1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 package org.apache.hadoop.hbase.util; 20 21 import com.google.common.collect.Lists; 22 import org.apache.commons.lang.StringUtils; 23 import org.apache.hadoop.conf.Configuration; 24 import org.apache.hadoop.hbase.classification.InterfaceAudience; 25 import org.apache.hadoop.hbase.classification.InterfaceStability; 26 27 import java.util.AbstractMap; 28 import java.util.Collection; 29 import java.util.List; 30 import java.util.Map; 31 32 /** 33 * Utilities for storing more complex collection types in 34 * {@link org.apache.hadoop.conf.Configuration} instances. 35 */ 36 @InterfaceAudience.Public 37 @InterfaceStability.Evolving 38 public final class ConfigurationUtil { 39 // TODO: hopefully this is a good delimiter; it's not in the base64 alphabet, 40 // nor is it valid for paths 41 public static final char KVP_DELIMITER = '^'; 42 43 // Disallow instantiation 44 private ConfigurationUtil() { 45 46 } 47 48 /** 49 * Store a collection of Map.Entry's in conf, with each entry separated by ',' 50 * and key values delimited by {@link #KVP_DELIMITER} 51 * 52 * @param conf configuration to store the collection in 53 * @param key overall key to store keyValues under 54 * @param keyValues kvps to be stored under key in conf 55 */ 56 public static void setKeyValues(Configuration conf, String key, 57 Collection<Map.Entry<String, String>> keyValues) { 58 setKeyValues(conf, key, keyValues, KVP_DELIMITER); 59 } 60 61 /** 62 * Store a collection of Map.Entry's in conf, with each entry separated by ',' 63 * and key values delimited by delimiter. 64 * 65 * @param conf configuration to store the collection in 66 * @param key overall key to store keyValues under 67 * @param keyValues kvps to be stored under key in conf 68 * @param delimiter character used to separate each kvp 69 */ 70 public static void setKeyValues(Configuration conf, String key, 71 Collection<Map.Entry<String, String>> keyValues, char delimiter) { 72 List<String> serializedKvps = Lists.newArrayList(); 73 74 for (Map.Entry<String, String> kvp : keyValues) { 75 serializedKvps.add(kvp.getKey() + delimiter + kvp.getValue()); 76 } 77 78 conf.setStrings(key, serializedKvps.toArray(new String[serializedKvps.size()])); 79 } 80 81 /** 82 * Retrieve a list of key value pairs from configuration, stored under the provided key 83 * 84 * @param conf configuration to retrieve kvps from 85 * @param key key under which the key values are stored 86 * @return the list of kvps stored under key in conf, or null if the key isn't present. 87 * @see #setKeyValues(Configuration, String, Collection, char) 88 */ 89 public static List<Map.Entry<String, String>> getKeyValues(Configuration conf, String key) { 90 return getKeyValues(conf, key, KVP_DELIMITER); 91 } 92 93 /** 94 * Retrieve a list of key value pairs from configuration, stored under the provided key 95 * 96 * @param conf configuration to retrieve kvps from 97 * @param key key under which the key values are stored 98 * @param delimiter character used to separate each kvp 99 * @return the list of kvps stored under key in conf, or null if the key isn't present. 100 * @see #setKeyValues(Configuration, String, Collection, char) 101 */ 102 public static List<Map.Entry<String, String>> getKeyValues(Configuration conf, String key, 103 char delimiter) { 104 String[] kvps = conf.getStrings(key); 105 106 if (kvps == null) { 107 return null; 108 } 109 110 List<Map.Entry<String, String>> rtn = Lists.newArrayList(); 111 112 for (String kvp : kvps) { 113 String[] splitKvp = StringUtils.split(kvp, delimiter); 114 115 if (splitKvp.length != 2) { 116 throw new IllegalArgumentException( 117 "Expected key value pair for configuration key '" + key + "'" + " to be of form '<key>" 118 + delimiter + "<value>; was " + kvp + " instead"); 119 } 120 121 rtn.add(new AbstractMap.SimpleImmutableEntry<String, String>(splitKvp[0], splitKvp[1])); 122 } 123 return rtn; 124 } 125 }