Regexp to match a command line java application execution with args

Question

I'm absolutely not familiar with regexes so better to ask then do something very silly. I have a java application that is to be executed from command line, and it has a pretty nice signature.

java applicationName -mode=create -some.nice.arg=XXX.XXX.XXX.XXX:XXXX -another.nice.arg=value2 -third.nice.arg=value3 -again.nice.arg=value4 ... -nth.nice.arg=value_n+1

This would be the desired format. Well at least close enough. I'm trying to create a regexp that matches this and would select the argument fields like:

mode=create
some.nice.arg=XXX.XXX.XXX.XXX:XXXX
another.nice.arg=value2
third.nice.arg=value3
again.nice.arg=value4
...
nth.nice.arg=value_n+1

I have no problem creating a regexp for IP address for example, but I can't create one that would match this whole stuff. So far my best bet was:

\w+[ ]{1}\w+[ ]{1}[-]{1}(\w+[=]{1}\w+){+}

Lots of problems. For example \w+ won't match '.' chars but they will be there for sure. Or for another example: mode can have one of the following options:

create
update
clear

I'm kinda shot even at the first problem not to mention the second.

Thanks for every help! - Joey

Duncan Jones · Accepted Answer · 2013-05-16 11:12:56Z

2

The correct way to solve this problem is to use a command line interface library, such as Commons CLI. Using these libraries you can define the arguments for your application and the library will validate the input (i.e. your String[] args) against this.

Most CLI libraries can handle advanced concepts such as optional arguments, flags, multi-part arguments etc. They can also be used to print a helpful usage message for your users. Check out some examples here.

Once you've used a library such as this to gather the arguments, you can then use a regexp (if necessary) to validate each part separately.

edited May 16, 2013 at 11:12

answered May 16, 2013 at 11:07

Duncan Jones

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1 Comment

Wrath Over a year ago

Awesome solution. thanks for recommending this Commons CLI. works like a charm.

AlexR · Accepted Answer · 2013-05-16 11:11:40Z

1

If you really want to create regex for this here is the tip:

mode=(\\w+)\\s+some.nice.arg=((?:\\w{3}\\.){3}\\w{3}:\\w{4})\\s+another.nice.arg=(\\S+?)\\s+third.nice.arg=(\\S+?)\\s+again.nice.arg=(\\S+?)

etc, etc.

However better way is to split you line into segments and then process each one:

String line = ....;
String[] segments = line.split("\\s+");

for (String segment : segments) {
    String[] parts = segment.split("=");
    String name = parts[0];
    String value = name[1];
    // deal with names and values
}

answered May 16, 2013 at 11:11

AlexR

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Comments

sp00m · Accepted Answer · 2013-05-16 12:26:12Z

0

This could suit your needs to capture the parameters:

-([a-zA-Z.-]+)=((?:"[^"]+"|[^ ])+)

Demo

edited May 16, 2013 at 12:26

answered May 16, 2013 at 12:00

sp00m

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