src/main/java/com/github/mjeanroy/springmvc/view/mustache/commons/PreConditions.java
public static String hasText(String value, String message) {
		if (value == null) {
			throw new IllegalArgumentException(message);
		}

		for (char c : value.toCharArray()) {
			if (!Character.isWhitespace(c)) {
				return value;
			}
		}

		// Found only whitespace characters...
		throw new IllegalArgumentException(message);
	}
public static String hasText(String value, String message) {
		if (value == null) {
			throw new IllegalArgumentException(message);
		}

		for (char c : value.toCharArray()) {
			if (!Character.isWhitespace(c)) {
				return value;
			}
		}

		// Found only whitespace characters...
		throw new IllegalArgumentException(message);
	}
Check that a given string value is not blank (i.e. not null,
not empty and does not contain only whitespaces).
If value is blank, an {@link java.lang.IllegalArgumentException} is
thrown.
If value is not blank, original string value is automatically returned.

@param value String value.
@param message Error message given to exception.
@return Original string value.
@throws java.lang.IllegalArgumentException if value is blank.