[SalesForce] Regular Expression is not working in apex

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-->

Best Answer

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.

Related Solutions

[SalesForce] Using RegEx Pattern Match to create DateTime fields in trigger

Ultimately, the code I came up with for validation looked something like what's below:

list<Event> ToInsert = new list<Event>();
Date ClosDt;
Integer ClsDay; 
Integer ClsMnth;
Integer ClsYear; 
String sClsDay; 
String sClsMnth;
String sClsYear; 
String StrtTmDt;
Integer plnMns;
String endTm;
String endDtTm;
String notes;
Pattern TimePttrn = Pattern.compile('((([1])([0-2])|(([0])([1-9])))(\\u003A)(([0-5])([0-9]))(\\s)(([AP])([M])))'); // hh:mm a


// The initial section below is to use Event_Notes__c to track any error messages 
// related to the start time and return them for correction while allowing 
// successful creation of the event. It existed before we went to a picklist.

try{
    If (opp.Event_Notes__c == null) notes = 'None';

    }catch(NullPointerException e){

    notes = 'None';

    } 

    notes = opp.Event_Notes__c;

try{
    opp.Event_Start_Time_Pik__c.normalizeSpace();

    }catch(NullPointerException e){

        if (notes == 'None') {

            notes = 'Error A1 processing Start Time!!! Check for correct time and resubmit form.';

            opp.Event_Start_Time_Pik__c = '12:00 AM';

        } else{

            notes = 'Error A2 processing Start Time!!! Check for correct time and resubmit form.'+ notes;

            opp.Event_Start_Time_Pik__c = '12:00 AM'; 

        }

    } // End try/catch block

// Do time pattern and match validation

Matcher m = TimePttrn.matcher(opp.Event_Start_Time_Pik__c);
boolean hasMatch = m.matches();
strtTm = m.group(0);

opp.Event_Notes__c = notes;

// Assemble StartTimeDate and Calculate Planned Mins

ClosDt = opp.CloseDate;
ClsDay = ClosDt.day();

if(ClsDay >= 1 && ClsDay <= 9){ 

sClsDay = '0' + String.ValueOf(ClsDay);

} else {

sClsDay = String.ValueOf(ClsDay);

}

ClsMnth = ClosDt.month();

if(ClsMnth >=0 && ClsMnth <= 9){ 

   sClsMnth = '0' + String.ValueOf(ClsMnth);

   } else {

   sClsMnth = String.ValueOf(ClsMnth);

   }

ClsYear = ClosDt.year();

sClsYear = String.ValueOf(ClsYear);    

StrtTmDt = sClsMnth + '/' + sClsDay + '/' + sClsYear + ' ' + strtTm;

Later in the code when creating the event:

Event e = New Event(StartDateTime = DateTime.parse(StrtTmDt), ActivityDateTime = DateTime.parse(StrtTmDt), EndDateTime = (DateTime.parse(StrtTmDt)).addMinutes(plnMns), DurationInMinutes = plnMns, Subject = EvtSubjct, OwnerId = opp.Owner.Id, WhatId = opp.Id, WhoId = opp.Customer_Contact__r.Id, Description = Descr1 + Descr2 + Descr3 + Descr5 + Descr6 + Descr7 );

I wound up doing a lot of string method and regex testing bits of code in the Developer Console and creating some string test classes before I managed to get all of this to work satisfactorily. I learned a great deal in the process. I hope others find this of use as until there's a "true" Time method other than the Salesforce System Time, this will continue to be an issue we'll all need to deal with on occasion.

[SalesForce] Issues with Regex matcher on APEX

There's two issues here: one is escaping the regex correctly, and one is the semantics of checking for a match. The following code works:

Pattern regex = Pattern.compile('(?m)([A-Z]{2,3})[\\s]+([0-9]+[\\-/.][0-9][0-9][\\-/.][0-9]+)[\\s:,-]+([^\\n]+)$');
Matcher regexMatcher = regex.matcher(message);

while (regexMatcher.find()) {
    System.debug(regexMatcher.group());
}

09:43:06:004 USER_DEBUG [14]|DEBUG|AA 22/05/2017: First block of text.

09:43:06:004 USER_DEBUG [14]|DEBUG|BB 15/05/2017: Second block of text.

09:43:06:004 USER_DEBUG [14]|DEBUG|AA 01/05/2017: Third block of text

Note that Matcher.matches() returns true for a whole-region (whole-string, in this case) match, which we don't have. find() returns true when we're able to match, which we are here.

Additionally, you must escape all backslashes in an Apex string, and there's no need to escape a forward slash or period in a regex character class.

Best Answer

Related Solutions

[SalesForce] Using RegEx Pattern Match to create DateTime fields in trigger

[SalesForce] Issues with Regex matcher on APEX

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