org.apache.nifi.distributed.cache.client

Interface DistributedMapCacheClient

All Superinterfaces:

ConfigurableComponent, ControllerService

All Known Subinterfaces:

AtomicDistributedMapCacheClient<R>

@Tags(value={"distributed","client","cluster","map","cache"})
 @CapabilityDescription(value="Provides the ability to communicate with a DistributedMapCacheServer. This allows multiple nodes to coordinate state with a single remote entity.")
public interface DistributedMapCacheClient
extends ControllerService

This interface defines an API that can be used for interacting with a Distributed Cache that functions similarly to a Map.

Method Summary

Modifier and Type	Method and Description
void	close() Attempts to notify the server that we are finished communicating with it and cleans up resources
<K> boolean	containsKey(K key, Serializer<K> keySerializer) Determines if the given value is present in the cache and if so returns true, else returns false
<K,V> V	get(K key, Serializer<K> keySerializer, Deserializer<V> valueDeserializer) Returns the value in the cache for the given key, if one exists; otherwise returns null
<K,V> V	getAndPutIfAbsent(K key, V value, Serializer<K> keySerializer, Serializer<V> valueSerializer, Deserializer<V> valueDeserializer) Adds the specified key and value to the cache, if they are not already present, serializing the key and value with the given Serializers.
default <K> Set<K>	keySet(Deserializer<K> keyDeserializer) Returns a set of all keys currently in the cache
<K,V> void	put(K key, V value, Serializer<K> keySerializer, Serializer<V> valueSerializer) Adds the specified key and value to the cache, overwriting any value that is currently set.
default <K,V> void	putAll(Map<K,V> keysAndValues, Serializer<K> keySerializer, Serializer<V> valueSerializer) Performs a bulk put operation.
<K,V> boolean	putIfAbsent(K key, V value, Serializer<K> keySerializer, Serializer<V> valueSerializer) Adds the specified key and value to the cache, if they are not already present, serializing the key and value with the given Serializers.
<K> boolean	remove(K key, Serializer<K> serializer) Removes the entry with the given key from the cache, if it is present.
default <K,V> V	removeAndGet(K key, Serializer<K> keySerializer, Deserializer<V> valueDeserializer) Removes the entry with the given key from the cache, if it is present, and returns the value that was removed from the map.
long	removeByPattern(String regex) Removes entries whose keys match the specified pattern
default <K,V> Map<K,V>	removeByPatternAndGet(String regex, Deserializer<K> keyDeserializer, Deserializer<V> valueDeserializer) Removes entries whose keys match the specified pattern, and returns a map of entries that were removed.
default <K,V> Map<K,V>	subMap(Set<K> keys, Serializer<K> keySerializer, Deserializer<V> valueDeserializer) Returns the values in the cache for the given keys, if they exist; otherwise returns null

Methods inherited from interface org.apache.nifi.controller.ControllerService

initialize

Methods inherited from interface org.apache.nifi.components.ConfigurableComponent

getIdentifier, getPropertyDescriptor, getPropertyDescriptors, onPropertyModified, validate

Method Detail

putIfAbsent

<K,V> boolean putIfAbsent(K key,
                          V value,
                          Serializer<K> keySerializer,
                          Serializer<V> valueSerializer)
                   throws IOException

Adds the specified key and value to the cache, if they are not already present, serializing the key and value with the given Serializers.

Type Parameters:

K - type of key

V - type of value

Parameters:

key - the key for into the map

value - the value to add to the map if and only if the key is absent

keySerializer - key serializer

valueSerializer - value serializer

Returns:

true if the value was added to the cache, false if the value already existed in the cache

Throws:

IOException - if unable to communicate with the remote instance

getAndPutIfAbsent

<K,V> V getAndPutIfAbsent(K key,
                          V value,
                          Serializer<K> keySerializer,
                          Serializer<V> valueSerializer,
                          Deserializer<V> valueDeserializer)
                   throws IOException

Adds the specified key and value to the cache, if they are not already present, serializing the key and value with the given Serializers. If a value already exists in the cache for the given key, the value associated with the key is returned, after being deserialized with the given valueDeserializer.

Type Parameters:

K - type of key

V - type of value

Parameters:

key - key

value - value

keySerializer - key serializer

valueSerializer - key serializer

valueDeserializer - value deserializer

Returns:

If a value already exists in the cache for the given key, the value associated with the key is returned, after being deserialized with the given valueDeserializer. If the key does not exist, the key and its value will be added to the cache.

