Abstract: A transaction system implemented on a server machine for maintaining consistency in an information system supporting asynchronous transactions. The information system includes a database shared among a plurality of users and implemented on a client machine. The transaction system is invoked at run-time for a transaction where the transaction includes one or more subtransaction steps. The transaction system includes a graphical user interface for receiving a user defined isolation level selection for executing a transaction between the server machine and the database or application, a persistent service for storing object state information for each object affected in the execution of each subtransaction step and a state verification service for verifying the state of each object affected by a subtransaction step to verify the state of the object is the same as a last time the object was seen in the transaction.

Abstract: In general, in one aspect, the invention provides a modular application collaborator for providing inter-operability between applications including a plurality of connectors for communicating with a like plurality of applications and an interchange server. The interchange server includes an application collaboration module and service module. The service module transfers messages between connectors and the application collaboration module. The application collaboration defines the inter-operability between two or more applications. The interchange server service module includes a transaction service and an error service. Transactions are executed in the application collaboration module and the transaction service records each action and a compensating action for undoing an associated action.