org.apache.flink.runtime.state

类 RetrievableStreamStateHandle<T extends Serializable>

java.lang.Object

org.apache.flink.runtime.state.RetrievableStreamStateHandle<T>

类型参数:

T - type of the retrievable object which is stored under the wrapped stream handle

所有已实现的接口:

Closeable, Serializable, AutoCloseable, RetrievableStateHandle<T>, StateObject, StreamStateHandle

public class RetrievableStreamStateHandle<T extends Serializable>
extends Object
implements StreamStateHandle, RetrievableStateHandle<T>, Closeable

Wrapper around a StreamStateHandle to make the referenced state object retrievable trough a simple get call. This implementation expects that the object was serialized through default serialization of Java's ObjectOutputStream.

另请参阅:

序列化表格

构造器概要

构造器

构造器和说明
RetrievableStreamStateHandle(org.apache.flink.core.fs.Path filePath, long stateSize)
RetrievableStreamStateHandle(StreamStateHandle streamStateHandle)

方法概要

限定符和类型	方法和说明
Optional<byte[]>	asBytesIfInMemory()
void	close()
void	discardState() Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage.
long	getStateSize() Returns the size of the state in bytes.
org.apache.flink.core.fs.FSDataInputStream	openInputStream() Returns an FSDataInputStream that can be used to read back the data that was previously written to the stream.
T	retrieveState() Retrieves the object that was previously written to state.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

RetrievableStreamStateHandle

public RetrievableStreamStateHandle(StreamStateHandle streamStateHandle)

RetrievableStreamStateHandle

public RetrievableStreamStateHandle(org.apache.flink.core.fs.Path filePath,
                                    long stateSize)

方法详细资料

retrieveState

public T retrieveState()
                throws IOException,
                       ClassNotFoundException

从接口复制的说明: RetrievableStateHandle

Retrieves the object that was previously written to state.

指定者:

retrieveState 在接口中 RetrievableStateHandle<T extends Serializable>

抛出:

IOException

ClassNotFoundException

openInputStream

public org.apache.flink.core.fs.FSDataInputStream openInputStream()
                                                           throws IOException

从接口复制的说明: StreamStateHandle

Returns an FSDataInputStream that can be used to read back the data that was previously written to the stream.

指定者:

openInputStream 在接口中 StreamStateHandle

抛出:

IOException

asBytesIfInMemory

public Optional<byte[]> asBytesIfInMemory()

指定者:

asBytesIfInMemory 在接口中 StreamStateHandle

返回:

Content of this handle as bytes array if it is already in memory.

discardState

public void discardState()
                  throws Exception

从接口复制的说明: StateObject

Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage. This method is called when the state represented by this object will not be used any more.

指定者:

discardState 在接口中 StateObject

抛出:

Exception

getStateSize

public long getStateSize()

从接口复制的说明: StateObject

Returns the size of the state in bytes. If the size is not known, this method should return 0.

The values produced by this method are only used for informational purposes and for metrics/monitoring. If this method returns wrong values, the checkpoints and recovery will still behave correctly. However, efficiency may be impacted (wrong space pre-allocation) and functionality that depends on metrics (like monitoring) will be impacted.

Note for implementors: This method should not perform any I/O operations while obtaining the state size (hence it does not declare throwing an IOException). Instead, the state size should be stored in the state object, or should be computable from the state stored in this object. The reason is that this method is called frequently by several parts of the checkpointing and issuing I/O requests from this method accumulates a heavy I/O load on the storage system at higher scale.

指定者:

getStateSize 在接口中 StateObject

返回:

Size of the state in bytes.

close

public void close()
           throws IOException

指定者:

close 在接口中 Closeable

指定者:

close 在接口中 AutoCloseable

抛出:

IOException