Throws:

IOException - ex

containsKey

<K> boolean containsKey(K key,
                        Serializer<K> keySerializer)
                 throws IOException

Determines if the given value is present in the cache and if so returns true, else returns false

Type Parameters:

K - type of key

Parameters:

key - key

keySerializer - key serializer

Returns:

Determines if the given value is present in the cache and if so returns true, else returns false

Throws:

IOException - if unable to communicate with the remote instance

put

<K,V> void put(K key,
               V value,
               Serializer<K> keySerializer,
               Serializer<V> valueSerializer)
        throws IOException

Adds the specified key and value to the cache, overwriting any value that is currently set.

Type Parameters:

K - the key type

V - the value type

Parameters:

key - The key to set

value - The value to associate with the given Key

keySerializer - the Serializer that will be used to serialize the key into bytes

valueSerializer - the Serializer that will be used to serialize the value into bytes

Throws:

IOException - if unable to communicate with the remote instance

NullPointerException - if the key or either serializer is null

putAll

default <K,V> void putAll(Map<K,V> keysAndValues,
                          Serializer<K> keySerializer,
                          Serializer<V> valueSerializer)
                   throws IOException

Performs a bulk put operation. This should be used when needed to send a large batch of updates to a cache in a single update operation.

Type Parameters:

K - The key type

V - The value type

Parameters:

keysAndValues - A java.util.Map that contains an association between keys and values to be bulk inserted into the cache.

keySerializer - The Serializer that will be used to serialize the key into bytes

valueSerializer - The Serializer that will be used to serialize the value into bytes

Throws:

IOException - if unable to communicate with the remote instance

get

<K,V> V get(K key,
            Serializer<K> keySerializer,
            Deserializer<V> valueDeserializer)
     throws IOException

Returns the value in the cache for the given key, if one exists; otherwise returns null

Type Parameters:

K - the key type

V - the value type

Parameters:

key - the key to lookup in the map

keySerializer - key serializer

valueDeserializer - value serializer

Returns:

the value in the cache for the given key, if one exists; otherwise returns null

Throws:

IOException - ex

subMap

default <K,V> Map<K,V> subMap(Set<K> keys,
                              Serializer<K> keySerializer,
                              Deserializer<V> valueDeserializer)
                       throws IOException

Returns the values in the cache for the given keys, if they exist; otherwise returns null

Type Parameters:

K - the key type

V - the value type

Parameters:

keys - a set of keys whose values to lookup in the map

keySerializer - key serializer

valueDeserializer - value serializer

Returns:

the value in the cache for the given key, if one exists; otherwise returns null

Throws:

IOException - ex

close

void close()
    throws IOException

Attempts to notify the server that we are finished communicating with it and cleans up resources

Throws:

IOException - ex

remove

<K> boolean remove(K key,
                   Serializer<K> serializer)
            throws IOException

Removes the entry with the given key from the cache, if it is present.

Type Parameters:

K - type of key

Parameters:

key - key

serializer - serializer

Returns:

true if the entry is removed, false if the key did not exist in the cache

Throws:

IOException - ex

removeAndGet

default <K,V> V removeAndGet(K key,
                             Serializer<K> keySerializer,
                             Deserializer<V> valueDeserializer)
                      throws IOException

Removes the entry with the given key from the cache, if it is present, and returns the value that was removed from the map.

Type Parameters:

K - type of key

V - type of value

Parameters:

key - key

keySerializer - key serializer

valueDeserializer - value deserializer

Returns:

the value previously associated with the key, or null if there was no mapping null can also indicate that the map previously associated null with the key

Throws:

IOException - ex

removeByPattern

long removeByPattern(String regex)
              throws IOException

Removes entries whose keys match the specified pattern

Parameters:

regex - The regular expression / pattern on which to match the keys to be removed

Returns:

The number of entries that were removed

Throws:

IOException - if any error occurred while removing an entry

removeByPatternAndGet

default <K,V> Map<K,V> removeByPatternAndGet(String regex,
                                             Deserializer<K> keyDeserializer,
                                             Deserializer<V> valueDeserializer)
                                      throws IOException

Removes entries whose keys match the specified pattern, and returns a map of entries that were removed.

Type Parameters:

K - type of key

V - type of value

Parameters:

regex - The regular expression / pattern on which to match the keys to be removed

keyDeserializer - key deserializer

valueDeserializer - value deserializer

Returns:

A map of key/value entries that were removed from the cache

Throws:

IOException - if any error occurred while removing an entry

keySet

default <K> Set<K> keySet(Deserializer<K> keyDeserializer)
                   throws IOException

Returns a set of all keys currently in the cache

Type Parameters:

K - type of key

Parameters:

keyDeserializer - key deserializer

Returns:

a Set of all keys currently in the cache

Throws:

IOException - ex