Package com.hazelcast.replicatedmap

Interface ReplicatedMap<K,V>

Type Parameters:
K - the type of keys maintained by this map
V - the type of mapped values
All Superinterfaces:
DistributedObject, Map<K,V>
public interface ReplicatedMap<K,V> extends Map<K,V>, DistributedObject

A ReplicatedMap is a map data structure with weak consistency and has entries stored locally on every node of the cluster.

Whenever a value is written, the new value will be internally distributed to all existing cluster members, and eventually every node will have the new value. Reading is always local on members (except for lite members).

When a new node joins the cluster, it initially requests existing values from older nodes and replicates them locally.

Supports split-brain protection in cluster versions 3.10 and higher.

Since:
3.2

  • Method Details

    • put

      V put(@Nonnull K key, @Nonnull V value, long ttl, @Nonnull TimeUnit timeUnit)

      Associates a given value to the specified key and replicates it to the cluster. If there is an old value, it will be replaced by the specified one and returned from the call.

      In addition, you have to specify a ttl and its TimeUnit to define when the value is outdated and thus should be removed from the replicated map.

      Parameters:
      key - key with which the specified value is to be associated.
      value - value to be associated with the specified key.
      ttl - ttl to be associated with the specified key-value pair.
      timeUnit - TimeUnit to be used for the ttl value.

    • clear

      void clear()

      The clear operation wipes data out of the replicated maps.

      If some node fails on executing the operation, it is retried for at most 5 times (on the failing nodes only).

      Specified by:
      clear in interface Map<K,V>

    • removeEntryListener

      boolean removeEntryListener(@Nonnull UUID id)
      Removes the specified entry listener. Returns silently if there was no such listener added before.
      Parameters:
      id - ID of the registered entry listener.
      Returns:
      true if registration is removed, false otherwise.

    • addEntryListener

      @Nonnull UUID addEntryListener(@Nonnull EntryListener<K,V> listener)
      Adds an entry listener for this map. The listener will be notified for all map add/remove/update/evict events.
      Parameters:
      listener - entry listener

    • addEntryListener

      @Nonnull UUID addEntryListener(@Nonnull EntryListener<K,V> listener, @Nullable K key)
      Adds the specified entry listener for the specified key. The listener will be notified for all add/remove/update/evict events of the specified key only.

      Warning: This method uses hashCode and equals of the binary form of the key, not the actual implementations of hashCode and equals defined in the key's class.

      Parameters:
      listener - the entry listener to add
      key - the key to listen to
      Throws:
      NullPointerException - if the specified key is null

    • addEntryListener

      @Nonnull UUID addEntryListener(@Nonnull EntryListener<K,V> listener, @Nonnull Predicate<K,V> predicate)
      Adds a continuous entry listener for this map. The listener will be notified for map add/remove/update/evict events filtered by the given predicate.
      Parameters:
      listener - the entry listener to add
      predicate - the predicate for filtering entries

    • addEntryListener

      @Nonnull UUID addEntryListener(@Nonnull EntryListener<K,V> listener, @Nonnull Predicate<K,V> predicate, @Nullable K key)
      Adds a continuous entry listener for this map. The listener will be notified for map add/remove/update/evict events filtered by the given predicate.
      Parameters:
      listener - the entry listener
      predicate - the predicate for filtering entries
      key - the key to listen to

    • values

      @Nonnull Collection<V> values()
      Returns a lazy Collection view of the values contained in this map.
      A LazyCollection is optimized for querying speed (preventing eager deserialization and hashing on HashSet insertion) and does NOT provide all operations. Any kind of mutating function will throw an UnsupportedOperationException. Same is true for operations like Collection.contains(Object) and Collection.containsAll(Collection), which would result in very poor performance if called repeatedly (for example, in a loop). If the use case is different from querying the data, please copy the resulting set into a new List or similar data structure. 
           ReplicatedMap<K, V> repMap = ...;
     // Returns a LazyCollection
     Collection<V> values = repMap.values();
     List<V> copy = new ArrayList<V>(values);
     if (copy.containsAll(possibleValues)) {
         // ...
     }
      Due to the lazy nature of the returned set, changes to the map (addition, removal, update) might be reflected on the collection.
      Changes on the map are NOT reflected on the collection on the CLIENT or vice versa. The order of the elements is not guaranteed due to the internal asynchronous replication behavior. If a specific order is needed, use values(Comparator) to force reordering of the elements before returning.
      Changes to any returned object are NOT replicated back to other members.
      Specified by:
      values in interface Map<K,V>
      Returns:
      A collection view of the values contained in this map.

    • values

      @Nonnull Collection<V> values(@Nullable Comparator<V> comparator)
      Returns an eagerly populated Collection view of the values contained in this map. The collection is NOT backed by the map, so changes to the map are NOT reflected on the collection, and vice-versa.
      The order of the elements is guaranteed by executing the given Comparator before returning the elements.
      Changes to any returned object are NOT replicated back to other members.
      Parameters:
      comparator - the Comparator to sort the returned elements.
      Returns:
      An eagerly populated Collection view of the values contained in this map.

    • entrySet

      @Nonnull Set<Map.Entry<K,V>> entrySet()
      Returns a lazy Set view of the mappings contained in this map.
      A LazySet is optimized for querying speed (preventing eager deserialization and hashing on HashSet insertion) and does NOT provide all operations. Any kind of mutating function will throw an UnsupportedOperationException. Same is true for operations like Set.contains(Object) and Set.containsAll(Collection) which would result in very poor performance if called repeatedly (for example, in a loop). If the use case is different from querying the data, please copy the resulting set into a new HashSet. 
           ReplicatedMap<K, V> repMap = ...;
     // Returns a LazySet
     Set<Map.Entry<K, V>> entrySet = repMap.entrySet();
     Set<Map.Entry<K, V>> copy = new HashSet<Map.Entry<K, V>>(entrySet);
      Due to the lazy nature of the returned set, changes to the map (addition, removal, update) might be reflected on the set.
      Changes on the map are NOT reflected on the set on the CLIENT or vice versa. The order of the elements is not guaranteed due to the internal asynchronous replication behavior.
      Changes to any returned object are NOT replicated back to other members.
      Specified by:
      entrySet in interface Map<K,V>
      Returns:
      A lazy set view of the mappings contained in this map.

    • keySet

      @Nonnull Set<K> keySet()
      Returns a lazy Set view of the key contained in this map.
      A LazySet is optimized for querying speed (preventing eager deserialization and hashing on HashSet insertion) and does NOT provide all operations. Any kind of mutating function will throw an UnsupportedOperationException. Same is true for operations like Set.contains(Object) and Set.containsAll(Collection) which would result in very poor performance if called repeatedly (for example, in a loop). If the use case is different from querying the data, please copy the resulting set into a new HashSet. 
           ReplicatedMap<K, V> repMap = ...;
     // Returns a LazySet
     Set<K> keySet = repMap.keySet();
     Set<K> copy = new HashSet<K>(keySet);
     for (K key : possibleKeys) {
       if (!copy.contains(key))
         return false;
     }

      Due to the lazy nature of the returned set, changes to the map (addition, removal, update) might be reflected on the set.
      Changes on the map are NOT reflected on the set on the CLIENT or vice versa. The order of the elements is not guaranteed due to the internal asynchronous replication behavior.
      Changes to any returned object are NOT replicated back to other members.

      Specified by:
      keySet in interface Map<K,V>
      Returns:
      A lazy Set view of the keys contained in this map.