org.apache.chemistry.opencmis.commons.spi.Holder<T>

org.alfresco.opencmis.TransactionAwareHolder<T>

public class TransactionAwareHolder<T> extends org.apache.chemistry.opencmis.commons.spi.Holder<T>

A Tx aware wrapper around Holder.

This wrapper is created in CMISTransactionAwareHolderInterceptor. It is designed to handle the state of the Holder in case of tx retries which are handled by RetryingTransactionInterceptor.

There are a few things that influenced the implementation of this wrapper and need to be taken into account:

The wrapper is created in CMISTransactionAwareHolderInterceptor and is replacing the incoming parameter (Holder) in the call to AlfrescoCmisServiceImpl.
The calls to AlfrescoCmisServiceImpl generally return nothing, therefore the state of Holder or it's wrapper (TransactionAwareHolder) is modified inside the AlfrescoCmisServiceImpl and then read in CMIS layer.
The CMISTransactionAwareHolderInterceptor is called after RetryingTransactionInterceptor but due to internal counter in Spring AOP it is not called again if the tx is retried. The proxied service (AlfrescoCmisServiceImpl) is called straight away. Fortunately the parameter replacing is not required for the second time. The wrapper (TransactionAwareHolder) will still be used.
The TransactionAwareHolder<T>.org.alfresco.opencmis.TransactionAwareHolder.TxAwareHolderListener is bound to the tx when the internal value is read. This is done this way because once the tx is rolled backed the listener list is cleared. The TransactionAwareHolder<T>.org.alfresco.opencmis.TransactionAwareHolder.TxAwareHolderListener is still required to be called once the retry succeeds with a commit. The CMISTransactionAwareHolderInterceptor cannot recreate the TransactionAwareHolder as the interceptor is called only once. It is safe to bind the same listener many times as it is always the same object.

Class TransactionAwareHolder<T>

Method Summary