my @headerElements = ( 'value 1', 'value 2', 'value  3' );
@headerElements = split /\s+/, $headerStr if $headerStr;

##</code><code>##

my @headerElements = ( $headerStr
                      ? split /\s+/, $headerStr
                      : ( 'value 1', 'value 2', 'value  3' )
                      );

##</code><code>##

my @headerElements = split( /\s+/, $headerStr ) || ( 'value 1', 'value 2', 'value  3' );