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Diffstat (limited to 'framework/src/onos/core/api/src/main/java/org/onosproject/store/service/ConsistentMap.java')
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diff --git a/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/ConsistentMap.java b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/ConsistentMap.java new file mode 100644 index 00000000..289da202 --- /dev/null +++ b/framework/src/onos/core/api/src/main/java/org/onosproject/store/service/ConsistentMap.java @@ -0,0 +1,291 @@ +/* + * 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.Map.Entry; +import java.util.Set; +import java.util.function.BiFunction; +import java.util.function.Function; +import java.util.function.Predicate; + +/** + * A distributed, strongly consistent key-value map. + * <p> + * This map offers strong read-after-update (where update == create/update/delete) + * consistency. All operations to the map are serialized and applied in a consistent + * manner. + * <p> + * The stronger consistency comes at the expense of availability in + * the event of a network partition. A network partition can be either due to + * a temporary disruption in network connectivity between participating nodes + * or due to a node being temporarily down. + * </p><p> + * All values stored in this map are versioned and the API supports optimistic + * concurrency by allowing conditional updates that take into consideration + * the version or value that was previously read. + * </p><p> + * This map does not allow null values. All methods can throw a ConsistentMapException + * (which extends RuntimeException) to indicate failures. + * + */ +public interface ConsistentMap<K, V> { + + /** + * Returns the number of entries in the map. + * + * @return map size. + */ + int size(); + + /** + * Returns true if the map is empty. + * + * @return true if map has no entries, false otherwise + */ + boolean isEmpty(); + + /** + * Returns true if this map contains a mapping for the specified key. + * + * @param key key + * @return true if map contains key, false otherwise + */ + boolean containsKey(K key); + + /** + * Returns true if this map contains the specified value. + * + * @param value value + * @return true if map contains value, false otherwise. + */ + boolean containsValue(V value); + + /** + * Returns the value (and version) to which the specified key is mapped, or null if this + * map contains no mapping for the key. + * + * @param key the key whose associated value (and version) is to be returned + * @return the value (and version) to which the specified key is mapped, or null if + * this map contains no mapping for the key + */ + Versioned<V> get(K key); + + /** + * If the specified key is not already associated with a value (or is mapped to null), + * attempts to compute its value using the given mapping function and enters it into + * this map unless null. + * + * @param key key with which the specified value is to be associated + * @param mappingFunction the function to compute a value + * @return the current (existing or computed) value associated with the specified key, + * or null if the computed value is null. Method throws {@code ConsistentMapException.ConcurrentModification} + * if a concurrent modification of map is detected + */ + Versioned<V> computeIfAbsent(K key, + Function<? super K, ? extends V> mappingFunction); + + /** + * Attempts to compute a mapping for the specified key and its current mapped value (or + * null if there is no current mapping). + * If the computed value is null, the current mapping will be removed from the map. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none. + * This method throws {@code ConsistentMapException.ConcurrentModification} + * if a concurrent modification of map is detected + */ + Versioned<V> compute(K key, + BiFunction<? super K, ? super V, ? extends V> remappingFunction); + + /** + * If the value for the specified key is present and non-null, attempts to compute a new + * mapping given the key and its current mapped value. + * If the computed value is null, the current mapping will be removed from the map. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none. + * This method throws {@code ConsistentMapException.ConcurrentModification} + * if a concurrent modification of map is detected + */ + Versioned<V> computeIfPresent(K key, + BiFunction<? super K, ? super V, ? extends V> remappingFunction); + + /** + * If the value for the specified key satisfies a condition, attempts to compute a new + * mapping given the key and its current mapped value. + * If the computed value is null, the current mapping will be removed from the map. + * + * @param key key with which the specified value is to be associated + * @param condition condition that should evaluate to true for the computation to proceed + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or the old value if condition evaluates to false. + * This method throws {@code ConsistentMapException.ConcurrentModification} if a concurrent + * modification of map is detected + */ + Versioned<V> computeIf(K key, + Predicate<? super V> condition, + BiFunction<? super K, ? super V, ? extends