#881 – When to Throw Exceptions

Your code should throw an exception when

• Something has gone wrong and your code cannot execute normally
• You catch an exception and want to add some additional information
• You catch an exception and your application cannot gracefully recover from the problem

Some examples of when you might throw an exception:

• Parameter value that is out of range passed to a function
• Parameter values that are inconsistent passed to a function
• Invalid values passed to function (e.g. username with wrong password)
• Function called while application is in the wrong state 

Do not throw exceptions

• As part of normal operation, to control program flow
• To return data back to code that called a function
• Just to indicate which function was executing when an exception was caught