## Appendix A: List of ItemReaders and ItemWriters
### Item Readers
| Item Reader | Description |
|----------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|AbstractItemCountingItemStreamItemReader| Abstract base class that provides basic
restart capabilities by counting the number of items returned from
an `ItemReader`. |
| AggregateItemReader |An `ItemReader` that delivers a list as its
item, storing up objects from the injected `ItemReader` until they
are ready to be packed out as a collection. This class must be used
as a wrapper for a custom `ItemReader` that can identify the record
boundaries. The custom reader should mark the beginning and end of
records by returning an `AggregateItem` which responds `true` to its
query methods `isHeader()` and `isFooter()`. Note that this reader
is not part of the library of readers provided by Spring Batch
but given as a sample in `spring-batch-samples`.|
| AmqpItemReader | Given a Spring `AmqpTemplate`, it provides
synchronous receive methods. The `receiveAndConvert()` method
lets you receive POJO objects. |
| KafkaItemReader | An `ItemReader` that reads messages from an Apache Kafka topic.
It can be configured to read messages from multiple partitions of the same topic.
This reader stores message offsets in the execution context to support restart capabilities. |
| FlatFileItemReader | Reads from a flat file. Includes `ItemStream`and `Skippable` functionality. See [`FlatFileItemReader`](readersAndWriters.html#flatFileItemReader). |
| HibernateCursorItemReader | Reads from a cursor based on an HQL query. See[`Cursor-based ItemReaders`](readersAndWriters.html#cursorBasedItemReaders). |
| HibernatePagingItemReader | Reads from a paginated HQL query |
| ItemReaderAdapter | Adapts any class to the`ItemReader` interface. |
| JdbcCursorItemReader | Reads from a database cursor via JDBC. See[`Cursor-based ItemReaders`](readersAndWriters.html#cursorBasedItemReaders). |
| JdbcPagingItemReader | Given an SQL statement, pages through the rows,
such that large datasets can be read without running out of
memory. |
| JmsItemReader | Given a Spring `JmsOperations` object and a JMS
Destination or destination name to which to send errors, provides items
received through the injected `JmsOperations#receive()`method. |
| JpaPagingItemReader | Given a JPQL statement, pages through the
rows, such that large datasets can be read without running out of
memory. |
| ListItemReader | Provides the items from a list, one at a
time. |
| MongoItemReader | Given a `MongoOperations` object and a JSON-based MongoDB
query, provides items received from the `MongoOperations#find()` method. |
| Neo4jItemReader | Given a `Neo4jOperations` object and the components of a
Cyhper query, items are returned as the result of the Neo4jOperations.query
method. |
| RepositoryItemReader | Given a Spring Data `PagingAndSortingRepository` object,
a `Sort`, and the name of method to execute, returns items provided by the
Spring Data repository implementation. |
| StoredProcedureItemReader | Reads from a database cursor resulting from the
execution of a database stored procedure. See [`StoredProcedureItemReader`](readersAndWriters.html#StoredProcedureItemReader) |
| StaxEventItemReader | Reads via StAX. see [`StaxEventItemReader`](readersAndWriters.html#StaxEventItemReader). |
| JsonItemReader | Reads items from a Json document. see [`JsonItemReader`](readersAndWriters.html#JsonItemReader). |
### Item Writers
| Item Writer | Description |
|--------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| AbstractItemStreamItemWriter | Abstract base class that combines the`ItemStream` and`ItemWriter` interfaces. |
| AmqpItemWriter | Given a Spring `AmqpTemplate`, it provides
for a synchronous `send` method. The `convertAndSend(Object)`method lets you send POJO objects. |
| CompositeItemWriter | Passes an item to the `write` method of each
in an injected `List` of `ItemWriter` objects. |
| FlatFileItemWriter | Writes to a flat file. Includes `ItemStream` and
Skippable functionality. See [`FlatFileItemWriter`](readersAndWriters.html#flatFileItemWriter). |
| GemfireItemWriter | Using a `GemfireOperations` object, items are either written
or removed from the Gemfire instance based on the configuration of the delete
flag. |
| HibernateItemWriter | This item writer is Hibernate-session aware
and handles some transaction-related work that a non-"hibernate-aware"
item writer would not need to know about and then delegates
to another item writer to do the actual writing. |
| ItemWriterAdapter | Adapts any class to the`ItemWriter` interface. |
| JdbcBatchItemWriter | Uses batching features from a`PreparedStatement`, if available, and can
take rudimentary steps to locate a failure during a`flush`. |
| JmsItemWriter | Using a `JmsOperations` object, items are written
to the default queue through the `JmsOperations#convertAndSend()` method. |
| JpaItemWriter | This item writer is JPA EntityManager-aware
and handles some transaction-related work that a non-"JPA-aware"`ItemWriter` would not need to know about and
then delegates to another writer to do the actual writing. |
| KafkaItemWriter |Using a `KafkaTemplate` object, items are written to the default topic through the`KafkaTemplate#sendDefault(Object, Object)` method using a `Converter` to map the key from the item.
A delete flag can also be configured to send delete events to the topic.|
| MimeMessageItemWriter | Using Spring’s `JavaMailSender`, items of type `MimeMessage`are sent as mail messages. |
| MongoItemWriter | Given a `MongoOperations` object, items are written
through the `MongoOperations.save(Object)` method. The actual write is delayed
until the last possible moment before the transaction commits. |
| Neo4jItemWriter | Given a `Neo4jOperations` object, items are persisted through the`save(Object)` method or deleted through the `delete(Object)` per the`ItemWriter’s` configuration |
|PropertyExtractingDelegatingItemWriter| Extends `AbstractMethodInvokingDelegator`creating arguments on the fly. Arguments are created by retrieving
the values from the fields in the item to be processed (through a`SpringBeanWrapper`), based on an injected array of field
names. |
| RepositoryItemWriter | Given a Spring Data `CrudRepository` implementation,
items are saved through the method specified in the configuration. |
| StaxEventItemWriter | Uses a `Marshaller` implementation to
convert each item to XML and then writes it to an XML file using
StAX. |
| JsonFileItemWriter | Uses a `JsonObjectMarshaller` implementation to
convert each item to Json and then writes it to an Json file.