Yuta HIGUCHI | a8016e7 | 2014-11-18 20:19:46 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2014 Open Networking Laboratory |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.onlab.onos.store.service.impl; |
| 18 | |
| 19 | import static com.google.common.base.Preconditions.checkNotNull; |
| 20 | import static com.google.common.base.Predicates.notNull; |
| 21 | |
| 22 | import java.util.Map; |
| 23 | |
| 24 | import org.onlab.onos.store.serializers.StoreSerializer; |
| 25 | import org.onlab.onos.store.service.DatabaseAdminService; |
| 26 | import org.onlab.onos.store.service.DatabaseService; |
| 27 | import org.onlab.onos.store.service.VersionedValue; |
| 28 | |
| 29 | import com.google.common.base.Function; |
| 30 | import com.google.common.cache.CacheBuilder; |
| 31 | import com.google.common.cache.CacheLoader; |
| 32 | import com.google.common.cache.LoadingCache; |
| 33 | import com.google.common.collect.FluentIterable; |
| 34 | |
| 35 | /** |
| 36 | * Map like interface wrapper around DatabaseService. |
| 37 | * |
| 38 | * @param <K> Key type of the map. |
| 39 | * The type must have toString(), which can uniquely identify the entry. |
| 40 | * @param <V> Value type |
| 41 | */ |
| 42 | public class CMap<K, V> { |
| 43 | |
| 44 | @SuppressWarnings("unused") |
| 45 | private final DatabaseAdminService dbAdminService; |
| 46 | |
| 47 | private final DatabaseService dbService; |
| 48 | |
| 49 | private final String tableName; |
| 50 | private final StoreSerializer serializer; |
| 51 | |
| 52 | private final LoadingCache<K, String> keyCache; |
| 53 | |
| 54 | /** |
| 55 | * Creates a CMap instance. |
| 56 | * It will create the table if necessary. |
| 57 | * |
| 58 | * @param dbAdminService |
| 59 | * @param dbService |
| 60 | * @param tableName table which this Map corresponds to |
| 61 | * @param serializer Value serializer |
| 62 | */ |
| 63 | public CMap(DatabaseAdminService dbAdminService, |
| 64 | DatabaseService dbService, |
| 65 | String tableName, |
| 66 | StoreSerializer serializer) { |
| 67 | |
| 68 | this.dbAdminService = checkNotNull(dbAdminService); |
| 69 | this.dbService = checkNotNull(dbService); |
| 70 | this.tableName = checkNotNull(tableName); |
| 71 | this.serializer = checkNotNull(serializer); |
| 72 | |
| 73 | if (!dbAdminService.listTables().contains(tableName)) { |
| 74 | dbAdminService.createTable(tableName); |
| 75 | } |
| 76 | |
| 77 | keyCache = CacheBuilder.newBuilder() |
| 78 | .softValues() |
| 79 | .build(new CacheLoader<K, String>() { |
| 80 | |
| 81 | @Override |
| 82 | public String load(K key) { |
| 83 | return key.toString(); |
| 84 | } |
| 85 | }); |
| 86 | } |
| 87 | |
| 88 | protected String sK(K key) { |
| 89 | return keyCache.getUnchecked(key); |
| 90 | } |
| 91 | |
| 92 | protected byte[] sV(V val) { |
| 93 | return serializer.encode(val); |
| 94 | } |
| 95 | |
| 96 | protected V dV(byte[] valBytes) { |
| 97 | return serializer.decode(valBytes); |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Puts an entry to the map, if not already present. |
| 102 | * |
| 103 | * @param key the key of the value to put if absent |
| 104 | * @param value the value to be put if previous value does not exist |
| 105 | * @return true if put was successful. |
| 106 | */ |
| 107 | public boolean putIfAbsent(K key, V value) { |
| 108 | return dbService.putIfAbsent(tableName, sK(key), sV(value)); |
| 109 | } |
| 110 | |
| 111 | /** |
| 112 | * Removes an entry associated to specified key. |
| 113 | * |
| 114 | * @param key key of the value to remove |
| 115 | * @return previous value in the map for the key |
| 116 | */ |
| 117 | public V remove(K key) { |
| 118 | VersionedValue removed = dbService.remove(tableName, sK(key)); |
| 119 | if (removed == null) { |
| 120 | return null; |
| 121 | } |
| 122 | return dV(removed.value()); |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Returns the size of the map. |
| 127 | * |
| 128 | * @return size of the map |
| 129 | */ |
| 130 | public long size() { |
| 131 | // TODO this is very inefficient |
| 132 | return dbService.getAll(tableName).size(); |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Returns all the values contained in the map. |
| 137 | * |
| 138 | * @return values containd in this map |
| 139 | */ |
| 140 | public Iterable<V> values() { |
| 141 | Map<String, VersionedValue> all = dbService.getAll(tableName); |
| 142 | return FluentIterable.from(all.values()) |
| 143 | .transform(new Function<VersionedValue, V>() { |
| 144 | |
| 145 | @Override |
| 146 | public V apply(VersionedValue input) { |
| 147 | if (input == null) { |
| 148 | return null; |
| 149 | } |
| 150 | return dV(input.value()); |
| 151 | } |
| 152 | }) |
| 153 | .filter(notNull()); |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Gets the value in the map. |
| 158 | * |
| 159 | * @param key to get from the map |
| 160 | * @return value associated with the key, null if not such entry |
| 161 | */ |
| 162 | public V get(K key) { |
| 163 | VersionedValue vv = dbService.get(tableName, sK(key)); |
| 164 | if (vv == null) { |
| 165 | return null; |
| 166 | } |
| 167 | return dV(vv.value()); |
| 168 | } |
| 169 | |
| 170 | /** |
| 171 | * Replaces the value in the map if the value matches the expected. |
| 172 | * |
| 173 | * @param key of the entry to replace |
| 174 | * @param oldVal value expected to be in the map |
| 175 | * @param newVal value to be replaced with |
| 176 | * @return true if successfully replaced |
| 177 | */ |
| 178 | public boolean replace(K key, V oldVal, V newVal) { |
| 179 | return dbService.putIfValueMatches(tableName, sK(key), sV(oldVal), sV(newVal)); |
| 180 | } |
| 181 | |
| 182 | /** |
| 183 | * Puts a value int the map. |
| 184 | * |
| 185 | * @param key key with which the specified value is to be associated |
| 186 | * @param value value to be associated with the specified key |
| 187 | * @return previous value or null if not such entry |
| 188 | */ |
| 189 | public V put(K key, V value) { |
| 190 | VersionedValue vv = dbService.put(tableName, sK(key), sV(value)); |
| 191 | if (vv == null) { |
| 192 | return null; |
| 193 | } |
| 194 | return dV(vv.value()); |
| 195 | } |
| 196 | } |