org.apache.flink.runtime.state

类 ChainedStateHandle<T extends StateObject>

java.lang.Object

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

所有已实现的接口:

Serializable, StateObject

public class ChainedStateHandle<T extends StateObject>
extends Object
implements StateObject

Handle to state handles for the operators in an operator chain.

另请参阅:

序列化表格

构造器概要

构造器

构造器和说明
ChainedStateHandle(List<? extends T> operatorStateHandles) Wraps a list to the state handles for the operators in a chain.

方法概要

限定符和类型	方法和说明
void	discardState() Discards the state referred to and solemnly owned by this handle, to free up resources in the persistent storage.
boolean	equals(Object o)
T	get(int index) Get the state handle for a single operator in the operator chain by it's index.
int	getLength() Returns the length of the operator chain.
long	getStateSize() Returns the size of the state in bytes.
int	hashCode()
boolean	isEmpty() Check if there are any states handles present.
static boolean	isNullOrEmpty(ChainedStateHandle<?> chainedStateHandle)
static <T extends StateObject> ChainedStateHandle<T>	wrapSingleHandle(T stateHandleToWrap)

从类继承的方法 java.lang.Object

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

构造器详细资料

ChainedStateHandle

public ChainedStateHandle(List<? extends T> operatorStateHandles)

Wraps a list to the state handles for the operators in a chain. Individual state handles can be null.

参数:

operatorStateHandles - list with the state handles for the states in the operator chain.

方法详细资料

isEmpty

public boolean isEmpty()

Check if there are any states handles present. Notice that this can be true even if getLength() is greater than zero, because state handles can be null.

返回:

true if there are no state handles for any operator.

getLength

public int getLength()

Returns the length of the operator chain. This can be different from the number of operator state handles, because the some operators in the chain can have no state and thus their state handle can be null.

返回:

length of the operator chain

get

public T get(int index)

Get the state handle for a single operator in the operator chain by it's index.

参数:

index - the index in the operator chain

返回:

state handle to the operator at the given position in the operator chain. can be null.

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.

equals

public boolean equals(Object o)

覆盖:

equals 在类中 Object

hashCode

public int hashCode()

覆盖:

hashCode 在类中 Object

wrapSingleHandle

public static <T extends StateObject> ChainedStateHandle<T> wrapSingleHandle(T stateHandleToWrap)

isNullOrEmpty

public static boolean isNullOrEmpty(ChainedStateHandle<?> chainedStateHandle)