Matches regular expressions in the haystack. Any matched strings are returned in a list.

Regex.java

package util;

import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Regex {

	/**
	 * Matches regular expressions in the haystack. Any matched strings are
	 * returned in a list.
	 * 
	 * @param regex
	 *            The regular expression with which to match
	 * @param haystack
	 *            The string from which to find matches
	 * @return A {@link List} of {@link String} objects where every String
	 *         matches the regex and they are all in the haystack
	 */
	public static List<String> getMatches(String regex, String haystack) {

		if (regex == null || regex.equals("")) {
			throw new IllegalArgumentException("regex cannot be null or empty.");
		}

		if (haystack == null || haystack.equals("")) {
			throw new IllegalArgumentException("haystack cannot be null or empty.");
		}

		List<String> result = new LinkedList<String>();

		Pattern pattern = Pattern.compile(regex);
		Matcher matcher = pattern.matcher(haystack);

		while (matcher.find()) {
			result.add(haystack.substring(matcher.start(), matcher.end()));
		}

		return result;

	}
}