regex

Line ending matching example

With this example we are going to demonstrate how to check a line ending matching. We are using Patterns and Matchers against each pattern. In short, to check a line ending matching you should:

  • Create a String array that contains the patterns to be used.
  • For every pattern in the array compile it to a Pattern, using compile(string regex) API method of Pattern.
  • Use matcher(CharSequence input) API method of Pattern to get a Matcher that will match the given input String against this pattern.
  • Use find() API method of Matcher to find the next subsequence of the input sequence that matches the pattern.
  • Then compile it to a Pattern, using compile(String regex, int flags) API method of Pattern with specified pattern modes as flags.
  • Use matcher(CharSequence input) API method of Pattern to get a matcher that will match the given input String against this pattern.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;

import java.util.regex.Pattern;

/*
** Show line ending matching using RE class.
*/

public class LineEndings {

    public static void main(String[] argv) {


  String inputStr = "I dream of enginesnmore engines, all day long";

  

  System.out.println("INPUT: " + inputStr);

  System.out.println();


  String[] pattern = {"engines.more engines", "engines$"};


  for (int i = 0; i < pattern.length; i++) {





System.out.println("PATTERN " + pattern[i]);



boolean found;





Pattern pattern1l = Pattern.compile(pattern[i]);


found = pattern1l.matcher(inputStr).find();





System.out.println("DEFAULT match " + found);



Pattern patternml = Pattern.compile(pattern[i], Pattern.DOTALL | Pattern.MULTILINE);


found = patternml.matcher(inputStr).find();





System.out.println("MultiLine match " + found);


  }
    }
}

Output:

INPUT: I dream of engines
more engines, all day long

PATTERN engines.more engines
DEFAULT match false
MultiLine match true
PATTERN engines$
DEFAULT match false
MultiLine match true

 
This was an example of how to check a line ending matching in Java.

Ilias Tsagklis

Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.
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