org.apache.flink.api.common.state

类 StateDescriptor<S extends State,T>

java.lang.Object

org.apache.flink.api.common.state.StateDescriptor<S,T>

类型参数:

S - The type of the State objects created from this StateDescriptor.

T - The type of the value of the state object described by this state descriptor.

所有已实现的接口:

Serializable

直接已知子类:

AggregatingStateDescriptor, ListStateDescriptor, MapStateDescriptor, ReducingStateDescriptor, ValueStateDescriptor

@PublicEvolving
public abstract class StateDescriptor<S extends State,T>
extends Object
implements Serializable

Base class for state descriptors. A StateDescriptor is used for creating partitioned State in stateful operations.

Subclasses must correctly implement equals(Object) and hashCode().

另请参阅:

序列化表格

嵌套类概要

嵌套类

限定符和类型	类和说明
static class	StateDescriptor.Type An enumeration of the types of supported states.

字段概要

字段

限定符和类型	字段和说明
protected T	defaultValue 已过时。 To make the semantics more clear, user should manually manage the default value if the contents of the state is null
protected String	name Name that uniquely identifies state created from this StateDescriptor.

构造器概要

构造器

限定符	构造器和说明
protected	StateDescriptor(String name, Class<T> type, T defaultValue) Create a new StateDescriptor with the given name and the given type information.
protected	StateDescriptor(String name, TypeInformation<T> typeInfo, T defaultValue) Create a new StateDescriptor with the given name and the given type information.
protected	StateDescriptor(String name, TypeSerializer<T> serializer, T defaultValue) Create a new StateDescriptor with the given name and the given type serializer.

方法概要

限定符和类型	方法和说明
void	enableTimeToLive(StateTtlConfig ttlConfig) Configures optional activation of state time-to-live (TTL).
boolean	equals(Object o)
T	getDefaultValue() Returns the default value.
String	getName() Returns the name of this StateDescriptor.
String	getQueryableStateName() Returns the queryable state name.
TypeSerializer<T>	getSerializer() Returns the TypeSerializer that can be used to serialize the value in the state.
StateTtlConfig	getTtlConfig()
abstract StateDescriptor.Type	getType()
int	hashCode()
void	initializeSerializerUnlessSet(ExecutionConfig executionConfig) Initializes the serializer, unless it has been initialized before.
boolean	isQueryable() Returns whether the state created from this descriptor is queryable.
boolean	isSerializerInitialized() Checks whether the serializer has been initialized.
void	setQueryable(String queryableStateName) Sets the name for queries of state created from this descriptor.
String	toString()

从类继承的方法 java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

字段详细资料

name

protected final String name

Name that uniquely identifies state created from this StateDescriptor.

defaultValue

@Nullable
 @Deprecated
protected transient T defaultValue

已过时。 To make the semantics more clear, user should manually manage the default value if the contents of the state is null

The default value returned by the state when no other value is bound to a key.

构造器详细资料

StateDescriptor

protected StateDescriptor(String name,
                          TypeSerializer<T> serializer,
                          @Nullable
                          T defaultValue)

Create a new StateDescriptor with the given name and the given type serializer.

参数:

name - The name of the StateDescriptor.

serializer - The type serializer for the values in the state.

defaultValue - The default value that will be set when requesting state without setting a value before.

StateDescriptor

protected StateDescriptor(String name,
                          TypeInformation<T> typeInfo,
                          @Nullable
                          T defaultValue)

Create a new StateDescriptor with the given name and the given type information.

参数:

name - The name of the StateDescriptor.

typeInfo - The type information for the values in the state.

defaultValue - The default value that will be set when requesting state without setting a value before.

StateDescriptor

protected StateDescriptor(String name,
                          Class<T> type,
                          @Nullable
                          T defaultValue)

Create a new StateDescriptor with the given name and the given type information.

If this constructor fails (because it is not possible to describe the type via a class), consider using the StateDescriptor(String, TypeInformation, Object) constructor.

参数:

name - The name of the StateDescriptor.

type - The class of the type of values in the state.

defaultValue - The default value that will be set when requesting state without setting a value before.

方法详细资料

getName

public String getName()

Returns the name of this StateDescriptor.

getDefaultValue

public T getDefaultValue()

Returns the default value.

getSerializer

public TypeSerializer<T> getSerializer()

Returns the TypeSerializer that can be used to serialize the value in the state. Note that the serializer may initialized lazily and is only guaranteed to exist after calling initializeSerializerUnlessSet(ExecutionConfig).

setQueryable

public void setQueryable(String queryableStateName)

Sets the name for queries of state created from this descriptor.

If a name is set, the created state will be published for queries during runtime. The name needs to be unique per job. If there is another state instance published under the same name, the job will fail during runtime.

参数:

queryableStateName - State name for queries (unique name per job)

抛出:

IllegalStateException - If queryable state name already set

getQueryableStateName

@Nullable
public String getQueryableStateName()

Returns the queryable state name.

返回:

Queryable state name or null if not set.

isQueryable

public boolean isQueryable()

Returns whether the state created from this descriptor is queryable.

返回:

true if state is queryable, false otherwise.

enableTimeToLive

public void enableTimeToLive(StateTtlConfig ttlConfig)

Configures optional activation of state time-to-live (TTL).

State user value will expire, become unavailable and be cleaned up in storage depending on configured StateTtlConfig.

If enabling the TTL configuration, the field defaultValue will be invalid.

参数:

ttlConfig - configuration of state TTL

getTtlConfig

@Nonnull
 @Internal
public StateTtlConfig getTtlConfig()

isSerializerInitialized

public boolean isSerializerInitialized()

Checks whether the serializer has been initialized. Serializer initialization is lazy, to allow parametrization of serializers with an ExecutionConfig via initializeSerializerUnlessSet(ExecutionConfig).

返回:

True if the serializers have been initialized, false otherwise.

initializeSerializerUnlessSet

public void initializeSerializerUnlessSet(ExecutionConfig executionConfig)

Initializes the serializer, unless it has been initialized before.

参数:

executionConfig - The execution config to use when creating the serializer.

hashCode

public final int hashCode()

覆盖:

hashCode 在类中 Object

equals

public final boolean equals(Object o)

覆盖:

equals 在类中 Object

toString

public String toString()

覆盖:

toString 在类中 Object

getType

public abstract StateDescriptor.Type getType()