Abstract: A dependency checking apparatus and method allows checking the version of classes in an object-oriented program to assure the proper version is being used for each release of the software. According to a first preferred embodiment, classes themselves include static code that checks dependencies when the class is loaded. The first embodiment is simple to implement for classes. According to a second preferred embodiment, information relating to version checking is stored separate from the classes and is used to check dependencies. This second embodiment is more flexible, allowing the checking of interfaces as well as classes, and allows the dependency information to be altered without recompiling the classes being checked.

Abstract: A method and apparatus for providing persistence in a Java environment is provided. The method and apparatus provide object persistence in way that can be adapted for use in a wide variety of situations. In accordance with the preferred embodiment a StoragePlugin class is defined which includes the methods needed to provide orthogonal persistence in the Java environment. StoragePlugin objects are then instantiated as needed from the StoragePlugin class. Each StoragePlugin object implements the defined methods in a way that is compatible with a particular persistent storage system that is to be used (i.e., a particular hardware and database system).

Abstract: The present invention provides an object-oriented disabling mechanism which selectively disables object methods. The object-oriented disabling mechanism prevents the selected methods from being called on an object by other programs or processes via various alternative embodiments. A first preferred embodiment of the object-oriented disabling mechanism works in conjunction with a plurality of method tables to restrict method calls on an object. An alternative preferred embodiment of the object oriented disabling mechanism works in conjunction with a read flag and a write flag to define which methods can be called on an object. Another alternative preferred embodiment of the object oriented disabling mechanism uses software “locks” and a lock conflict matrix associated with the object to determine which methods can be called on an object.

Abstract: The present invention provides a method and apparatus for versioning persistent objects which updates the version of a persistent object by splitting the persistent object up into two sections, a header section and a data section. The header section has a data pointer to the data section. The header section determines the object identity of the persistent object and always remains in place. Since the header section of the object always remains intact, the object identity of the persistent object never changes. When updating the version of the persistent object, the persistent object versioning mechanism simply updates the pointer in the header section of the object to reference a newly created data section. Once the persistent object versioning mechanism updates the data pointer to reference the new data section, existing objects can reference the new version of the persistent object using the original object identity of the persistent object.

Abstract: According to the present invention, an apparatus and method for providing access to multiple object versions allows the system administrators to control which version of a given object is referenced by existing related objects. By providing an option for the system user to select and access different object versions, object upgrade policies can be flexible and accommodate the various needs of different object-oriented systems. The object versioning mechanism of the present invention provides several different options when modifying an existing object to create a new version. The various embodiments of the present invention provide a versioning mechanism to manage version updates for objects in an object-oriented system. The versioning mechanism disclosed herein implements the methods of the present invention by making a copy of an existing object whenever a new version of the existing object is to be introduced into an object-oriented system.

Abstract: According to the present invention, an object change manager includes methods afterCreation( ), beforeDeletion( ), beforeChange( ) and afterChange( ) that may be invoked when an object is changed. The object change manager automatically updates all data structures, such as indexes and has tables, that correspond to the object being changed when one of these methods is called. The object change manager is an extensible framework that allows a programmer to define custom change management environments. The object change manager of the preferred embodiments is a portion of code that automatically propagates changes to objects to their corresponding data structures in a way that is transparent to the programmer, without requiring excessive overhead in the object infrastructure code.

Abstract: According to the preferred embodiment of the present invention, a method and apparatus for facilitating communications between client objects and server objects in a distributed object system is provided. The method and apparatus provide a distributed thread that associates dedicated service threads with a distributed thread identification for each transaction. By associating a dedicated service thread with a distributed thread identification it can be assured that all portions of a transaction are performed by the same thread. Thus, the present invention assures consistent thread allocation in a distributed system.

Abstract: The method maintenance mechanism of the present invention is comprised of two submechanisms, a method update mechanism and a method call manager. The method update mechanism is used to make changes to existing methods. The method call manger manages calls to methods in a way that allows active programs to continue to use old versions of methods while at the same time providing access to new method versions when programs are reactivated or activated for the first time.

Abstract: A second object is created which is an instance of a first class. The data from the first object is copied into the second object. The method table pointer of the first object is then changed to the method table of the second class. The data section of the first object is then reallocated according to the data requirements of the second class. The data in the second object is then converted to data in the first object. The resultant first object has both methods and data updated to the second class without passivating the object.

Abstract: An apparatus and method for updating objects sets up morphing on affected classes, and the actual morph of each object is performed the first time the object is touched, i.e., the first time a method on the object is invoked after the morph is set up. Morphing objects on first touch allows an application that requires a new object configuration to be loaded and executed immediately, because new methods and/or data will become available when an instance is first touched. The apparatus and method of the invention set up morphing on first touch by overriding methods on the old class with morph and retry methods that first perform the morph of the object, then route the method call to the newly morphed object. The first touch of an object to be updated thus updates (or morphs) the object, and each subsequent access will be to the updated object.

Abstract: An object identity swapper dynamically updates the configuration of an object by taking a first object, instantiating a new second object, swapping the identities of the first and second objects, and reading and converting the state data of the old object (now the second object) into the new object (now the first object). The result is that the first object identity doesn't change, but its configuration is updated without passivating the object.