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.hadoop.util; import java.net.InetAddress; import java.net.UnknownHostException; import java.util.ArrayList; import java.util.Collection; import java.util.HashSet; import java.util.LinkedList; import java.util.List; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.commons.net.util.SubnetUtils; import com.google.common.annotations.VisibleForTesting; import com.google.common.net.InetAddresses; /** * Container class which holds a list of ip/host addresses and * answers membership queries. * * Accepts list of ip addresses, ip addreses in CIDR format and/or * host addresses. */ public class MachineList { public static final Log LOG = LogFactory.getLog(MachineList.class); public static final String WILDCARD_VALUE = "*"; /** * InetAddressFactory is used to obtain InetAddress from host. * This class makes it easy to simulate host to ip mappings during testing. * */ public static class InetAddressFactory { static final InetAddressFactory S_INSTANCE = new InetAddressFactory(); public InetAddress getByName(String host) throws UnknownHostException { return InetAddress.getByName(host); } } private final boolean all; private final Set<String> ipAddresses; private final List<SubnetUtils.SubnetInfo> cidrAddresses; private final Set<String> hostNames; private final InetAddressFactory addressFactory; /** * * @param hostEntries comma separated ip/cidr/host addresses */ public MachineList(String hostEntries) { this(StringUtils.getTrimmedStringCollection(hostEntries)); } /** * * @param hostEntries collection of separated ip/cidr/host addresses */ public MachineList(Collection<String> hostEntries) { this(hostEntries, InetAddressFactory.S_INSTANCE); } /** * Accepts a collection of ip/cidr/host addresses * * @param hostEntries * @param addressFactory addressFactory to convert host to InetAddress */ public MachineList(Collection<String> hostEntries, InetAddressFactory addressFactory) { this.addressFactory = addressFactory; if (hostEntries != null) { if ((hostEntries.size() == 1) && (hostEntries.contains(WILDCARD_VALUE))) { all = true; ipAddresses = null; hostNames = null; cidrAddresses = null; } else { all = false; Set<String> ips = new HashSet<String>(); List<SubnetUtils.SubnetInfo> cidrs = new LinkedList<SubnetUtils.SubnetInfo>(); Set<String> hosts = new HashSet<String>(); for (String hostEntry : hostEntries) { //ip address range if (hostEntry.indexOf("/") > -1) { try { SubnetUtils subnet = new SubnetUtils(hostEntry); subnet.setInclusiveHostCount(true); cidrs.add(subnet.getInfo()); } catch (IllegalArgumentException e) { LOG.warn("Invalid CIDR syntax : " + hostEntry); throw e; } } else if (InetAddresses.isInetAddress(hostEntry)) { //ip address ips.add(hostEntry); } else { //hostname hosts.add(hostEntry); } } ipAddresses = (ips.size() > 0) ? ips : null; cidrAddresses = (cidrs.size() > 0) ? cidrs : null; hostNames = (hosts.size() > 0) ? hosts : null; } } else { all = false; ipAddresses = null; hostNames = null; cidrAddresses = null; } } /** * Accepts an ip address and return true if ipAddress is in the list * @param ipAddress * @return true if ipAddress is part of the list */ public boolean includes(String ipAddress) { if (all) { return true; } if (ipAddress == null) { throw new IllegalArgumentException("ipAddress is null."); } //check in the set of ipAddresses if ((ipAddresses != null) && ipAddresses.contains(ipAddress)) { return true; } //iterate through the ip ranges for inclusion if (cidrAddresses != null) { for (SubnetUtils.SubnetInfo cidrAddress : cidrAddresses) { if (cidrAddress.isInRange(ipAddress)) { return true; } } } //check if the ipAddress matches one of hostnames if (hostNames != null) { //convert given ipAddress to hostname and look for a match InetAddress hostAddr; try { hostAddr = addressFactory.getByName(ipAddress); if ((hostAddr != null) && hostNames.contains(hostAddr.getCanonicalHostName())) { return true; } } catch (UnknownHostException e) { //ignore the exception and proceed to resolve the list of hosts } //loop through host addresses and convert them to ip and look for a match for (String host : hostNames) { try { hostAddr = addressFactory.getByName(host); } catch (UnknownHostException e) { continue; } if (hostAddr.getHostAddress().equals(ipAddress)) { return true; } } } return false; } /** * returns the contents of the MachineList as a Collection<String> * This can be used for testing * @return contents of the MachineList */ @VisibleForTesting public Collection<String> getCollection() { Collection<String> list = new ArrayList<String>(); if (all) { list.add("*"); } else { if (ipAddresses != null) { list.addAll(ipAddresses); } if (hostNames != null) { list.addAll(hostNames); } if (cidrAddresses != null) { for (SubnetUtils.SubnetInfo cidrAddress : cidrAddresses) { list.add(cidrAddress.getCidrSignature()); } } } return list; } }