public class ChainedStateHandle<T extends StateObject> extends Object implements StateObject
Constructor and Description |
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ChainedStateHandle(List<? extends T> operatorStateHandles)
Wraps a list to the state handles for the operators in a chain.
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Modifier and Type | Method and Description |
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void |
discardState()
Discards the state referred to by this handle, to free up resources in
the persistent storage.
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boolean |
equals(Object o) |
T |
get(int index)
Get the state handle for a single operator in the operator chain by it's index.
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int |
getLength()
Returns the length of the operator chain.
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long |
getStateSize()
Returns the size of the state in bytes.
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int |
hashCode() |
boolean |
isEmpty()
Check if there are any states handles present.
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static boolean |
isNullOrEmpty(ChainedStateHandle<?> chainedStateHandle) |
static <T extends StateObject> |
wrapSingleHandle(T stateHandleToWrap) |
public boolean isEmpty()
getLength()
is
greater than zero, because state handles can be null.public int getLength()
public T get(int index)
index
- the index in the operator chainpublic void discardState() throws Exception
StateObject
discardState
in interface StateObject
Exception
public long getStateSize()
StateObject
If the the size is not known, return 0
.
getStateSize
in interface StateObject
public static <T extends StateObject> ChainedStateHandle<T> wrapSingleHandle(T stateHandleToWrap)
public static boolean isNullOrEmpty(ChainedStateHandle<?> chainedStateHandle)
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