org.apache.flink.runtime.state.subkeyed.SubKeyedState Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.flink.runtime.state.subkeyed;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.state.StateStorage;
import java.util.Iterator;
import java.util.Map;
/**
* Base interface for all subkeyed states.
*
* @param The type of the keys in the state.
* @param The type of the namespaces in the state.
* @param The type of the values in the state.
*/
public interface SubKeyedState {
/**
* Returns the descriptor of the state.
*
* @return The descriptor of the state.
*/
SubKeyedStateDescriptor getDescriptor();
/**
* Returns true if the state contains a value under the given key and the
* given namespace.
*
* @param key The key under which the value's presence is to be tested.
* @param namespace The namespace of the value to be tested.
* @return True if the state contains a value under the given key and the
* given namespace.
*/
boolean contains(K key, N namespace);
/**
* Returns the value under the given key and namespace in the state.
*
* @param key The key under which the value is to be retrieved.
* @param namespace The namespace of the value to be retrieved.
* @return The value under the given key and namespace in the state.
*/
V get(K key, N namespace);
/**
* Returns the value under the given key and namespace in the state, or
* {@code defaultValue} if there does not exist any value under the key
* and the namespace in the state.
*
* @param key The key under which the value is to be retrieved.
* @param namespace The namespace of the value to be retrieved.
* @param defaultValue The default value under the given key and namespace in the state.
* @return The value under the given key and namespace in the state, or
* {@code defaultValue} if there does not exist any value under the
* key and the namespace in the state.
*/
V getOrDefault(K key, N namespace, V defaultValue);
/**
* Returns the namespaces and their values under the given key in the state.
*
* @param key The key under which the namespaces and values are to be
* retrieved.
* @return The namespaces and their values in the state.
*/
Map getAll(K key);
/**
* Removes the given namespace from the given key in the state, if it is
* present.
*
* @param key The key under which the given namespace is to be removed from.
* @param namespace The namespace to be removed.
*/
void remove(K key, N namespace);
/**
* Removes the given key from the state.
*
* @param key The key of the namespaces to be removed.
*/
void removeAll(K key);
/**
* Return an iterator over the namespaces under the given key.
*
* @param key The key whose namespaces are to be iterated.
* @return An iterator over the namespace under the given key.
*/
Iterator iterator(K key);
/**
* Return all the keys which are in the specified namespace.
*
* @param namespace The namespace which the keys will be retrieved.
*
* @return All the keys associated with the specified namespace.
*/
Iterable keys(N namespace);
/**
* Returns the state storage within this keyed state.
*
* @return The state storage within this keyed state.
*/
StateStorage getStateStorage();
/**
* Returns the serialized value for the given key and namespace.
*
* If no value is associated with key and namespace, null
* is returned.
*
*
TO IMPLEMENTERS: This method is called by multiple threads. Anything
* stateful (e.g. serializers) should be either duplicated or protected from undesired
* consequences of concurrent invocations.
*
* @param serializedKeyAndNamespace Serialized key and namespace
* @param safeKeySerializer A key serializer which is safe to be used even in multi-threaded context
* @param safeNamespaceSerializer A namespace serializer which is safe to be used even in multi-threaded context
* @param safeValueSerializer A value serializer which is safe to be used even in multi-threaded context
* @return Serialized value or null if no value is associated with the key and namespace.
*
* @throws Exception Exceptions during serialization are forwarded
*/
byte[] getSerializedValue(
final byte[] serializedKeyAndNamespace,
final TypeSerializer safeKeySerializer,
final TypeSerializer safeNamespaceSerializer,
final TypeSerializer safeValueSerializer) throws Exception;
}