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Diffstat (limited to 'framework/src/onos/core/api/src/main/java/org/onosproject/store/service/EventuallyConsistentMap.java')
| -rw-r--r-- | framework/src/onos/core/api/src/main/java/org/onosproject/store/service/EventuallyConsistentMap.java | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/EventuallyConsistentMap.java b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/EventuallyConsistentMap.java new file mode 100644 index 00000000..06395b8e --- /dev/null +++ b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/EventuallyConsistentMap.java @@ -0,0 +1,207 @@ +/* + * Copyright 2015 Open Networking Laboratory + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.onosproject.store.service; + +import java.util.Collection; +import java.util.Map; +import java.util.Set; +import java.util.function.BiFunction; + +/** + * A distributed, eventually consistent map. + * <p> + * This map does not offer read after writes consistency. Operations are + * serialized via the timestamps issued by the clock service. If two updates + * are in conflict, the update with the more recent timestamp will endure. + * </p><p> + * The interface is mostly similar to {@link java.util.Map} with some minor + * semantic changes and the addition of a listener framework (because the map + * can be mutated by clients on other instances, not only through the local Java + * API). + * </p><p> + * Clients are expected to register an + * {@link EventuallyConsistentMapListener} if they + * are interested in receiving notifications of update to the map. + * </p><p> + * Null values are not allowed in this map. + * </p> + */ +public interface EventuallyConsistentMap<K, V> { + + /** + * Returns the number of key-value mappings in this map. + * + * @return number of key-value mappings + */ + int size(); + + /** + * Returns true if this map is empty. + * + * @return true if this map is empty, otherwise false + */ + boolean isEmpty(); + + /** + * Returns true if the map contains a mapping for the specified key. + * + * @param key the key to check if this map contains + * @return true if this map has a mapping for the key, otherwise false + */ + boolean containsKey(K key); + + /** + * Returns true if the map contains a mapping from any key to the specified + * value. + * + * @param value the value to check if this map has a mapping for + * @return true if this map has a mapping to this value, otherwise false + */ + boolean containsValue(V value); + + /** + * Returns the value mapped to the specified key. + * + * @param key the key to look up in this map + * @return the value mapped to the key, or null if no mapping is found + */ + V get(K key); + + /** + * Associates the specified value to the specified key in this map. + * <p> + * Note: this differs from the specification of {@link java.util.Map} + * because it does not return the previous value associated with the key. + * Clients are expected to register an + * {@link EventuallyConsistentMapListener} if + * they are interested in receiving notification of updates to the map. + * </p><p> + * Null values are not allowed in the map. + * </p> + * + * @param key the key to add a mapping for in this map + * @param value the value to associate with the key in this map + */ + void put(K key, V value); + + /** + * Removes the mapping associated with the specified key from the map. + * <p> + * Clients are expected to register an {@link EventuallyConsistentMapListener} if + * they are interested in receiving notification of updates to the map. + * </p> + * + * @param key the key to remove the mapping for + * @return previous value associated with key, or null if there was no mapping for key. + */ + V remove(K key); + + /** + * Removes the given key-value mapping from the map, if it exists. + * <p> + * This actually means remove any values up to and including the timestamp + * given by the map's timestampProvider. + * Any mappings that produce an earlier timestamp than this given key-value + * pair will be removed, and any mappings that produce a later timestamp + * will supersede this remove. + * </p><p> + * Note: this differs from the specification of {@link java.util.Map} + * because it does not return a boolean indication whether a value was removed. + * Clients are expected to register an + * {@link EventuallyConsistentMapListener} if + * they are interested in receiving notification of updates to the map. + * </p> + * + * @param key the key to remove the mapping for + * @param value the value mapped to the key + */ + void remove(K key, V value); + + /** + * Attempts to compute a mapping for the specified key and its current mapped + * value (or null if there is no current mapping). + * <p> + * If the function returns null, the mapping is removed (or remains absent if initially absent). + * @param key map key + * @param recomputeFunction function to recompute a new value + * @return new value + */ + V compute(K key, BiFunction<K, V, V> recomputeFunction); + + /** + * Adds mappings for all key-value pairs in the specified map to this map. + * <p> + * This will be more efficient in communication than calling individual put + * operations. + * </p> + * + * @param m a map of values to add to this map + */ + void putAll(Map<? extends K, ? extends V> m); + + /** + * Removes all mappings from this map. + */ + void clear(); + + /** + * Returns a set of the keys in this map. Changes to the set are not + * reflected back to the map. + * + * @return set of keys in the map + */ + Set<K> keySet(); + + /** + * Returns a collections of values in this map. Changes to the collection + * are not reflected back to the map. + * + * @return collection of values in the map + */ + Collection<V> values(); + + /** + * Returns a set of mappings contained in this map. Changes to the set are + * not reflected back to the map. + * + * @return set of key-value mappings in this map + */ + Set<Map.Entry<K, V>> entrySet(); + + /** + * Adds the specified listener to the map which will be notified whenever + * the mappings in the map are changed. + * + * @param listener listener to register for events + */ + void addListener(EventuallyConsistentMapListener<K, V> listener); + + /** + * Removes the specified listener from the map such that it will no longer + * receive change notifications. + * + * @param listener listener to deregister for events + */ + void removeListener(EventuallyConsistentMapListener<K, V> listener); + + /** + * Shuts down the map and breaks communication between different instances. + * This allows the map objects to be cleaned up and garbage collected. + * Calls to any methods on the map subsequent to calling destroy() will + * throw a {@link java.lang.RuntimeException}. + */ + void destroy(); +} |