# Package org.springframework.batch.item

Infrastructure interfaces and primary dependencies for item concerns.

See: Description

- Interface Summary
  Interface | Description
  --- | ---
  ItemCountAware | Marker interface indicating that an item should have the item count set on it.
  ItemProcessor<I,O> | Interface for item transformation.
  ItemReader<T> | Strategy interface for providing the data.
  ItemStream | Marker interface defining a contract for periodically storing state and restoring from that state should an error occur.
  ItemStreamReader<T> | Convenience interface that combines `ItemStream` and `ItemReader` .
  ItemStreamWriter<T> | Convenience interface that combines `ItemStream` and `ItemWriter` .
  ItemWriter<T> | Basic interface for generic output operations.
  PeekableItemReader<T> | A specialisation of `ItemReader` that allows the user to look ahead into the stream of items.
  ResourceAware | Marker interface indicating that an item should have the Spring `Resource` in which it was read from, set on it.

- Class Summary
  Class | Description
  --- | ---
  ExecutionContext | Object representing a context for an `ItemStream`.
  ItemStreamSupport | Empty method implementation of `ItemStream`.
  KeyValueItemWriter<K,V> | A base class to implement any `ItemWriter` that writes to a key value store using a `Converter` to derive a key from an item
  SpELItemKeyMapper<K,V> | An implementation of `Converter` that uses SpEL to map a Value to a key

- Exception Summary
  Exception | Description
  --- | ---
  ItemReaderException | A base exception class that all exceptions thrown from an `ItemReader` extend.
  ItemStreamException | Exception representing any errors encountered while processing a stream.
  ItemWriterException | A base exception class that all exceptions thrown from an `ItemWriter` extend.
  NonTransientResourceException | Exception indicating that an error has been encountered doing I/O from a reader, and the exception should be considered fatal.
  ParseException | Exception indicating that an error has been encountered parsing IO, typically from a file.
  ReaderNotOpenException | Exception indicating that an `ItemReader` needed to be opened before read.
  UnexpectedInputException | Used to signal an unexpected end of an input or message stream.
  WriteFailedException | Unchecked exception indicating that an error has occurred while trying to clear a buffer on a rollback.
  WriterNotOpenException | Exception indicating that an `ItemWriter` needed to be opened before being written to.

## Package org.springframework.batch.item Description

Infrastructure interfaces and primary dependencies for item concerns.