Description: The isEmpty function returns true if the Subject is null, does not contain any characters or contains only white-space (new line, carriage return, space, tab), false otherwise.

Subject Type: String

Arguments: No arguments

Return Type: Boolean

Examples: ${filename:isEmpty()} returns true if the "filename" attribute does not exist or contains only white space. ${literal(""):isEmpty()} returns true as well as ${literal(""):isEmpty()}.