Check if the line contains /*

Question

I want to check if my line contains /* or not. I know how to check if the block comment is in the start:

/* comment starts from the beginning and ends at the end */

if(line.startsWith("/*") && line.endsWith("*/")){

      System.out.println("comment : "+line);  
}

What I want to know is how to figure the comment is, like this:

something here /* comment*/

or

something here /*comment */ something here

@sureshatta. There is a question. Just that it doesn't end in a `?`. — Rohit Jain, Aug 03 '13 at 20:50
@sureshatta *What I want to know is how to figure the comment is like, this* it needs a `?` at the end, but it is a question. — Luiggi Mendoza, Aug 03 '13 at 20:50
"What I want to know is how to figure the comment is like, this : " is my question — gecco, Aug 03 '13 at 20:51
I have used StringTokenizer. But it gets complicated. I am looking if there is another less complicated way to do it. — gecco, Aug 03 '13 at 20:53
take a look to [Pattern](http://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html) — nachokk, Aug 03 '13 at 20:54
Use `Pattern` and `Matcher` classes and use a regexp like this: `/\\*.*\\*/`. — Luiggi Mendoza, Aug 03 '13 at 20:55
You're welcome. By the way, you shoud use `@` (no spaces) to send an answer in comments to other user. — Luiggi Mendoza, Aug 03 '13 at 21:01

Ravi K Thapliyal · Answer 1 · 2013-08-03T21:25:15.283

This works for both // single and multi-line /* comments */.

Pattern pattern = Pattern.compile("//.*|/\\*((.|\\n)(?!=*/))+\\*/");
String code = " new SomeCode(); // comment \n" + " " + "/* multi\n"
        + " line \n" + " comment */\n"
        + "void function someFunction() { /* some code */ }";
Matcher matcher = pattern.matcher(code);
while (matcher.find()) {
    System.out.println(matcher.group());
}

Output:

// comment 
/* multi
 line 
 comment */
/* some code */

Ankur Shanbhag · Accepted Answer · 2013-08-03T21:04:28.073

1

Try using this pattern :

String data = "this is amazing /* comment */ more data ";
    Pattern pattern = Pattern.compile("/\\*.*?\\*/");

    Matcher matcher = pattern.matcher(data);
    while (matcher.find()) {
        // Indicates match is found. Do further processing
        System.out.println(matcher.group());
    }

edited Aug 03 '13 at 21:04

answered Aug 03 '13 at 20:57

Ankur Shanbhag

7,746
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Comments `/* looks like this */` while your pattern doesn't. – Luiggi Mendoza Aug 03 '13 at 21:00
Thanks for pointing it out. I have made appropriate changes in the code. Please verify, it should work now. – Ankur Shanbhag Aug 03 '13 at 21:05
what is the package I should use to get Matcher? – gecco Aug 03 '13 at 21:13
Matcher and Pattern class are available in java.util.regex package. – Ankur Shanbhag Aug 03 '13 at 21:15

score 0 · Answer 3 · answered Aug 03 '13 at 20:55

0

You can to this multiple ways, here is one:

Find the "/*" in your String:

int begin = yourstring.indexOf("/*");

do the same for "*/"

This will get you two Integers with which you can get the substring containing the comment:

String comment = yourstring.substring(begin, end);

answered Aug 03 '13 at 20:55

Delpes

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What if I have `a */ string /* like this`? – Luiggi Mendoza Aug 03 '13 at 20:56
you invert begin an end? I am supposing you are imposing the syntax on how the comment will look like – Delpes Aug 03 '13 at 20:59

Check if the line contains /*

3 Answers3