Java Regex - Conditional Grouping

Question

I need to parse the following lines in 2 groups:
Group 1: ADJ-1-37-10
Group 2: 3.00 (if there's no SPANLOSSMARGIN tag then it should be empty)

So far I used "(ADJ-\d{1,3}-\d{1,3}-\d{1,3})::.*?SPANLOSSMARGIN=(\d{1,2}.\d{1,2}) to parse the following lines. But it's not matching the ADJ-1-37-16 as the line doesn't contain the SPANLOSSMARGIN tag. My requirement is when there's ADJ-X-XX-XX tag (irrespective of the presence of other tags) then Group 1 should return it and when there's is SPANLOSSMARGIN tag then Group 2 should return it; but only when there's no SPANLOSSMARGIN tag, Group 2 should return empty. How can I achieve this?

"ADJ-1-2-5::FIBERTYPE=NDSF,OSCSPANLOSS=16.00,TARGSPANLOSS=16.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00"
   "ADJ-1-13-5::FIBERTYPE=NDSF,OSCSPANLOSS=16.00,TARGSPANLOSS=16.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00"
;
   "ADJ-1-37-2::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-4::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-8::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-10::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-14::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-16::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-20::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""
   "ADJ-1-37-22::FIBERTYPE=UNKNOWN,TARGSPANLOSS=0.00,MINSPANLOSS=0.00,SPANLOSSMARGIN=3.00,SPANLOSSSOURCE=UNKNOWN,BUNDLEID=\"\",LINEIN=\"\",LINEOUT=\"\",CRSIN=\"\",CRSOUT=\"\""

Stephan · Accepted Answer · 2015-09-08 10:39:34Z

1

Try this:

(ADJ-\d{1,3}-\d{1,3}-\d{1,3})::(.(SPANLOSSMARGIN=)?(\d{1,2}.\d{1,2})?)*

You can try it here:

http://fiddle.re/qm6j86

Group 4 is the match for SPANLOSSMARGIN= , if SPANLOSSMARGIN= doesn't exists than group 3 will be null

answered Sep 8, 2015 at 10:39

Stephan

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4 Comments

surz Over a year ago

I had to modify this to (ADJ-\d{1,3}-\d{1,3}-\d{1,3})::(.(SPANLOSSMARGIN=(\d{1,2}.\d{1,2}))?)* as Group 4 was returning 0.00 even if there's no SPANLOSSMARGIN tag. Is it OK?

Stephan Over a year ago

@surz i said in my answer you need to check group 3 to see if a match was made

surz Over a year ago

you are right, I'm directly using Group 4, so had to tweak a little bit, do you see any issue in this regex?

Stephan Over a year ago

the one that you modified seems fine to me

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