code: private String wrappedMapping(boolean makeDest,NullPointerControl npc,MappingType mtd,MappingType mts){	
  		String sClass = source.getName();
  		String dClass = destination.getName();
  		
  		String str = (makeDest?"   "+sClass+" "+stringOfGetSource     +" = ("+sClass+") $1;"
  				              :"   "+dClass+" "+stringOfGetDestination+" = ("+dClass+") $1;"+newLine+
  				               "   "+sClass+" "+stringOfGetSource     +" = ("+sClass+") $2;")+newLine;
  
  		switch(npc){
  		  case SOURCE: 	    str +="if("+stringOfGetSource+"!=null){"     +newLine; break;
  		  case DESTINATION: str +="if("+stringOfGetDestination+"!=null){"+newLine; break;
  		  case ALL:	        str +="if("+stringOfGetSource+"!=null && "+stringOfGetDestination+"!=null){"+newLine;break;
  		  default: break;
  		}
  
  		str +=     mapping(makeDest,mtd,mts)          + newLine
  			+  "   return "+stringOfSetDestination+";"+ newLine;
  
  		return (npc != NOT_ANY) ? str +=  "}"             + newLine
  				                      +   " return null;" + newLine
  				                : str;
  	}
docs: This method adds the Null Pointer Control to mapping created by the mapping method.
  wrapMapping is used to wrap the mapping returned by mapping method.
  
  @param makeDest true if destination is a new instance, false otherwise
  @param npc a NullPointerControl chosen
  @param mtd Mapping Type of destination
  @param mts Mapping Type of source
  @return a String that contains the mapping
  @see MapperConstructor#write
  @see NullPointerControl
  @see MappingType