Java tutorial
//package com.java2s; public class Main { /** * checks if a condition is true * * @param condition value of the condition attribute * @return result of the evaluation of the condition */ public static boolean checkCondition(String condition) { if ((condition == null) || condition.trim().equals("")) { return true; } String value = condition.trim(); if (value.charAt(0) == '!') { return System.getProperty(value.substring(1)) == null; } return System.getProperty(value) != null; } }