Madan Jampani | 0934270 | 2015-02-05 23:32:40 -0800 | [diff] [blame^] | 1 | package org.onosproject.store.consistent.impl; |
| 2 | |
| 3 | import java.util.Collection; |
| 4 | import java.util.List; |
| 5 | import java.util.Set; |
| 6 | import java.util.Map.Entry; |
| 7 | |
| 8 | /** |
| 9 | * A distributed, strongly consistent map. |
| 10 | * <p> |
| 11 | * This map offers strong read-after-update (where update == create/update/delete) |
| 12 | * consistency. All operations to the map are serialized and applied in a consistent |
| 13 | * manner. |
| 14 | * <p> |
| 15 | * The stronger consistency comes at the expense of availability in |
| 16 | * the event of a network partition. A network partition can be either due to |
| 17 | * a temporary disruption in network connectivity between participating nodes |
| 18 | * or due to a node being temporarily down. |
| 19 | * </p><p> |
| 20 | * All values stored in this map are versioned and the API supports optimistic |
| 21 | * concurrency by allowing conditional updates that take into consideration |
| 22 | * the version or value that was previously read. |
| 23 | * </p><p> |
| 24 | * The map also supports atomic batch updates (transactions). One can provide a list |
| 25 | * of updates to be applied atomically if and only if all the operations are guaranteed |
| 26 | * to succeed i.e. all their preconditions are met. For example, the precondition |
| 27 | * for a putIfAbsent API call is absence of a mapping for the key. Similarly, the |
| 28 | * precondition for a conditional replace operation is the presence of an expected |
| 29 | * version or value |
| 30 | * </p><p> |
| 31 | * This map does not allow null values. All methods can throw a ConsistentMapException |
| 32 | * (which extends RuntimeException) to indicate failures. |
| 33 | * |
| 34 | */ |
| 35 | public interface ConsistentMap<K, V> { |
| 36 | |
| 37 | /** |
| 38 | * Returns the number of entries in the map. |
| 39 | * |
| 40 | * @return map size. |
| 41 | */ |
| 42 | int size(); |
| 43 | |
| 44 | /** |
| 45 | * Returns true if the map is empty. |
| 46 | * |
| 47 | * @return true if map has no entries, false otherwise. |
| 48 | */ |
| 49 | boolean isEmpty(); |
| 50 | |
| 51 | /** |
| 52 | * Returns true if this map contains a mapping for the specified key. |
| 53 | * |
| 54 | * @param key key |
| 55 | * @return true if map contains key, false otherwise. |
| 56 | */ |
| 57 | boolean containsKey(K key); |
| 58 | |
| 59 | /** |
| 60 | * Returns true if this map contains the specified value. |
| 61 | * |
| 62 | * @param value value |
| 63 | * @return true if map contains value, false otherwise. |
| 64 | */ |
| 65 | boolean containsValue(V value); |
| 66 | |
| 67 | /** |
| 68 | * Returns the value (and version) to which the specified key is mapped, or null if this |
| 69 | * map contains no mapping for the key. |
| 70 | * |
| 71 | * @param key the key whose associated value (and version) is to be returned |
| 72 | * @return the value (and version) to which the specified key is mapped, or null if |
| 73 | * this map contains no mapping for the key |
| 74 | */ |
| 75 | Versioned<V> get(K key); |
| 76 | |
| 77 | /** |
| 78 | * Associates the specified value with the specified key in this map (optional operation). |
| 79 | * If the map previously contained a mapping for the key, the old value is replaced by the |
| 80 | * specified value. |
| 81 | * |
| 82 | * @param key key with which the specified value is to be associated |
| 83 | * @param value value to be associated with the specified key |
| 84 | * @return the previous value (and version) associated with key, or null if there was |
| 85 | * no mapping for key. |
| 86 | */ |
| 87 | Versioned<V> put(K key, V value); |
| 88 | |
| 89 | /** |
| 90 | * Removes the mapping for a key from this map if it is present (optional operation). |
| 91 | * |
| 92 | * @param key key whose value is to be removed from the map |
| 93 | * @return the value (and version) to which this map previously associated the key, |
| 94 | * or null if the map contained no mapping for the key. |
| 95 | */ |
| 96 | Versioned<V> remove(K key); |
| 97 | |
| 98 | /** |
| 99 | * Removes all of the mappings from this map (optional operation). |
| 100 | * The map will be empty after this call returns. |
| 101 | */ |
| 102 | void clear(); |
| 103 | |
| 104 | /** |
| 105 | * Returns a Set view of the keys contained in this map. |
| 106 | * This method differs from the behavior of java.util.Map.keySet() in that |
