Interface ItemReader

Method Detail

• open

  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 - specifies the last checkpoint

  Throws:

  Exception - is thrown for any errors.

• close

  void close()
      throws Exception

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

  Throws:

  Exception - is thrown for any errors.

• readItem

  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:

  next item or null

  Throws:

  Exception - is thrown for any errors.

• checkpointInfo

  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:

  checkpoint data

  Throws:

  Exception - is thrown for any errors.