Sharing objects in runtime systems

• US 20050262512A1
• Filed: 05/20/2004
• Published: 11/24/2005
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: SAP SE
• Original Assignee: SAP AG (SAP SE)
• Inventors: Dosert, Jan, Schmelter, Ralf, Schmidt, Oliver, Hilgenberg, Arno, Kuck, Norbert, Lott, Edgar, Strassburger, Martin
• Granted Patent: US 7,587,721 B2
• Time in Patent Office: Days
• US Class Current: 719/310
• CPC Class Codes: G06F 2209/5016 Session
• CPC Class Codes: G06F 2209/5018 Thread allocation
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: G06F 9/5027 the resource being a machine, e.g. CPUs, Servers, Terminals

Abstract

Methods and apparatus, including computer systems and program products, for sharing objects in runtime systems. A set of objects is identified, each object having a reference to runtime metadata about the object in a first runtime system. The reference to the runtime metadata in each object is replaced with a proxy, and the set of objects is transmitted to a second runtime system, where the proxy in each object is replaced with a reference to runtime metadata about the object in the second runtime system. In some implementations, the runtime metadata can be installed in the second runtime system if it is not already available. The set of objects can include a shared closure of objects, which can be shared between runtime systems (including virtual machines) located on distinct physical machines. Sharing objects between runtime systems on multiple machines can provide isolation between user sessions in a scalable manner.

Claims

1. A computer program product, stored on a machine-readable medium, the computer program product being operable to cause data processing apparatus to:

identify a set of data objects, each data object in the set of data objects comprising a reference to runtime metadata about the data object in a first runtime system;

for each data object in the set of data objects, replace the reference to the runtime metadata in the data object with a proxy; and

transmit the set of data objects to a second runtime system.

2. The computer program product of claim 1, wherein for each data object in the set of data objects, the reference to the runtime metadata about the data object comprises a reference to a runtime representation of a class of which the data object is an instance.

3. The computer program product of claim 2, wherein the first runtime system comprises a first virtual machine and the second runtime system comprises a second virtual machine.

4. The computer program product of claim 3, wherein the first virtual machine and the second virtual machine are Java virtual machines or Common Language Runtime virtual machines.

5. The computer program product of claim 1, wherein the first runtime system is located on a first physical machine and the second runtime system is located on a second, distinct physical machine.

6. The computer program product of claim 1, wherein identifying the set of data objects comprises identifying a transitive closure of one or more referenced data objects, each of the referenced data objects being referenced by a first data object.

7. A computer program product, stored on a machine-readable medium, the computer program product being operable to cause data processing apparatus to:

receive a set of data objects from a first runtime system, each data object in the set of data objects comprising a proxy;

copy the set of data objects into a second runtime system; and

for each data object in the set of data objects;

identify runtime metadata about the data object; and

replace the proxy in the data object with a reference to the runtime metadata about the data object.

8. The computer program product of claim 7, wherein the computer program product is further operable to:

for each data object in the set of data objects;

determine if the runtime metadata about the data object is available in the second runtime system; and

if the runtime metadata about the data object is not available in the second runtime system, install the runtime metadata about the data object in the second runtime system.

9. The computer program product of claim 7, wherein for each data object in the set of data objects, the reference to the runtime metadata about the data object comprises a reference to a runtime representation of a class of which the data object is an instance.

10. The computer program product of claim 9, wherein the instructions are further operable to cause the data processing apparatus to:

for each data object in the set of data objects;

determine whether the runtime representation of the class of which the data object is an instance is available in the second runtime system; and

if the runtime representation of the class of which the data object is an instance is not available in the second runtime system, install the runtime representation of the class of which the data object is an instance in the second runtime system.

11. The computer program product of claim 9, wherein the first runtime system comprises a first virtual machine and the second runtime system comprises a second virtual machine.

12. The computer program product of claim 11, wherein the first virtual machine and the second virtual machine are Java virtual machines or Common Language Runtime virtual machines.

13. The computer program product of claim 7, wherein the first runtime system is located on a first physical machine and the second runtime system is located on a second, distinct physical machine.

14. The computer program product of claim 7, wherein the set of data objects consists of a first data object and a transitive closure of one or more referenced data objects, each of the referenced data objects being referenced by the first data object.

15. The computer program product of claim 7, wherein the operations to identify the runtime metadata and replace the proxy in each data object in the set of data objects occur substantially immediately after the set of data objects is received.

16. The computer program product of claim 7, wherein for each data object in the set of data objects, the operations to identify the runtime metadata and replace the proxy in the data object occur when the data object is first accessed in the second runtime system.

17. A computer-implemented method comprising:

identifying a set of data objects, each data object in the set of data objects comprising a reference to runtime metadata about the data object in a first runtime system;

for each data object in the set of data objects, replacing the reference to the runtime metadata in the data object with a proxy; and

transmitting the set of data objects to a second runtime system.

18. An apparatus comprising:

means for identifying a set of data objects, each data object in the set of data objects comprising a reference to runtime metadata about the data object in a first runtime system;

means for replacing the reference to the runtime metadata in each data object in the set of data objects with a proxy; and

means for transmitting the set of data objects to a second runtime system.

19. A computer-implemented method comprising:

receiving a set of data objects from a first runtime system, each data object in the set of data objects comprising a proxy;

copying the set of data objects into a second runtime system; and

for each data object in the set of data objects;

identifying runtime metadata about the data object; and

replacing the proxy in the data object with a reference to the runtime metadata about the data object.

20. An apparatus comprising:

means for receiving a set of data objects from a first runtime system, each data object in the set of data objects comprising a proxy;

means for copying the set of data objects into a second runtime system; and

means for identifying runtime metadata about each data object in the set of data objects and for replacing the proxy in each data object with a reference to the runtime metadata about the data object.