java.lang.Object
- org.springframework.batch.item.ItemStreamSupport
- - org.springframework.batch.jsr.item.CheckpointSupport

All Implemented Interfaces:
ItemStream
Direct Known Subclasses:
ItemReaderAdapter, ItemWriterAdapter
```
public abstract class CheckpointSupport
extends ItemStreamSupport
```
Provides support for JSR-352 checkpointing. Checkpoint objects are copied prior to being added to the ExecutionContext for persistence by the framework. If the checkpoint object cannot be copied and further changes occur to the same instance, side effects may occur. In cases like this, it is recommended that a copy of the object being acted upon in the reader/writer is returned via the ItemReader.checkpointInfo() or ItemWriter.checkpointInfo() calls.
Since:
3.0
Author:
Michael Minella

Constructor Summary
Constructors
Constructor Description
CheckpointSupport(java.lang.String checkpointKey)

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`close()`	No-op.
`protected abstract java.io.Serializable`	`doCheckpoint()`	Used to provide a `Serializable` representing the current state of the batch artifact.
`protected abstract void`	`doClose()`	Used to close the underlying batch artifact
`protected abstract void`	`doOpen(java.io.Serializable checkpoint)`	Used to open a batch artifact with previously saved checkpoint information.
`void`	`open(ExecutionContext executionContext)`	No-op.
`void`	`update(ExecutionContext executionContext)`	Return empty `ExecutionContext`.

Methods inherited from class org.springframework.batch.item.ItemStreamSupport
getExecutionContextKey, setExecutionContextName, setName

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CheckpointSupport
```
public CheckpointSupport(java.lang.String checkpointKey)
```
    Parameters:
    checkpointKey - key to store the checkpoint object with in the ExecutionContext
- Method Detail
  - open
```
public void open(ExecutionContext executionContext)
          throws ItemStreamException
```
    Description copied from class: ItemStreamSupport
    No-op.
    Specified by:
    open in interface ItemStream
    Overrides:
    open in class ItemStreamSupport
    Parameters:
    executionContext - current step's ExecutionContext. Will be the executionContext from the last run of the step on a restart.
    Throws:
    ItemStreamException
    See Also:
    ItemStream.open(ExecutionContext)
  - doOpen
```
protected abstract void doOpen(java.io.Serializable checkpoint)
                        throws java.lang.Exception
```
    Used to open a batch artifact with previously saved checkpoint information.
    Parameters:
    checkpoint - previously saved checkpoint object
    Throws:
    java.lang.Exception - thrown by the implementation
  - update
```
public void update(ExecutionContext executionContext)
            throws ItemStreamException
```
    Description copied from class: ItemStreamSupport
    Return empty ExecutionContext.
    Specified by:
    update in interface ItemStream
    Overrides:
    update in class ItemStreamSupport
    Parameters:
    executionContext - to be updated
    Throws:
    ItemStreamException
    See Also:
    ItemStream.update(ExecutionContext)
  - doCheckpoint
```
protected abstract java.io.Serializable doCheckpoint()
                                              throws java.lang.Exception
```
    Used to provide a Serializable representing the current state of the batch artifact.
    Returns:
    the current state of the batch artifact
    Throws:
    java.lang.Exception - thrown by the implementation
  - close
```
public void close()
           throws ItemStreamException
```
    Description copied from class: ItemStreamSupport
    No-op.
    Specified by:
    close in interface ItemStream
    Overrides:
    close in class ItemStreamSupport
    Throws:
    ItemStreamException
    See Also:
    ItemStream.close()
  - doClose
```
protected abstract void doClose()
                         throws java.lang.Exception
```
    Used to close the underlying batch artifact
    Throws:
    java.lang.Exception - thrown by the underlying implementation

Class CheckpointSupport

Constructor Summary

Method Summary

Methods inherited from class org.springframework.batch.item.ItemStreamSupport

Methods inherited from class java.lang.Object

Constructor Detail

CheckpointSupport

Method Detail

open

doOpen

update

doCheckpoint

close

doClose