nsITransaction

Methods

doTransaction()

Executes the transaction.

undoTransaction()

Restores the state to what it was before the transaction was executed.

redoTransaction()

Executes the transaction again. Can only be called on a transaction that
was previously undone.

In most cases, the redoTransaction() method will actually call the doTransaction() method to execute the transaction again. ### merge(aTransaction) ### Attempts to merge a transaction into "this" transaction. Both transactions must be in their undo state, doTransaction() methods already called. The transaction manager calls this method to coalesce a new transaction with the transaction on the top of the undo stack. This method returns a boolean value that indicates the merge result. A true value indicates that the transactions were merged successfully, a false value if the merge was not possible or failed. If true, the transaction manager will Release() the new transacton instead of pushing it on the undo stack. #### Parameters ####

aTransaction the previously executed transaction to merge.
## Attributes ## ### isTransient ### The transaction's transient state. This attribute is checked by the transaction manager after the transaction's Execute() method is called. If the transient state is false, a reference to the transaction is held by the transaction manager so that the transactions' undoTransaction() and redoTransaction() methods can be called. If the transient state is true, the transaction manager returns immediately after the transaction's doTransaction() method is called, no references to the transaction are maintained. Transient transactions cannot be undone or redone by the transaction manager.