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114

answers:

2

I'm converting some C# code to Java and I need to include an exception that is similar to C#'s InvalidOperationException. Does such a thing exist? Also is there a list of equivalent exception types in the two languages? Thanks.


I think in my particular case IllegalStateException is most appropriate. Thanks for all the responses.

+7  A: 

Probably IllegalStateException.

From what I read about InvalidOperationException: "The exception that is thrown when a method call is invalid for the object's current state."

For IllegalStateException: "Signals that a method has been invoked at an illegal or inappropriate time. In other words, the Java environment or Java application is not in an appropriate state for the requested operation."

Depending on how you are using InvalidOperationException, I could also see IllegalArgumentException and UnsupportedOperationException being what you want. The former implies that, in general, the method is fine to call, it was just passed garbage this time; the latter implies that the method is never appropriate to call for this instance (unlike IllegalStateException, which implies that it might be appropriate to call the subject method sometimes, just not at the moment).


I am not aware of a general c# <=> Java translation of exceptions.

Carl
+1 That's pretty much a direct match. (The .Net exception's name isn't very good, is it?)
T.J. Crowder
@T.J.: I kind of like the .Net name, especially if it were paired with the `UnsupportedOperationException` naming. I think those two names could be used to communicate the sometimes vs always distinction between the two. The .Net equivalent of an `UnsupportedOperationException` (I point it out in my comment on your answer) is *okay* name-wise (`NotSupportedException`), but both languages made crappy pairings of the two types, IMO.
Carl
+1 An illegal state causes an invalid operation. Quite logical:)
Petar Minchev
A: 

Petar pointed me to this example code (from msdn)

void WriteLog()
{
    if (!this.logFile.CanWrite)
    {
        throw new System.InvalidOperationException("Logfile cannot be read-only");
    }
    // Else write data to the log and return.
}

So in this context you could use an IllegalStateException, although it says:

Thrown when an action is attempted at a time when the virtual machine is not in the correct state.

And an illegal VM state is definitly not the issue in the above reference example. Here, the problem is that the object is invalid, because it references a read-only logfile.

My own advice: just define a custom exception like

package com.pany.project;
public class InvalidOperationException extends RuntimeException {

   // add constructors with call to super as needed

}

To me, that's much easier then trying to find the best fitting Exception from the java.lang package.

Andreas_D