Can Java String.indexOf() handle a regular expression as a parameter?

Question

I want to capture the index of a particular regular expression in a Java String. That String may be enclosed with single quote or double quotes (sometimes no quotes). How can I capture that index using Java?

eg:

capture String -->  class = ('|"|)word('|"|)

Answer 1

No.

Check source code for verification

WorkAround : Its not standard practice but you can get result using this.

Update:

    CharSequence inputStr = "abcabcab283c";
    String patternStr = "[1-9]{3}";
    Pattern pattern = Pattern.compile(patternStr);
    Matcher matcher = pattern.matcher(inputStr);
    if(matcher.find()){

    System.out.println(matcher.start());//this will give you index
    }

OR

Regex r = new Regex("YOURREGEX");

// search for a match within a string
r.search("YOUR STRING YOUR STRING");

if(r.didMatch()){
// Prints "true" -- r.didMatch() is a boolean function
// that tells us whether the last search was successful
// in finding a pattern.
// r.left() returns left String , string before the matched pattern 
int index = r.left().length();
} 

Answer 2

It's a two-step approach. First, find a match for your pattern, then (second) use Matcher#start to get the position of the matching String in the content String.

Pattern p = Pattern.compile(myMagicPattern);  // insert your pattern here
Matcher m = p.matcher(contentString);
if (m.find()) {
   int position = m.start();
}

Answer 3

Based on @Andreas Dolk's answer, wrapped in copy and paste ready code:

/**
 * Index of using regex
 */
public static int indexOfByRegex(CharSequence regex, CharSequence text) {
    return indexOfByRegex(Pattern.compile(regex.toString()), text);
}

/**
 * Index of using regex
 */
public static int indexOfByRegex(Pattern pattern, CharSequence text) {
    Matcher m = indexOfByRegexToMatcher(pattern, text);
    if ( m != null ) {
        return m.start(); 
    }
    return -1;
}

/**
 * Index of using regex
 */
public static Matcher indexOfByRegexToMatcher(CharSequence regex, CharSequence text) {
    return indexOfByRegexToMatcher(Pattern.compile(regex.toString()), text);
}

/**
 * Index of using regex
 */
public static Matcher indexOfByRegexToMatcher(Pattern pattern, CharSequence text) {
    Matcher m = pattern.matcher(text);
    if ( m.find() ) {
        return m;
    }
    return null;
}