src/org/tiefaces/components/websheet/utility/WebSheetUtility.java
public static String getSheetNameFromFullCellRefName(
			final String fullName) {
		if ((fullName != null) && (fullName.contains("!"))) {
			return fullName.substring(0, fullName.indexOf('!'));
		}
		return null;
	}
public static String getSheetNameFromFullCellRefName(
			final String fullName) {
		if ((fullName != null) && (fullName.contains("!"))) {
			return fullName.substring(0, fullName.indexOf('!'));
		}
		return null;
	}
return sheet name from cell full name e.g. return Sheet1 from Sheet1$A$1

@param fullName
the full name
@return String Sheet Name