Simplifying Method Calls.

Problem: A method doesn’t have enough data to perform certain actions. Solution: Create a new parameter to pass the necessary data.

Problem: A method isn’t used by other classes or is used only inside its own class hierarchy. Solution: Make the method private or protected.

Problem: Your methods contain a repeating group of parameters. Solution: Replace these parameters with an object.

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.

Problem: You get several values from an object and then pass them as parameters to a method. Solution: Instead, try passing the whole object.

Problem: A parameter isn’t used in the body of a method. Solution: Remove the unused parameter.

Problem: The value of a field should be set only when it’s created, and not change at any time after that. Solution: So remove methods that set the field’s value.

Problem: The name of a method doesn’t explain what the method does. Solution: Rename the 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.

Problem: A method returns a special value that indicates an error? Solution: Throw an exception instead.

Problem: You throw an exception in a place where a simple test would do the job? Solution: Replace the exception with a condition test.

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.

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.

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.