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.james.util; import java.util.List; import java.util.Optional; import com.github.steveash.guavate.Guavate; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Objects; import com.google.common.base.Preconditions; import com.google.common.base.Splitter; import com.google.common.base.Strings; import com.google.common.collect.ImmutableList; public class Host { public static ImmutableList<Host> parseHosts(String hostsString) { return parseHosts(hostsString, Optional.empty()); } public static ImmutableList<Host> parseHosts(String hostsString, int defaultPort) { return parseHosts(hostsString, Optional.of(defaultPort)); } private static ImmutableList<Host> parseHosts(String hostsString, Optional<Integer> defaultPort) { return Splitter.on(',').omitEmptyStrings().splitToList(hostsString).stream() .map(string -> Host.parse(string, defaultPort)).distinct().collect(Guavate.toImmutableList()); } public static Host from(String hostname, int port) { return new Host(hostname, port); } public static Host parseConfString(String ipAndPort, int defaultPort) { return parse(ipAndPort, Optional.of(defaultPort)); } public static Host parseConfString(String ipAndPort) { return parse(ipAndPort, Optional.empty()); } private static Host parse(String ipAndPort, Optional<Integer> defaultPort) { Preconditions.checkNotNull(ipAndPort); Preconditions.checkArgument(!ipAndPort.isEmpty()); List<String> parts = retrieveHostParts(ipAndPort); String ip = parts.get(0); int port = getPortFromConfPart(parts, defaultPort); return new Host(ip, port); } private static List<String> retrieveHostParts(String ipAndPort) { List<String> parts = Splitter.on(':').trimResults().splitToList(ipAndPort); if (parts.size() < 1 || parts.size() > 2) { throw new IllegalArgumentException(ipAndPort + " is not a valid cassandra node"); } return parts; } private static int getPortFromConfPart(List<String> parts, Optional<Integer> defaultPort) { if (parts.size() == 2) { return Integer.valueOf(parts.get(1)); } if (parts.size() == 1) { return defaultPort.orElseThrow( () -> new IllegalArgumentException("Host do not have port part but no default port provided")); } throw new RuntimeException( "A host should be either a hostname or a hostname and a port separated by a ':'"); } private final String hostName; private final int port; @VisibleForTesting Host(String hostName, int port) { Preconditions.checkNotNull(hostName, "Hostname could not be null"); Preconditions.checkArgument(!Strings.isNullOrEmpty(hostName), "Hostname could not be empty"); Preconditions.checkArgument(port > 0 && port <= 65535, "Port should be between 0 and 65535"); this.hostName = hostName; this.port = port; } public String getHostName() { return hostName; } public int getPort() { return port; } @Override public final int hashCode() { return Objects.hashCode(hostName, port); } @Override public final boolean equals(Object object) { if (object instanceof Host) { Host that = (Host) object; return Objects.equal(this.hostName, that.hostName) && Objects.equal(this.port, that.port); } return false; } @Override public String toString() { return this.hostName + ":" + this.port; } }