Connect and share knowledge within a single location that is structured and easy to search. Why does my check up on the Boolean variable "bool" result in an exception? Shouldn't it just jump right past the if statement when it "sees" that it isn't true? When I remove the if statement or check up on if it's NOT null, the exception goes away. When you have a boolean it can be either true or false. Yet when you have a Boolean it can be either Boolean. TRUE , Boolean. FALSE or null as any other object.
In your particular case, your Boolean is null and the if statement triggers an implicit conversion to boolean that produces the NullPointerException. You may need instead:. Use the Apache BooleanUtils. If peak performance is the most important priority in your project then look at one of the other answers for a native solution that doesn't require including an external library.
Checks if a Boolean value is true, handling null by returning false. If you're not limited to the libraries you're "allowed" to include, there are a bunch of great helper functions for all sorts of use-cases, including Booleans and Strings.
I suggest you peruse the various Apache libraries and see what they already offer. Boolean types can be null. You need to do a null check as you have set it to null. Boolean is the object wrapper class for the primitive boolean. This class, as any class, can indeed be null. For performance and memory reasons it is always best to use the primitive. There is nothing wrong with the accepted answer by K-ballo. The risk of a NullPointerException like the one you saw is too great. For example.
You may even name it NULL if appropriate. Any nullable value type is an instance of the generic System. You typically use a nullable value type when you need to represent the undefined value of an underlying value type.
For example, a Boolean, or bool , variable can only be either true or false. However, in some applications a variable value can be undefined or missing. For example, a database field may contain true or false , or it may contain no value at all, that is, NULL. You can use the bool? As a value type is implicitly convertible to the corresponding nullable value type, you can assign a value to a variable of a nullable value type as you would do that for its underlying value type.
You can also assign the null value. For example:. HasValue property returns false. Beginning with C 7. You always can use the following read-only properties to examine and get a value of a nullable value type variable:.
HasValue indicates whether an instance of a nullable value type has a value of its underlying type. Value gets the value of an underlying type if HasValue is true. The following example uses the HasValue property to test whether the variable contains a value before displaying it:. You can also compare a variable of a nullable value type with null instead of using the HasValue property, as the following example shows:.
When I flip to the Sheet 1, as indicated as a possible solution by the posters above, I can "Describe" the field and see the boolean values:. However, when I drag the field into the view, it still displays nulls:. I am using Tableau Thanks in advance to anyone willing to look into this very annoying issue!
Peter Hill. Regrettably, the issue hasn't been fixed in I encourage Tableau to fix this. The user shouldn't be required to export an Excel data source to csv to deal with a type conversion issue.
Make your field a string, by clicking on Boolean and switching to String. Create a Calculated Field that can handle your type conversion. What's happening is called "Type Coercion. I think that their reasoning would be that there are too many types of True and False, so they handle what they consider the basics! Apache Log4j2 vulnerability Log4shell Update Tableau customers, thank you for your patience as we address the Apache Log4j2 vulnerability.
View This Post. October 27, at PM. Good afternoon all, I'm importing an Excel file into Tableau and have two columns which are boolean. Cheers Mateusz. Boolean which is a non-nullable value type. From what I understand IsCoin is nullable bool bool? The content you requested has been removed. Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:.
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