Method and apparatus for generating and using location-independent distributed object references

• US 9,146,789 B2
• Filed: 03/21/2006
• Issued: 09/29/2015
• Est. Priority Date: 03/21/2006
• Status: Active Grant

• Current Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Original Assignee: Oracle America, Inc. (Oracle Corporation)
• Inventors: Waldo, James H., Blackman, Timothy J., Ellard, Daniel J., Warres, Michael P., Sproull, Robert F., Loizeaux, Jane A.
• Primary Examiner(s): Kraft, Shih-Wei
• Application Number:
  US11/385,164
• Publication Number:
  US 20070226758A1
• Time in Patent Office: 3,479 Days
• Field of Search: 709203-205, 709242-245, 713/167, 707103 R-103 Z, 719/310, 719/316, 719/330
• US Class Current: 1/1
• CPC Class Codes: G06F 2209/463 Naming
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: G06F 9/548 Object oriented; Remote method invocation [RMI] non-remote method invocation G06F9/449

Abstract

Location-independent references include a live reference containing a location of a remote object and a universally unique identifier (UUID) which provides a unique global reference to that remote object. If a method call to the remote object using the live reference fails, the UUID is used to obtain a new reference to the remote object and the new reference is then used to make another method call. A new reference can be obtained from an identifier directory that contains a mapping between UUIDs and location-independent references. When a remote object is first created, or when a remote object is moved from one location to another, the remote object registers with any and all such directories that it can find in its environment. These registrations are leased; that is, if they are not occasionally refreshed by the remote object which registered them, they are dropped from the directory.

Claims

1. A tangible non-transitory computer-readable storage medium having a series of computer instructions fixed thereon, and executable by a computer to cause the computer to perform a method for making a method call on a remote object, comprising:

(a) constructing a location-independent proxy object that includes (1) a live reference containing a location of the remote object, (2) a universally unique identifier (UUID) which provides a unique global reference to that remote object, and (3) a refresh proxy method;

(b) making a method call on the remote object using the live reference;

(c) when the method call made in step (b) fails, using the UUID that is included in the location-independent proxy object to obtain a new reference to the remote object by using the refresh proxy method; and

(d) using the new reference to make another method call on the remote object.

2. The storage medium of claim 1 wherein step (c) comprises:

(c1) using at least one identifier directory that contains a mapping between UUIDs and location-independent proxy objects to obtain the new reference.

3. The storage medium of claim 2 wherein step (c1) comprises using the remote object to perform a registration with at least one identifier directory when the remote object is first created and when a remote object is moved from one location to another.

4. The storage medium of claim 3 wherein the remote object periodically refreshes the registration.

5. The storage medium of claim 1 wherein the location-independent proxy object contains hints to facilitate the location of identifier directories.

6. The storage medium of claim 1 wherein step (c) comprises using the location-independent proxy object to inform a client that the remote object has been moved whereupon the client uses the UUID to obtain a new reference to the remote object.

7. The storage medium of claim 6 wherein the location-independent proxy object informs the client that the remote object has been moved by generating a special exception.

8. Apparatus including a programmed computer, the computer including a tangible non-transitory computer-readable storage medium having instructions stored thereon that are executable by the computer for making a method call on a remote object, the instructions implementing:

a reference generator that constructs a location-independent proxy object including (1) a live reference containing a location of the remote object, (2) a universally unique identifier (UUID) which provides a unique global reference to that remote object, and (3) a refresh proxy method;

a call mechanism that makes a method call on the remote object using the live reference;

a lookup mechanism operable when the method call made by the call mechanism fails, that uses the UUID that is included in the location-independent proxy object to obtain a new reference to the remote object by using the refresh proxy method; and

a mechanism that uses the new reference to make another method call on the remote object.

9. The apparatus of claim 8 wherein the lookup mechanism comprises a directory mechanism that uses at least one identifier directory, which contains a mapping between UUIDs and location-independent proxy objects, to obtain the new reference.

10. The apparatus of claim 9 wherein the directory mechanism comprises a registration mechanism that uses the remote object to perform a registration with at least one identifier directory when the remote object is first created and when a remote object is moved from one location to another.