guarded pattern

Change-Id: Ie19a4c135c6429a60d41807f151779ce76eedbfe
Signed-off-by: Kalyan Prasad Tatavarthi <kalyan_prasad@in.ibm.com>
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.core/+/184147
Reviewed-by: Jay Arthanareeswaran <jarthana@in.ibm.com>
Tested-by: JDT Bot <jdt-bot@eclipse.org>