read
@Nullable
public T read()
throws java.lang.Exception
Reads a piece of input data and advance to the next one. Implementations
must return null
at the end of the input
data set. In a transactional setting, caller might get the same item
twice from successive calls (or otherwise), if the first call was in a
transaction that rolled back.
- Specified by:
read
in interface ItemReader<T>
- Returns:
- return value of the target method.
- Throws:
ParseException
- if there is a problem parsing the current record
(but the next one may still be valid)
NonTransientResourceException
- if there is a fatal exception in
the underlying resource. After throwing this exception implementations
should endeavour to return null from subsequent calls to read.
UnexpectedInputException
- if there is an uncategorised problem
with the input data. Assume potentially transient, so subsequent calls to
read might succeed.
java.lang.Exception
- if an there is a non-specific error.