org.apache.nifi.distributed.cache.client

Interface DistributedMapCacheClient

All Superinterfaces:

ConfigurableComponent, ControllerService

@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.
<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.
<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.

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

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

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

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