Here you can find the source of checkIpMaskPart(String part)
private static String checkIpMaskPart(String part)
//package com.java2s; //License from project: Open Source License public class Main { private static String checkIpMaskPart(String part) { int dash; if ("*".equals(part)) return null; dash = part.indexOf('-'); if (dash == -1) { int value = Integer.parseInt(part); if (value < 0 || value > 255) return (new StringBuilder()).append("Value out of range in '").append(part).append("'").toString(); //break MISSING_BLOCK_LABEL_219; }/*from w w w. j ava2 s .c o m*/ int from; from = Integer.parseInt(part.substring(0, dash)); if (from < 0 || from > 255) return (new StringBuilder()).append("'From' value out of range in '").append(part).append("'") .toString(); int to; try { to = Integer.parseInt(part.substring(dash + 1)); if (to < 0 || to > 255) return (new StringBuilder()).append("'To' value out of range in '").append(part).append("'") .toString(); } catch (NumberFormatException e) { return (new StringBuilder()).append("Integer parsing error in '").append(part).append("'").toString(); } if (from > to) return (new StringBuilder()).append("'From' value is greater than 'To' value in '").append(part) .append("'").toString(); return null; } }