value through a parameter, try placing a query call inside the method body.
- Introduce Parameter Object
Problem: Your methods contain a repeating group of parameters.
Solution: Replace these parameters with an object.
- Remove Setting Method
Problem: The value of a field should be set only when it is created, and not change at any time after that.
Solution: So remove methods that set the field's value.
- Hide Method
Problem: A method is not used by other classes or is used only inside its own class hierarchy.
Solution: Make the method private or protected.
- Replace Constructor with Factory Method
Problem: You have a complex constructor that does something more than just setting parameter values in object fields.
Solution: Create a factory method and use it to replace constructor calls.
- Replace Error Code with Exception
Problem: A method returns a special value that indicates an error?
Solution: Throw an exception instead.
- Replace Exception with Test
Problem: You throw an exception in a place where a simple test would do the job?
Solution: Replace the exception with a condition test.