org.springframework.batch.item

Interface PeekableItemReader<T>

All Superinterfaces:

ItemReader<T>

All Known Implementing Classes:

SingleItemPeekableItemReader

public interface PeekableItemReader<T>
extends ItemReader<T>

A specialisation of ItemReader that allows the user to look ahead into the stream of items. This is useful, for instance, when reading flat file data that contains record separator lines which are actually part of the next record.

The detailed contract for peek() has to be defined by the implementation because there is no general way to define it in a concurrent environment. The definition of "the next read()" operation is tenuous if multiple clients are reading concurrently, and the ability to peek implies that some state is likely to be stored, so implementations of PeekableItemReader may well be restricted to single threaded use.

Author:

Dave Syer, Mahmoud Ben Hassine

Method Summary

Modifier and Type	Method and Description
T	peek() Get the next item that would be returned by ItemReader.read(), without affecting the result of ItemReader.read().

Methods inherited from interface org.springframework.batch.item.ItemReader

read

Method Detail

peek

@Nullable
T peek()
          throws java.lang.Exception,
                 UnexpectedInputException,
                 ParseException

Get the next item that would be returned by ItemReader.read(), without affecting the result of ItemReader.read().

Returns:

the next item or null if the data source is exhausted

Throws:

java.lang.Exception - if there is a problem

UnexpectedInputException

ParseException