| 107 | * what is returned is a unmodifiable snapshot view of the keys in the ConsistentMap. |
| 108 | * Attempts to modify the returned set, whether direct or via its iterator, |
| 109 | * result in an UnsupportedOperationException. |
| 110 | * |
| 111 | * @return a set of the keys contained in this map |
| 112 | */ |
| 113 | Set<K> keySet(); |
| 114 | |
| 115 | /** |
| 116 | * Returns the collection of values (and associated versions) contained in this map. |
| 117 | * This method differs from the behavior of java.util.Map.values() in that |
| 118 | * what is returned is a unmodifiable snapshot view of the values in the ConsistentMap. |
| 119 | * Attempts to modify the returned collection, whether direct or via its iterator, |
| 120 | * result in an UnsupportedOperationException. |
| 121 | * |
| 122 | * @return a collection of the values (and associated versions) contained in this map |
| 123 | */ |
| 124 | Collection<Versioned<V>> values(); |
| 125 | |
| 126 | /** |
| 127 | * Returns the set of entries contained in this map. |
| 128 | * This method differs from the behavior of java.util.Map.entrySet() in that |
| 129 | * what is returned is a unmodifiable snapshot view of the entries in the ConsistentMap. |
| 130 | * Attempts to modify the returned set, whether direct or via its iterator, |
| 131 | * result in an UnsupportedOperationException. |
| 132 | * |
| 133 | * @return set of entries contained in this map. |
| 134 | */ |
| 135 | Set<Entry<K, Versioned<V>>> entrySet(); |
| 136 | |
| 137 | /** |
| 138 | * If the specified key is not already associated with a value |
| 139 | * associates it with the given value and returns null, else returns the current value. |
| 140 | * |
| 141 | * @param key key with which the specified value is to be associated |
| 142 | * @param value value to be associated with the specified key |
| 143 | * @return the previous value associated with the specified key or null |
| 144 | * if key does not already mapped to a value. |
| 145 | */ |
| 146 | Versioned<V> putIfAbsent(K key, V value); |
| 147 | |
| 148 | /** |
| 149 | * Removes the entry for the specified key only if it is currently |
| 150 | * mapped to the specified value. |
| 151 | * |
| 152 | * @param key key with which the specified value is associated |
| 153 | * @param value value expected to be associated with the specified key |
| 154 | * @return true if the value was removed |
| 155 | */ |
| 156 | boolean remove(K key, V value); |
| 157 | |
| 158 | /** |
| 159 | * Removes the entry for the specified key only if its current |
| 160 | * version in the map is equal to the specified version. |
| 161 | * |
| 162 | * @param key key with which the specified version is associated |
| 163 | * @param version version expected to be associated with the specified key |
| 164 | * @return true if the value was removed |
| 165 | */ |
| 166 | boolean remove(K key, long version); |
| 167 | |
| 168 | /** |
| 169 | * Replaces the entry for the specified key only if currently mapped |
| 170 | * to the specified value. |
| 171 | * |
| 172 | * @param key key with which the specified value is associated |
| 173 | * @param oldValue value expected to be associated with the specified key |
| 174 | * @param newValue value to be associated with the specified key |
| 175 | * @return true if the value was replaced |
| 176 | */ |
| 177 | boolean replace(K key, V oldValue, V newValue); |
| 178 | |
| 179 | /** |
| 180 | * Replaces the entry for the specified key only if it is currently mapped to the |
| 181 | * specified version. |
| 182 | * |
| 183 | * @param key key key with which the specified value is associated |
| 184 | * @param oldVersion version expected to be associated with the specified key |
| 185 | * @param newValue value to be associated with the specified key |
| 186 | * @return true if the value was replaced |
| 187 | */ |
| 188 | boolean replace(K key, long oldVersion, V newValue); |
| 189 | |
| 190 | /** |
| 191 | * Atomically apply the specified list of updates to the map. |
| 192 | * If any of the updates cannot be applied due to a precondition |
| 193 | * violation, none of the updates will be applied and the state of |
| 194 | * the map remains unaltered. |
| 195 | * |
| 196 | * @param updates list of updates to apply atomically. |
| 197 | * @return true if the map was updated. |
| 198 | */ |
| 199 | boolean batchUpdate(List<UpdateOperation<K, V>> updates); |
| 200 | } |