Salesforce Apex Query with Wildcard

query.cls

public static String getAllQuery(String query) {
	String result = '';

	String regex = '^select\\s+\\*\\s*(?:,\\s*[^\\s]+\\s*)*\\s+from\\s+([^\\s]+)(.*)$';
	Matcher m = Pattern.compile(regex).matcher(query.toLowerCase());
	if(m.matches()) {
		String sObjectName = m.group(1);
		Schema.SObjectType targetType = Schema.getGlobalDescribe().get(sObjectName);
		Map<String, Schema.SObjectField> fieldMap = targetType.getDescribe().fields.getMap();

		List<String> fieldList = new List<String>();
		fieldList.addAll(fieldMap.keyset());
		String allFields = String.join(fieldList, ', ');
		System.debug('Have field list: ' + allFields);

		result = query.replace('*', allFields);
	} 
	else {
		result = query;
	}
	return result;
}