CODEWITHSUNDEEP
javaregex
mohan
mohan

Reputation: 87

How to replace particular substring using regular expression using java

I have a string as below 

   when 
   $Event:com.abc.Event(description == "abc")
   then
   logger.info("description");

I need to replace the above string with below

   when
   $Event:com.abc.Event(description == "abc") from entry-point "EventStream"
   then
   logger.info("description");

In the same way when i encounter 

when
$Alarm:com.abc.Alarm(description == "abc")
then
logger.info("alarm description");

i need to change as below

when
$Alarm:com.abc.Alarm(description == "abc") from entry-point "AlarmStream"
then
logger.info("alarm description");

i would like to replace the string using regular expression using greedy match. Please provide me some pointers to acheive the same.

Upvotes: 0

Views: 160

Answers (2)

user425367
user425367

Reputation:

New answer that will use a regex and a test class.

import java.util.Scanner;


public class RegEx {

public static void main(String[] args) {
    String text = "when\n$Alarm:com.abc.Alarm(description == \"abc\")\nthen\nlogger.info(\"alarm description\")";
    System.out.println(text);
    StringBuilder sb = new StringBuilder();
    Scanner scan = new Scanner(text);
    while(scan.hasNextLine()){
        String line = scan.nextLine();
        if(line.matches(".*\\.Alarm(.*).*")){
            line+=" from entry-point \"AlarmStream\"";
        }
        sb.append(line+System.getProperty("line.separator"));
    }
    System.out.println(); // Nicer output
    System.out.println(sb.toString());
}

}

The output

when

$Alarm:com.abc.Alarm(description == "abc")

then

logger.info("alarm description")

when

$Alarm:com.abc.Alarm(description == "abc")from entry-point "AlarmStream"

then

logger.info("alarm description")

Upvotes: 0

user425367
user425367

Reputation:

Easy solution don't bother with regex use Strings method contains instead. Make a Scanner object that parses your string line for line and add the result to a String buffer.

if(line.contains("$Event:com.abc.Event(description == "abc")"){
  sb.append(line + "from entry-point \"EventStream\" ");
} else if(line.contains("$Alarm:com.abc.Alarm(description == \"abc\")") {
 sb.append(line + "from entry-point \"AlarmStream\" ");
}else {
 sb.append(line);
}

Upvotes: 1

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