001    /*
002     * Util.java
003     *
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *     http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing, software
015     * distributed under the License is distributed on an "AS IS" BASIS,
016     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017     * See the License for the specific language governing permissions and
018     * limitations under the License.
019     */
020    
021    
022    package org.apache.hadoop.metrics2.util;
023    
024    import java.net.InetSocketAddress;
025    import java.util.List;
026    
027    import com.google.common.collect.Lists;
028    
029    import org.apache.hadoop.classification.InterfaceAudience;
030    import org.apache.hadoop.classification.InterfaceStability;
031    import org.apache.hadoop.net.NetUtils;
032    
033    /**
034     * Helpers to handle server addresses
035     */
036    @InterfaceAudience.Public
037    @InterfaceStability.Evolving
038    public class Servers {
039      /**
040       * This class is not intended to be instantiated
041       */
042      private Servers() {}
043    
044      /**
045       * Parses a space and/or comma separated sequence of server specifications
046       * of the form <i>hostname</i> or <i>hostname:port</i>.  If
047       * the specs string is null, defaults to localhost:defaultPort.
048       *
049       * @param specs   server specs (see description)
050       * @param defaultPort the default port if not specified
051       * @return a list of InetSocketAddress objects.
052       */
053      public static List<InetSocketAddress> parse(String specs, int defaultPort) {
054        List<InetSocketAddress> result = Lists.newArrayList();
055        if (specs == null) {
056          result.add(new InetSocketAddress("localhost", defaultPort));
057        }
058        else {
059          String[] specStrings = specs.split("[ ,]+");
060          for (String specString : specStrings) {
061            result.add(NetUtils.createSocketAddr(specString, defaultPort));
062          }
063        }
064        return result;
065      }
066    }