001/* 002 * oauth2-oidc-sdk 003 * 004 * Copyright 2012-2016, Connect2id Ltd and contributors. 005 * 006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use 007 * this file except in compliance with the License. You may obtain a copy of the 008 * License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software distributed 013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR 014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the 015 * specific language governing permissions and limitations under the License. 016 */ 017 018package com.nimbusds.oauth2.sdk.util; 019 020 021import java.util.*; 022 023 024/** 025 * Multi-valued map utilities. 026 */ 027public final class MultivaluedMapUtils { 028 029 030 /** 031 * Converts the specified multi-valued map to a single-valued map by 032 * taking the first value in the list. 033 * 034 * @param map The multi-valued map, {@code null} if not specified. 035 * 036 * @return The single-valued map, {@code null} if no map was specified. 037 */ 038 public static <K,V> Map<K,V> toSingleValuedMap(final Map<K,List<V>> map) { 039 040 if (map == null) 041 return null; 042 043 Map<K,V> out = new HashMap<>(); 044 045 for (Map.Entry<K,List<V>> en: map.entrySet()) { 046 047 if (en.getValue() == null || en.getValue().isEmpty()) { 048 out.put(en.getKey(), null); 049 } else { 050 out.put(en.getKey(), en.getValue().get(0)); 051 } 052 } 053 054 return out; 055 } 056 057 058 /** 059 * Gets the first value for the specified key. 060 * 061 * @param map The multi-valued map. Must not be {@code null}. 062 * @param key The key. Must not be {@code null}. 063 * 064 * @return The first value, {@code null} if not set. 065 */ 066 public static <K,V> V getFirstValue(final Map<K,List<V>> map, final K key) { 067 068 List<V> valueList = map.get(key); 069 070 if (valueList == null || valueList.isEmpty()) { 071 return null; 072 } 073 074 return valueList.get(0); 075 } 076 077 078 /** 079 * Removes the entry for the specified key and returns its first value. 080 * 081 * @param map The multi-valued map. Must not be {@code null}. 082 * @param key The key. Must not be {@code null}. 083 * 084 * @return The first value, {@code null} if not set. 085 */ 086 public static <K,V> V removeAndReturnFirstValue(final Map<K,List<V>> map, final String key) { 087 088 List<V> valueList = map.remove(key); 089 090 if (valueList == null || valueList.isEmpty()) { 091 return null; 092 } 093 094 return valueList.get(0); 095 } 096 097 098 /** 099 * Returns the keys with more than one distinct value. Keys that map to 100 * two or more identical values are treated as single-valued. 101 * 102 * @param map The multi-valued map, {@code null} if not specified. 103 * @param excepted The excepted keys, {@code null} or empty if none. 104 * 105 * @return The keys with more than one distinct value, empty set if 106 * none. 107 */ 108 public static <K,V> Set<K> getKeysWithMoreThanOneValue(final Map<K,List<V>> map, final Set<K> excepted) { 109 110 if (MapUtils.isEmpty(map)) { 111 return Collections.emptySet(); 112 } 113 114 Set<K> found = new HashSet<>(); 115 for (Map.Entry<K,List<V>> en: map.entrySet()) { 116 117 if (CollectionUtils.contains(excepted, en.getKey())) { 118 continue; 119 } 120 121 Set<V> entryValues = new HashSet<>(en.getValue()); 122 123 if (CollectionUtils.isNotEmpty(entryValues) && entryValues.size() > 1) { 124 found.add(en.getKey()); 125 } 126 } 127 return found; 128 } 129 130 131 /** 132 * Prevents public instantiation. 133 */ 134 private MultivaluedMapUtils() {} 135}