Abstract: 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.

Abstract: 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.

Abstract: Remote method invocation using a generic proxy class. A client machine transmits a call for invocation of a method of a remote object including an identifier for the method object. A server machine receives the identifier and uses generic code to invoke the method object and return an indication of the invoked method along with any relevant parameters.

Abstract: 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.

Abstract: In a distributed computing system, a first process may register interest in an event occurring in another address space or physical machine in such a way as to allow the subsequent notification of the event's occurrence to contain an object that includes methods that are to be run on receipt of the notification. When the notification is received, either by the first process or by some other entity designated by the first process to be the final point of notification, the methods may be executed as specified by the first process.

Abstract: 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.

Abstract: A system consistent with the present invention reduces the number of redundant class descriptors that are sent during remote method calls by using serialization contexts. “Serialization contexts” are dictionary objects that map a class descriptor to a corresponding integer handle. When possible, the integer handle, rather than the full class descriptor, is passed, saving processing time in RMI calls.

Abstract: A homogeneous execution environment operates within a heterogeneous client-server network. A client selects a server and transmits a procedure call with parameters. In response, the system dynamically and securely downloads code to a compute server; invokes a generic compute method; executes the code on the compute server; and returns the results to the calling client method, preserving the result on the compute server if requested. This technique is efficient in that it does not require multiple copies of code to be downloaded or compiled since server byte-codes can be executed on each of the different systems. The code can be compiled once and downloaded as needed to the various servers as byte-codes and then executed.

Abstract: A method and system for leasing storage locations in a distributed processing system is provided. Consistent with this method and system, a client requests access to storage locations for a period of time (lease period) from a server, such as the file system manager. Responsive to this request, the server invokes a lease period algorithm, which considers various factors to determine a lease period during which time the client may access the storage locations. After a lease is granted, the server sends an object to the client that advises the client of the lease period and that provides the client with behavior to modify the lease, like canceling the lease or renewing the lease. The server supports concurrent leases, exact leases, and leases for various types of access. After all leases to a storage location expire, the server reclaims the storage location.

Abstract: 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.

Abstract: Event notification in a distributed system using an object maintained in serialized form, referred to as a marshalled object. For event notification, a machine registers with a device to receive notification of particular events within a network, and a marshalled object is transmitted with a registration request.

Abstract: 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.

Abstract: In a distributed computing system, a first process may register interest in an event occurring in another address space or physical machine in such a way as to allow the subsequent notification of the event's occurrence to contain an object that includes methods that are to be run on receipt of the notification. When the notification is received, either by the first process or by some other entity designated by the first process to be the final point of notification, the methods may be executed as specified by the first process.

Abstract: Methods and systems are provided that facilitate access to a service via a lookup service. A lookup service defines a network's directory of services and stores references to these services. A client desiring use of a service on the network accesses the lookup service, which returns the stub information that facilitates the user's access of the service. The client uses the stub information to access the service.

Abstract: 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.

Abstract: 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 requester 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 requester platform advising of the lease period, and deallocating the system resource when the lease period expires.

Abstract: 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.

Abstract: In a client-server environment it would be desirable to have a number of servers capable of processing a broad range of applications such as compute intensive applications or graphic operations such as rendering. In a heterogeneous client-server environment, conventional systems statically stored executables on a server for later execution. This required extensive storage as well as many programmer hours porting applications to the server machine from client machines which had different object modules. This invention solves these problems by creating a homogeneous execution environment within a heterogenous client-server network. Accordingly, this system dynamically downloads code on a compute server, executes the code on the compute server, and returns the results to the calling client method. This technique does not require multiple copies of code to be downloaded nor compiled since the server code can be executed on all the different systems.

Abstract: 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.

Abstract: 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.