Reg: Null values in context

Hi,

I have a context node and 3 context attributes. I am binding this context attributes to 3 input fields.

I also have a search functionality which takes the 3 input field parameters as inputs and the input fields are not mandatory. But when i have no value in any of the input fields, it is giving me null pointer exception as i am passing one of the attribute as null to search functionality. How can i avoid this.

Please suggest.

Thanks.