io.vertx.core.shareddata.LocalMap Maven / Gradle / Ivy
/*
* Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
* http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
* which is available at https://www.apache.org/licenses/LICENSE-2.0.
*
* SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
*/
package io.vertx.core.shareddata;
import io.vertx.codegen.annotations.GenIgnore;
import io.vertx.codegen.annotations.VertxGen;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import java.util.function.BiConsumer;
import java.util.function.BiFunction;
import java.util.function.Function;
/**
* Local maps can be used to share data safely in a single Vert.x instance.
*
* By default the map allows immutable keys and values.
* Custom keys and values should implement {@link Shareable} interface. The map returns their copies.
*
* This ensures there is no shared access to mutable state from different threads (e.g. different event loops) in the
* Vert.x instance, and means you don't have to protect access to that state using synchronization or locks.
*
*
* Since the version 3.4, this class extends the {@link Map} interface. However some methods are only accessible in Java.
*
* @author Tim Fox
* @see Shareable
*/
@VertxGen
public interface LocalMap extends Map {
/**
* Get a value from the map
*
* @param key the key
* @return the value, or null if none
*/
V get(Object key);
/**
* Put an entry in the map
*
* @param key the key
* @param value the value
* @return return the old value, or null if none
*/
V put(K key, V value);
/**
* Remove an entry from the map
*
* @param key the key
* @return the old value
*/
V remove(Object key);
/**
* Clear all entries in the map
*/
void clear();
/**
* Get the size of the map
*
* @return the number of entries in the map
*/
int size();
/**
* @return true if there are zero entries in the map
*/
boolean isEmpty();
/**
* Put the entry only if there is no existing entry for that key
*
* @param key the key
* @param value the value
* @return the old value or null, if none
*/
V putIfAbsent(K key, V value);
/**
* Remove the entry only if there is an entry with the specified key and value.
*
* This method is the poyglot version of {@link #remove(Object, Object)}.
*
* @param key the key
* @param value the value
* @return true if removed
*/
boolean removeIfPresent(K key, V value);
/**
* Replace the entry only if there is an existing entry with the specified key and value.
*
* This method is the polyglot version of {@link #replace(Object, Object, Object)}.
*
* @param key the key
* @param oldValue the old value
* @param newValue the new value
* @return true if removed
*/
boolean replaceIfPresent(K key, V oldValue, V newValue);
/**
* Replace the entry only if there is an existing entry with the key
*
* @param key the key
* @param value the new value
* @return the old value
*/
V replace(K key, V value);
/**
* Close and release the map
*/
void close();
/**
* @return the set of keys in the map
*/
@GenIgnore
Set keySet();
/**
* @return the set of values in the map
*/
@GenIgnore
Collection values();
/**
* Attempts to compute a mapping for the specified key and its current
* mapped value (or {@code null} if there is no current mapping).
*
* If the function returns {@code null}, the mapping is removed (or
* remains absent if initially absent). If the function itself throws an
* (unchecked) exception, the exception is rethrown, and the current mapping
* is left unchanged.
*
* @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
**/
@GenIgnore
@Override
V compute(K key, BiFunction remappingFunction);
/**
* If the specified key is not already associated with a value (or is mapped
* to {@code null}), attempts to compute its value using the given mapping
* function and enters it into this map unless {@code null}.
*
* If the function returns {@code null} no mapping is recorded. If
* the function itself throws an (unchecked) exception, the
* exception is rethrown, and no mapping is recorded.
*
* @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
*/
@GenIgnore
@Override
V computeIfAbsent(K key, Function mappingFunction);
/**
* 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 function returns {@code null}, the mapping is removed. If the
* function itself throws an (unchecked) exception, the exception is
* rethrown, and the current mapping is left unchanged.
*
* @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
*/
@GenIgnore
@Override
V computeIfPresent(K key, BiFunction remappingFunction);
/**
* Returns {@code true} if this map contains a mapping for the specified
* key.
*
* @param key key whose presence in this map is to be tested
* @return {@code true} if this map contains a mapping for the specified key
*/
@Override
boolean containsKey(Object key);
/**
* Returns @{code true} if this map maps one or more keys to the
* specified value.
*
* @param value value whose presence in this map is to be tested
* @return @{code true} if this map maps one or more keys to the specified value
*/
@Override
boolean containsValue(Object value);
/**
* Returns a {@link Set} view of the mappings contained in this map.
*
* Unlike the default {@link Map} implementation, the set is not backed by the map. So changes
* made to the map are not reflected in the set. Entries added or remove to the set are not reflected to the map.
* In addition, the entries are not modifiable ({@link java.util.Map.Entry#setValue(Object)} is not supported).
*
* @return a set view of the mappings contained in this map
*/
@GenIgnore
@Override
Set> entrySet();
/**
* Performs the given action for each entry in this map until all entries
* have been processed or the action throws an exception.
*
* Exceptions thrown by the action are relayed to the caller.
*
* @param action The action to be performed for each entry
*/
@GenIgnore
@Override
void forEach(BiConsumer action);
/**
* Returns the value to which the specified key is mapped, or
* {@code defaultValue} if this map contains no mapping for the key.
*
* @param key the key whose associated value is to be returned
* @param defaultValue the default mapping of the key
* @return the value to which the specified key is mapped, or {@code defaultValue} if this map contains no mapping
* for the key
*/
@Override
V getOrDefault(Object key, V defaultValue);
/**
* If the specified key is not already associated with a value or is
* associated with null, associates it with the given non-null value.
* Otherwise, replaces the associated value with the results of the given
* remapping function, or removes if the result is {@code null}. This
* method may be of use when combining multiple mapped values for a key.
*
* @param key key with which the resulting value is to be associated
* @param value the non-null value to be merged with the existing value
* associated with the key or, if no existing value or a null value
* is associated with the key, to be associated with the key
* @param remappingFunction the function to recompute a value if present
* @return the new value associated with the specified key, or null if no
* value is associated with the key
*/
@GenIgnore
@Override
V merge(K key, V value, BiFunction remappingFunction);
/**
* Copies all of the mappings from the specified map to this map. The effect of this call is equivalent to that
* of calling {@link #put(Object, Object) put(k, v)} on this map once for each mapping from key {@code k} to value
* {@code v} in the specified map. The behavior of this operation is undefined if the specified map is modified
* while the operation is in progress.
*
* @param m mappings to be stored in this map
*/
@GenIgnore
@Override
void putAll(Map m);
/**
* 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 {@code true} if the value was removed
*/
@Override
@GenIgnore
boolean remove(Object key, Object value);
/**
* 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 {@code true} if the value was replaced
*/
@Override
@GenIgnore
boolean replace(K key, V oldValue, V newValue);
/**
* Replaces each entry's value with the result of invoking the given
* function on that entry until all entries have been processed or the
* function throws an exception. Exceptions thrown by the function are
* relayed to the caller.
*
* @param function the function to apply to each entry
*/
@GenIgnore
@Override
void replaceAll(BiFunction function);
}