Custom string utilities.

StringUtils.java

/**
* Meant to contain the custom utilities related to string. Could be handy in common use cases.
**/
public class StringUtils{

	/**
	 * Searches the given pattern in the given src string and applies the txr to
	 * the matches.
	 * <br/>
	 * <b>Note:</b> Ex, To convert snake case to camel case make the call,
	 * <br/>
	 * <i>findAndApply("some_snake_case", "_[a-z]",(x) -> x.replace("_","").toUpperCase())</i>
	 * 
	 * @param src
	 *            The string to be converted
	 * @param pattern
	 *            the pattern for which the transformers to be applied.
	 * @param txr
	 *            The transformers for the mathed patterns.
	 * @return The result after applying the transformation.
	 */
	public static String findAndApply(String src, String pattern,
			Function<String, String> txr) {
		Matcher m = Pattern.compile(pattern).matcher(src);

		StringBuilder sb = new StringBuilder();
		int last = 0;

		while (m.find()) {
			sb.append(src.substring(last, m.start()));
			sb.append(txr.apply(m.group(0)));
			last = m.end();
		}
		sb.append(src.substring(last));
		return sb.toString();
	}
    
	/**
	 * Converts the map as URL encoded string.
	 * 
	 * @param map
	 *            The {@link Map} to be converted as url encoded string.
	 * @return URL encoded string.
	 */
	public static String asUrlEncodedString(Map<String, Object> map) {
		return map.entrySet().stream()
				.map(e -> e.getValue() == null
						? e.getKey()
						: e.getKey() + "=" + e.getValue().toString())
				.collect(Collectors.joining("&"));
	}
	
	public static List<String> findSubstringsMatchingPattern(String source, String pattern) {
        	return Pattern.compile(pattern).matcher(source).results().map(MatchResult::group).collect(Collectors.toList());
	}
}