Appendix A: List of ItemReaders and ItemWriters

Item Readers

Table 1. Available 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”.

HibernateCursorItemReader

Reads from a cursor based on an HQL query. See Cursor-based ItemReaders.

HibernatePagingItemReader

Reads from a paginated HQL query.

ItemReaderAdapter

Adapts any class to the ItemReader interface.

JdbcCursorItemReader

Reads from a database cursor over JDBC. See “Cursor-based ItemReaders”.

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

StaxEventItemReader

Reads over StAX. see StaxEventItemReader.

JsonItemReader

Reads items from a Json document. see JsonItemReader.

Item Writers

Table 2. Available Item Writers
Item Writer Description

AbstractItemStreamItemWriter

Abstract base class that combines the ItemStream and ItemWriter interfaces.

AmqpItemWriter

Given a Spring AmqpTemplate, 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 item in an injected List of ItemWriter objects.

FlatFileItemWriter

Writes to a flat file. Includes ItemStream and Skippable functionality. See “FlatFileItemWriter”.

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 by 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), as dictated by 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 by using StAX.

JsonFileItemWriter

Uses a JsonObjectMarshaller implementation to convert each item to Json and then writes it to a Json file.