Package org.springframework.batch.support.transaction

Class TransactionAwareProxyFactory<T>

java.lang.Object
org.springframework.batch.support.transaction.TransactionAwareProxyFactory<T>
public class TransactionAwareProxyFactory<T> extends Object

Factory for transaction aware objects (like lists, sets, maps). If a transaction is active when a method is called on an instance created by the factory, it makes a copy of the target object and carries out all operations on the copy. Only when the transaction commits is the target re-initialised with the copy.

Works well with collections and maps for testing transactional behaviour without needing a database. The base implementation handles lists, sets and maps. Subclasses can implement begin(Object) and commit(Object, Object) to provide support for other resources.

Generally not intended for multi-threaded use, but the append only version of collections gives isolation between threads operating on different keys in a map, provided they only append to the map. (Threads are limited to removing entries that were created in the same transaction.)

Author:
Dave Syer

  • Method Details

    • begin

      protected final T begin(T target)
      Make a copy of the target that can be used inside a transaction to isolate changes from the original. Also called from the factory constructor to isolate the target from the original value passed in.
      Parameters:
      target - the target object (List, Set or Map)
      Returns:
      an independent copy

    • commit

      protected void commit(T copy, T target)
      Take the working copy state and commit it back to the original target. The target then reflects all the changes applied to the copy during a transaction.
      Parameters:
      copy - the working copy.
      target - the original target of the factory.

    • createTransactionalMap

      public static <K, V> Map<K,V> createTransactionalMap()

    • createTransactionalMap

      public static <K, V> Map<K,V> createTransactionalMap(Map<K,V> map)

    • createAppendOnlyTransactionalMap

      public static <K, V> ConcurrentMap<K,V> createAppendOnlyTransactionalMap()

    • createAppendOnlyTransactionalSet

      public static <T> Set<T> createAppendOnlyTransactionalSet()

    • createTransactionalSet

      public static <T> Set<T> createTransactionalSet()

    • createTransactionalSet

      public static <T> Set<T> createTransactionalSet(Set<T> set)

    • createAppendOnlyTransactionalList

      public static <T> List<T> createAppendOnlyTransactionalList()

    • createTransactionalList

      public static <T> List<T> createTransactionalList()

    • createTransactionalList

      public static <T> List<T> createTransactionalList(List<T> list)