org.springframework.batch.item.database

## Class JpaItemWriter<T>

- java.lang.Object
- - org.springframework.batch.item.database.JpaItemWriter<T>

- All Implemented Interfaces:
    ItemWriter<T>, org.springframework.beans.factory.InitializingBean

      public class JpaItemWriter<T>
      extends java.lang.Object
      implements ItemWriter<T>, org.springframework.beans.factory.InitializingBean

  `ItemWriter` that is using a JPA EntityManagerFactory to merge any Entities that aren't part of the persistence context. It is required that `write(List)` is called inside a transaction.
  The reader must be configured with an `EntityManagerFactory` that is capable of participating in Spring managed transactions. The writer is thread-safe after its properties are set (normal singleton behaviour), so it can be used to write in multiple concurrent transactions.
  Author:
    Thomas Risberg

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected static org.apache.commons.logging.Log` | `logger`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `JpaItemWriter()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `afterPropertiesSet()` Check mandatory properties - there must be an entityManagerFactory.
    `protected void` | `doWrite(javax.persistence.EntityManager entityManager, java.util.List<? extends T> items)` Do perform the actual write operation.
    `void` | `setEntityManagerFactory(javax.persistence.EntityManagerFactory entityManagerFactory)` Set the EntityManager to be used internally.
    `void` | `write(java.util.List<? extends T> items)` Merge all provided items that aren't already in the persistence context and then flush the entity manager.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### logger

          protected static final org.apache.commons.logging.Log logger

  - ### Constructor Detail

    - #### JpaItemWriter

          public JpaItemWriter()

  - ### Method Detail

    - #### setEntityManagerFactory

          public void setEntityManagerFactory(javax.persistence.EntityManagerFactory entityManagerFactory)

      Set the EntityManager to be used internally.
      Parameters:
        `entityManagerFactory` - the entityManagerFactory to set

    - #### afterPropertiesSet

          public void afterPropertiesSet()
                                  throws java.lang.Exception

      Check mandatory properties - there must be an entityManagerFactory.
      Specified by:
        `afterPropertiesSet` in interface `org.springframework.beans.factory.InitializingBean`
      Throws:
        `java.lang.Exception`

    - #### write

          public void write(java.util.List<? extends T> items)

      Merge all provided items that aren't already in the persistence context and then flush the entity manager.
      Specified by:
        `write` in interface `ItemWriter<T>`
      Parameters:
        `items` - items to be written
      See Also:
        `ItemWriter.write(java.util.List)`

    - #### doWrite

          protected void doWrite(javax.persistence.EntityManager entityManager,
                                 java.util.List<? extends T> items)

      Do perform the actual write operation. This can be overridden in a subclass if necessary.
      Parameters:
        `entityManager` - the EntityManager to use for the operation
        `items` - the list of items to use for the write