摘要:
A database system wherein one or more entry databases store a plurality of entries. Each entry is of a given type that defines the fields of the entry. Each field contains or identifies an object with associated attributes or data. The type of each entry may further define behavior in the form of methods the entry can implement. An entry type which is a subtype of another inherits all fields and behavior of its super-type, and contains additional fields and/or defines new/modified behavior. Entries may be expressed in a Java™ programming language. The database system may further employ a search engine which allows queries to be made upon entries in the database. In one implementation, the queries include a read operation, a take operation, and a notify operation. Each query request includes a command indicating the type of operation, and a template which is an entry object having some or all of its fields set to specific values that must be matched exactly. Other fields of the template entry may be specified as wildcards, whose values do not matter. The search engine may further be configured to create an index for caching entries having characteristics which are commonly specified by queries. In one implementation, the databases may also store sets of entries which are matched using sets of templates.
摘要:
The method and apparatus for generating and employing a run-time generated stub to reference an object in an object oriented system. This method and apparatus represents in a first virtual machine a remote object implemented in a second virtual machine by employing a stub class. An object reference is sent by the second virtual machine and received by the first virtual machine. The object reference includes an interface descriptor that identifies the interface(s) of the remote object and an object handle that identifies the remote object. At run-time, the information associated with the remote object is transformed into a stub class that represents the remote object and implements only those interfaces identified by the interface descriptor and also defined by the first virtual machine. After the stub class is created, an instance of that stub class is generated and provided to the first virtual machine. In an alternative embodiment, an interface specific stub is created for each interface that is identified by the interface descriptor and defined by the first virtual machine. The interface specific stub is created at compile time. A delegator stub class is created at run-time that delegates to the interface specific stub(s).
摘要:
An object oriented distributed computing system is provided. Processing means call a location service within automatically generated stubs in response to a request for a service provided by a particular object. The location service is automatically called on behalf of the requester to locate the target object when the request is issued. Multiple Object Managers reflecting multiple Object Models are permitted in the system. Programmers and users do not need to know the Object Model adhered to by an Object Manager. A request to any object in the system is independent of the Object Model of the sought object's Object Manager. A generic interface enables new Object Managers reflecting new Object Models to be easily added to the system. Availability of the target object is independent of association of the target object with a process at the time the request was issued. Deactivation of processes is automatically accomplished in response to the system needing resources.
摘要:
Use of a smart proxy as a wrapper around a stub in a distributed system. Instead of receiving a stub as a result of a remote procedure call, a caller receives a smart proxy including the stub as an embedded object. The smart proxy performs predefined processing associated with a remote procedure call, the processing possibly occurring before, during, or after a response to the call.
摘要:
An improved lookup service is provided that allows for the dynamic addition and deletion of services. This lookup service allows for the addition and deletion of services automatically, without user intervention. As a result, clients of the lookup service may continue using the lookup service and its associated services while the updates occur. Additionally, the lookup service provides a notification mechanism that can be used by clients to receive a notification when the lookup service is updated. By receiving such a notification, clients can avoid attempting to access a service that is no longer available and can make use of new services as soon as they are added to the lookup service.
摘要:
In accordance with the present invention a process is provided for allocating and deallocating resources in a distributed processing system having a requester platform and a server platform. The process involves receiving a request from the requestor platform referring to a system resource and specifying a requested lease period, permitting shared access to the system resource for a lease period, sending a return call to the requestor platform advising of the lease period, and deallocating the system resource when the lease period expires.
摘要:
Use of a policy object for verification in a distributed system. A machine downloads a policy object containing a reference to code governing verification of data. The machine uses the reference to obtain the code and locally verify data or other information. As particular rules for the data change, the policy object may be updated to provide a reference to the code for the new rules when it is downloaded.
摘要:
A distributed computer system uses a single interface at the client site to handle calls to call both active and passive remote objects. Accordingly, the calling process does not need to be aware of distinctions between active and passive objects. Further, remote objects are aggregated into common groups of objects, thereby providing greater security between objects of disparate groups and efficiency between related objects of the same group. Preferably, different groups are run on different Java virtual machines.
摘要:
A system for leasing a group membership in a distributed processing system is provided. In accordance with this system, a remote object requests from an activation group a membership in the activation group for a period of time. Responsive to this request, the activation group determines an appropriate lease period during which time the remote object becomes a member of the activation group and runs in the same address space as other objects of the activation group.
摘要:
In accordance with the present invention a process is provided for allocating and deallocating resources in a distributed processing system having a requester platform and a server platform. The process involves receiving a request from the requestor platform referring to a system resource and specifying a requested lease period, permitting shared access to the system resource for a lease period, sending a return call to the requestor platform advising of the lease period, and deallocating the system resource when the lease period expires.