Abstract: One aspect of the invention is a distributed object system comprising a plurality of resources and a plurality of transactions where at least some of the plurality of transactions make use of at least one of the plurality of resources. A transaction service runs on at least one computer and is operable to interact with the resources and transactions. The transaction service comprises a deadlock detector operable to determine whether deadlock will occur if one of the plurality of transactions waits to use a resource currently being used by another of the plurality of transactions. A roll back method is operable to roll back a particular transaction if the deadlock detector determines that deadlock will occur if that particular transaction waits to use a resource currently being used by another of the plurality of transactions.

Abstract: One aspect of the invention is a method for processing a query. The method comprises receiving a query requesting at least one specific attribute of selected ones of a plurality of objects satisfying a query criteria. The query is directed to a database containing state data for the plurality of objects. A data structure is generated in response to the query, the data structure comprising, for each object satisfying the query criteria, each specific attribute requested by the query and the identifier of the object, even if the identifier of the object was not requested as a specific attribute in the query.

Abstract: One aspect of the invention is a method for maintaining persistence in a shared object system. A request is received to update a persistent record of a shared object's state wherein the persistent record of the shared object's state is contained in a database. At least one SQL statement is dynamically generated in response to the request. That statement is generated using a data structure comprising data reflecting at least a portion of the state of the shared object and a map associating attributes to the shared object with the location of those attributes in the database. An SQL statement is then sent to the database.

Abstract: One aspect of the invention is a method for updating a database providing persistent storage for a plurality of objects each comprising methods and instance variables, wherein a persistent record of each of the plurality of objects will experience a change in the context of a transaction if the transaction is allowed to commit. The method comprises sending a first prepare message to each of the plurality of objects, the plurality of objects sending their state to the database in response to the first prepare messages. A second prepare message is sent to the database if a prepared indicator was received in response to each of the first prepare messages. A commit message is sent to each of the plurality of objects and to the database if a prepared indicator was received in response to each of the first prepare messages and if a prepared indicator was received in response to the second prepare message.

Abstract: One aspect of the invention is a method for managing redundant objects in a distributed object system. A transaction service runs on a computer. At least two copies of the instance variables of a distributed object are maintained in a separate database. The distributed object (46) has a polymorphism of an interface object instantiation method. At least two copies of an interface object (48) are instantiated wherein each interface object (48) is associated with one of the copies of the instance variables of the distributed object (46). The interface objects (48) are instantiated using the polymorphism. A list of interface objects (48) is maintained with the distributed object (46). Each copy of the instance variables of the distributed object (46) are modified by traversing the list of interface objects (48) and sending a message with modification parameters to each interface object (48) on the list.

Abstract: One aspect of the invention is a method of generating object-oriented code. An object model is captured for at least one object using a computer. Code interpretable by a compiler is then generated based upon the object model. The code comprises a base object class (46) and a custom object class (50) where the base object class (46) comprises a base object header file and base object implementation file while the custom object class (50) comprises a custom object header file and custom object implementation file. The base object class (46) inherits from a framework object class (44) while the custom object class (50) inherits from the base object class (46). In response to a change in the object model, a new base object header file, base object implementation file, and custom object header file are generated while preserving at least some code in the base object implementation file.

Abstract: The invention comprises a system and method for maintaining the integrity of a plurality of objects each comprising methods and instance variables. The method is used to maintain the integrity of a plurality of objects wherein each of the plurality of objects will experience a change in at least one of its instance variables in response to a transaction if the transaction is allowed to commit. The method comprises sending a validate message to ones of the plurality of objects using a transaction service running on a computer. A prepare message is sent to each of the plurality of objects if a valid indicator was received in response to each validate message. A commit message is sent to each of the plurality of objects if a valid indicator was received in response to each of the validate messages and a prepared indicator was received in response to each of the prepare messages.