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I'm trying to match a string with Pattern/Matcher. I want to extract sub string from a string. could anybody give me the solution to match the following sub string?

<!-- if(Rajendra Patel == 'Rajendra Patel'){
---
<br />
User Name : Rajendra Patel
<br />
Organization Name : VersatileCapitalist Software Inc
<br />
Date : 27/01/2015
<br />
Time : 5:15 PM
<br />
Date Time : 27/01/2015 5:15 PM
<br />
Year : 2015
<br />
Month : 1
<br />
Next Day(Tomorrow): 28/01/2015
<br />
LastDay(Yesterday) : 26/01/2015
<br />
} -->

The following regular expressions is working fine in javascript and java but it is not working in apex. working in javascript: <!([-]*)(\s+)(If|if)(?:\n|.)*\}\s--> Not working in apex: <!([-]*)(\\s+)(If|if)(?:\\n|.)*\\}\\s-->

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  • This would get better answers if you explained what you wanted to actually match.
    – Charles Koppelman
    Commented Jan 27, 2015 at 16:21

1 Answer 1

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The APEX compiler works very different for RegEx than what you're used to with JS. First, none of the Global Switches are supported. Some things need to have additional escapes and pretty much everything needs to be in capture groups. That's because Apex uses different methods of it's own in the matcher class to provide this kind of functionality.

I believe you'll find that your (If|if) needs to be replaced with an ((If)|(if)).

With the way Apex works, you'll probably want to remove what appears to be a non-capture group: (?:\n|.)

To get you to the start of the name, I'd expect your pattern to look something more like the following:

(((<!)(\-*)(\\s*)((If)|(if)))\()

I recommend you go to http://regexr.com/ , paste in the string <!-- if(Rajendra Patel == 'Rajendra Patel'){ assuming that's what you want to match against, in the text box below (after clearing it), then work out the pattern for yourself.

I'd also suggest you think in terms of combining RegEX with other string methods to strip away things that are easy to find that you know you don't need or want. This will make your task easier.

For example, once you find your opening and closing parens inside the lesser and greater than symbols, you can strip away what's outside of them. You could also split the string based on finding the ==. Be smart and don't make this more complex than it has to be.

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  • Can you elaborate on what you mean by "none of the Global Switches are supported"? What switches/behavior are you referring to?
    – Mark Pond
    Commented Jun 17, 2015 at 16:43
  • I used the wrong terminology. I was referring to "flags" like /g (global). /m (multiline) and /i (ignore case). I've never been able to use any of them in my code.
    – crmprogdev
    Commented Jun 17, 2015 at 16:51
  • You can use embedded flag expressions at the beginning of the pattern to set those options. Case insensitive: (?i); Multiline: (?m); Dotall: (?s); Unicode: (?u). No solution for the array of matches that come from the /g in JavaScript though, here we've got to iterate the matches and build it manually.
    – Mark Pond
    Commented Jun 17, 2015 at 17:14
  • 1
    Thanks, Mark! That explains why I could never get them to work with apex! Am always learning new tidbits and nuances here that aren't documented anyplace in the SF docs. I don't know how you managed to find that in the Oracle docs!! I'm impressed! And all this from editing the tags on an old post. :)
    – crmprogdev
    Commented Jun 17, 2015 at 17:26

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