Top Description Methods
jakarta.batch.api.chunk

public Interface ItemReader

Known Direct Implementers
jakarta.batch.api.chunk.AbstractItemReader
Imports
java.io.Serializable

ItemReader defines the batch artifact that reads items for chunk processing.

Method Summary

Modifier and TypeMethod and Description
public Serializable

Returns:

checkpoint data
checkpointInfo
()

The checkpointInfo method returns the current checkpoint data for this reader.

public void
close()

The close method marks the end of use of the ItemReader.

public void
open(Serializable
specifies the last checkpoint
checkpoint
)

The open method prepares the reader to read items.

public Object

Returns:

next item or null
readItem
()

The readItem method returns the next item for chunk processing.

Method Detail

checkpointInfoback to summary
public Serializable checkpointInfo() throws Exception

The checkpointInfo method returns the current checkpoint data for this reader. It is called before a chunk checkpoint is committed.

Returns:Serializable

checkpoint data

Exceptions
Exception:
is thrown for any errors.
closeback to summary
public void close() throws Exception

The close method marks the end of use of the ItemReader. The reader is free to do any cleanup necessary.

Exceptions
Exception:
is thrown for any errors.
openback to summary
public void open(Serializable checkpoint) throws Exception

The open method prepares the reader to read items. The input parameter represents the last checkpoint for this reader in a given job instance. The checkpoint data is defined by this reader and is provided by the checkpointInfo method. The checkpoint data provides the reader whatever information it needs to resume reading items upon restart. A checkpoint value of null is passed upon initial start.

Parameters
checkpoint:Serializable

specifies the last checkpoint

Exceptions
Exception:
is thrown for any errors.
readItemback to summary
public Object readItem() throws Exception

The readItem method returns the next item for chunk processing. It returns null to indicate no more items, which also means the current chunk will be committed and the step will end.

Returns:Object

next item or null

Exceptions
Exception:
is thrown for any errors.