Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.validator.routines; import java.io.Serializable; /** * <p> * <b>InetAddress</b> validation and conversion routines (<code>java.net.InetAddress</code>). * </p> * * <p> * This class provides methods to validate a candidate IP address. * * <p> * This class is a Singleton; you can retrieve the instance via the {@link #getInstance()} method. * </p> * * @version $Revision: 594917 $ * @since Validator 1.4 */ public class InetAddressValidator implements Serializable { private static final String IPV4_REGEX = "^(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})$"; /** * Singleton instance of this class. */ private static final InetAddressValidator VALIDATOR = new InetAddressValidator(); /** IPv4 RegexValidator */ private final RegexValidator ipv4Validator = new RegexValidator(IPV4_REGEX); /** * Returns the singleton instance of this validator. * * @return the singleton instance of this validator */ public static InetAddressValidator getInstance() { return VALIDATOR; } /** * Checks if the specified string is a valid IP address. * * @param inetAddress the string to validate * @return true if the string validates as an IP address */ public boolean isValid(String inetAddress) { return isValidInet4Address(inetAddress); } /** * Validates an IPv4 address. Returns true if valid. * * @param inet4Address the IPv4 address to validate * @return true if the argument contains a valid IPv4 address */ public boolean isValidInet4Address(String inet4Address) { // verify that address conforms to generic IPv4 format String[] groups = ipv4Validator.match(inet4Address); if (groups == null) { return false; } // verify that address subgroups are legal for (int i = 0; i <= 3; i++) { String ipSegment = groups[i]; if (ipSegment == null || ipSegment.length() <= 0) { return false; } int iIpSegment = 0; try { iIpSegment = Integer.parseInt(ipSegment); } catch (NumberFormatException e) { return false; } if (iIpSegment > 255) { return false; } } return true; } }