V> remappingFunction); + + /** + * Associates the specified value with the specified key in this map (optional operation). + * If the map previously contained a mapping for the key, the old value is replaced by the + * specified value. + * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @return the previous value (and version) associated with key, or null if there was + * no mapping for key. + */ + Versioned<V> put(K key, V value); + + /** + * Associates the specified value with the specified key in this map (optional operation). + * If the map previously contained a mapping for the key, the old value is replaced by the + * specified value. + * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @return new value. + */ + Versioned<V> putAndGet(K key, V value); + + /** + * Removes the mapping for a key from this map if it is present (optional operation). + * + * @param key key whose value is to be removed from the map + * @return the value (and version) to which this map previously associated the key, + * or null if the map contained no mapping for the key. + */ + Versioned<V> remove(K key); + + /** + * Removes all of the mappings from this map (optional operation). + * The map will be empty after this call returns. + */ + void clear(); + + /** + * Returns a Set view of the keys contained in this map. + * This method differs from the behavior of java.util.Map.keySet() in that + * what is returned is a unmodifiable snapshot view of the keys in the ConsistentMap. + * Attempts to modify the returned set, whether direct or via its iterator, + * result in an UnsupportedOperationException. + * + * @return a set of the keys contained in this map + */ + Set<K> keySet(); + + /** + * Returns the collection of values (and associated versions) contained in this map. + * This method differs from the behavior of java.util.Map.values() in that + * what is returned is a unmodifiable snapshot view of the values in the ConsistentMap. + * Attempts to modify the returned collection, whether direct or via its iterator, + * result in an UnsupportedOperationException. + * + * @return a collection of the values (and associated versions) contained in this map + */ + Collection<Versioned<V>> values(); + + /** + * Returns the set of entries contained in this map. + * This method differs from the behavior of java.util.Map.entrySet() in that + * what is returned is a unmodifiable snapshot view of the entries in the ConsistentMap. + * Attempts to modify the returned set, whether direct or via its iterator, + * result in an UnsupportedOperationException. + * + * @return set of entries contained in this map. + */ + Set<Entry<K, Versioned<V>>> entrySet(); + + /** + * If the specified key is not already associated with a value + * associates it with the given value and returns null, else returns the current value. + * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @return the previous value associated with the specified key or null + * if key does not already mapped to a value. + */ + Versioned<V> putIfAbsent(K key, V value); + + /** + * Removes the entry for the specified key only if it is currently + * mapped to the specified value. + * + * @param key key with which the specified value is associated + * @param value value expected to be associated with the specified key + * @return true if the value was removed + */ + boolean remove(K key, V value); + + /** + * Removes the entry for the specified key only if its current + * version in the map is equal to the specified version. + * + * @param key key with which the specified version is associated + * @param version version expected to be associated with the specified key + * @return true if the value was removed + */ + boolean remove(K key, long version); + + /** + * Replaces the entry for the specified key only if currently mapped + * to the specified value. + * + * @param key key with which the specified value is associated + * @param oldValue value expected to be associated with the specified key + * @param newValue value to be associated with the specified key + * @return true if the value was replaced + */ + boolean replace(K key, V oldValue, V newValue); + + /** + * Replaces the entry for the specified key only if it is currently mapped to the + * specified version. + * + * @param key key key with which the specified value is associated + * @param oldVersion version expected to be associated with the specified key + * @param newValue value to be associated with the specified key + * @return true if the value was replaced + */ + boolean replace(K key, long oldVersion, V newValue); + + /** + * Registers the specified listener to be notified whenever the map is updated. + * + * @param listener listener to notify about map events + */ + void addListener(MapEventListener<K, V> listener); + + /** + * Unregisters the specified listener such that it will no longer + * receive map change notifications. + * + * @param listener listener to unregister + */ + void removeListener(MapEventListener<K, V> listener); + + /** + * Returns a java.util.Map instance backed by this ConsistentMap. + * @return java.util.Map + */ + Map<K, V> asJavaMap(); +}
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