TransactionFactory (LinuxForHealth FHIR Server)

java.lang.Object
- org.linuxforhealth.fhir.database.utils.transaction.TransactionFactory

```
public class TransactionFactory
extends java.lang.Object
```
Factory to encapsulate handling of transactions, of which there should be only one active on a thread at a time. This helps to ensure consistent (and correct) commit/rollback handling, which otherwise can get a bit messy.
Usage IConnectionProvider cp = getConnectionProvider(...); try (ITransaction tx = TransactionFactory.open(cp)) { try { doStuff(); } catch (Exception x) { tx.setRollbackOnly(); } } The transaction will commit when AutoCloseable.close() is called, unless setRollbackOnly() was called, in which case a rollback will be performed instead.
To be useable in a JEE context, a light refactor is needed so that an alternative solution can be implemented to use UserTransaction.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`protected static void`	`clearTransaction()`	Remove the transaction from the current thread.
`static TransactionFactory`	`getInstance()`	Singleton instance getter
`static ITransaction`	`getTransaction()`	Get the current transaction.
`static ITransaction`	`openTransaction(IConnectionProvider cp)`	Open a transaction on this thread

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - getInstance
```
public static TransactionFactory getInstance()
```
    Singleton instance getter
    
    Returns:
  - openTransaction
```
public static ITransaction openTransaction(IConnectionProvider cp)
```
    Open a transaction on this thread
    
    Returns:
  - getTransaction
```
public static ITransaction getTransaction()
```
    Get the current transaction.
    
    Returns:
    
    the transaction currently open on this thread
    
    Throws:
    
    java.lang.IllegalStateException - if no transaction is open
  - clearTransaction
```
protected static void clearTransaction()
```
    Remove the transaction from the current thread. Called from SimpleTransaction.close().