OSID - osid.transaction.TransactionSession Service Interface Definition

Interface	osid.transaction.TransactionSession
Implements	`osid.OsidSession`
Used By	`osid.transaction.TransactionManager`
Used By	`osid.transaction.TransactionProxyManager`
Description	The transaction session is coordinate transactions. A transaction session allows for `Transactions` to be added to the list of transactions it is managing. Upon a `commit()`, all registered transactions receive a `prepare()` and a `commit()`. Upon an `abort()` all registered transactions receive an `abort()`. A `TransactionSession` itself may implement transactions (as it is an `OsidSession`) as a means of enabling a form of federated transaction management.
Method	add
Description	Adds a Transaction to be managed by this transaction service.
Parameters	`osid.transaction.Transaction`	`transaction`	the transaction to add
Errors	ALREADY_EXISTS		transaction already added
	ILLEGAL_STATE		this transaction has ended
	INVALID_ARGUMENT		the session doesn't support transactions
	NULL_ARGUMENT		a `null` argument provided
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Method	commit
Description	Commits the transaction and makes the state change(s) visible. This transaction is effectively closed and the only valid method that may be invoked is `getState()`.
Errors	ILLEGAL_STATE		this transaction has been committed or aborted
	OPERATION_FAILED		unable to complete request
	PERMISSION_DENIED		authorization failure
Compliance	`mandatory`		This method must be implemented.
Provider Notes	`prepare()` should be invoked on all regstered transactions and iff all are successful should `commit()` be invoked on all registered transactions. In case of error on any `prepare()`, all transactions should be aborted. If an error occurs on a `commit()` after a transaction reported success on a `prepare()` after one or more transactions were already committed, then it is not ACID compliant and success should be assumed by committing the rest of the transactions. If a `commit()` error occurs when no transactions have been committed, then this operation should not proceed.
Method	abort
Description	Cancels this transaction, rolling back the queue of operations since the start of this transaction. This transaction is effectively closed and the only valid method that may be invoked is `getState()`.
Errors	ILLEGAL_STATE		this transaction has been committed or aborted
Compliance	`mandatory`		This method must be implemented.
Provider Notes	Invokes `abort()` on all registered transactions().
Method	getState
Description	Gets the current state of this transaction.
Return	`osid.transaction.TransactionState`		the current state of this transaction
Errors	ILLEGAL_STATE		this transaction has been committed or aborted
Compliance	`mandatory`		This method must be implemented.