Object synchronization in shared object space

Abstract

A system for synchronizing shared objects among multiple applications each running inside its own virtual machine.

1 . A system for the concurrent operation of plural computer applications, said system comprising: 
 (a) a shared object space capable of simultaneous connection with plural said applications and capable of storing at least one object accessible to at least two said applications when said plural applications are connected with said shared object space;    (b) a lock table for storing lock nodes, each said lock node being uniquely associated with a one of said plurality of applications;    (c) said at least one object having an object header capable of storing any selective one of: 
 (1) a selective said lock node;  
 (2) a reference to a selective one of said lock nodes stored in said lock table; and  
 (3) a default value other than one of said lock nodes or a reference to one of said lock nodes stored in said lock table.  
   
     
     
         2 . The system of  claim 1  where said default value is zero.  
     
     
         3 . The system of  claim 1  where said lock table is located in said shared object space.  
     
     
         4 . The system of  claim 1  where said selective one of said lock nodes operates as a cheap lock when stored in said object header.  
     
     
         5 . The system of  claim 4  where said reference to a selective one of said lock nodes stored in said lock table operate as an expensive lock when stored in said object header.  
     
     
         6 . The system of  claim 1  where said reference to a selective one of said lock nodes stored in said lock table operates as an expensive lock when stored in said object header.  
     
     
         7 . The system of  claim 6  where a said application that has a said expensive lock to a said at least one object grants said lock to another said application by swapping one of said selective one of said lock nodes, said reference, and said default value for another one of said selective one of said lock nodes, said reference, and said default value.  
     
     
         8 . The system of  claim 1  including a lock manager that controls access to at least one object by selectively swapping one of said selective one of said lock nodes, said reference, and said default value for another one of said selective one of said lock nodes, said reference, and said default value.  
     
     
         9 . The system of  claim 8  where said swap is atomic.  
     
     
         10 . The system of  claim 1  where said at least one object comprises a plurality of sub-objects, each said sub-object having a said object header.  
     
     
         11 . The system of  claim 1  where each said plural application runs in its own virtual machine.  
     
     
         12 . The system of  claim 11  where each said virtual machine is a Java virtual machine.  
     
     
         13 . The system of  claim 12  where said shared object space is connected to each said Java virtual machine by a Java native method interface.  
     
     
         14 . The system of  claim 1  where at least one of said plural applications is not an object oriented application.  
     
     
         15 . The system of  claim 14  where said at least one of said plural applications is a C application.  
     
     
         16 . A method for synchronizing access to a shared object stored in a shared object space by plural computer applications, said method comprising: 
 (a) storing at least one object in a shared object space so that said object is accessible to at least two of said plural applications when said plural applications are connected to said shared object space, said at least one object having an object header;    (b) selectively storing at least one lock node in a lock table, each said lock node being uniquely associated with a one of said plurality of applications; and    (c) storing in said object header any selective one of: 
 (1) a selective said lock node;  
 (2) a reference to a selective one of said lock node stored in said lock table; and  
 (3) a default value other than one of said lock nodes or a reference to one of said lock nodes stored in said lock table.  
   
     
     
         17 . The system of  claim 16  where said default value is zero.  
     
     
         18 . The system of  claim 16  where said lock table is located in said shared object space.  
     
     
         19 . The system of  claim 16  where said selective one of said lock nodes operates as a cheap lock when stored in said object header.  
     
     
         20 . The system of  claim 19  where said reference to a selective one of said lock nodes stored in said lock table operate as an expensive lock when stored in said object header.  
     
     
         21 . The system of  claim 16  where said reference to a selective one of said lock nodes stored in said lock table operates as an expensive lock when stored in said object header.  
     
     
         22 . The system of  claim 21  where a said application that has a said expensive lock to a said at least one object grants said lock to another said application by swapping one of said selective one of said lock nodes, said reference, and said default value for another one of said selective one of said lock nodes, said reference, and said default value.  
     
     
         23 . The system of  claim 16  including a lock manager that controls access to at least one object by selectively swapping one of said selective one of said lock nodes, said reference, and said default value for another one of said selective one of said lock nodes, said reference, and said default value.  
     
     
         24 . The system of  claim 23  where said swap is atomic.  
     
     
         25 . The system of  claim 16  where said at least one object comprises a plurality of sub-objects, each said sub-object having a said object header.  
     
     
         26 . The system of  claim 16  where each said plural application runs in its own virtual machine.  
     
     
         27 . The system of  claim 26  where each said virtual machine is a Java virtual machine.  
     
     
         28 . The system of  claim 27  where said shared object space is connected to each said Java virtual machine by a Java native method interface.  
     
     
         29 . The system of  claim 16  where at least one of said plural applications is not an object oriented application.  
     
     
         30 . The system of  claim 29  where said at least one of said plural applications is a C application.  
     
     
         31 . A system for the concurrent operation of plural computer applications, said system comprising: 
 (a) a shared object space capable of simultaneous connection with plural said applications and capable of storing at least one object accessible to at least two said applications when said plural applications are connected with said shared object space;    (b) said at least one object having a header capable of storing a lock that indicates that one of said plural applications is using the object associated with said header; and    (c) said lock being either a cheap lock or an expensive lock, said cheap lock defined as a lock that may be inserted into or removed from said header in a relatively short time with respect to said expensive lock.    
     
     
         32 . The system of  claim 31  where said header stores an expensive lock when one said application is waiting for said object associated with said header while another said application is using said object associated with said header, and said lock is a cheap lock otherwise.  
     
     
         33 . The system of  claim 31  including a lock table capable of storing a plurality of lock nodes, each said lock node being uniquely associated with a one of said plurality of applications.  
     
     
         34 . The system of  claim 33  where each said application is capable of using said at least one object through a plurality of threads and said lock table stores information as to which threads are waiting for an object being used.  
     
     
         35 . The system of  claim 34  where said threads waiting for said object being used are prioritized to determine which of said threads next gets access to said object being used.  
     
     
         36 . The system of  claim 34  where said threads waiting for said object being used are not prioritized to determine which of said threads next gets access to said object being used.  
     
     
         37 . The system of  claim 31  where said header contains a default value when said header does not contain a lock.  
     
     
         38 . The system of  claim 37  where said default value is zero.  
     
     
         39 . The system of  claim 33  where said lock table is located in said shared object space.  
     
     
         40 . The system of  claim 33  where a said application that has a said expensive lock to a said at least one object grants said lock to another said application.  
     
     
         41 . The system of  claim 33  including a lock manager that controls access to at least one object.  
     
     
         42 . The system of  claim 31  where said at least one object comprises a plurality of sub-objects, each said sub-object having a said object header.  
     
     
         43 . The system of  claim 31  where each said plural application runs in its own virtual machine.  
     
     
         44 . The system of  claim 43  where each said virtual machine is a Java virtual machine.  
     
     
         45 . The system of  claim 44  where said shared object space is connected to each said Java virtual machine by a Java native method interface.  
     
     
         46 . The system of  claim 31  where at least one of said plural applications is not an object oriented application.  
     
     
         47 . The system of  claim 46  where said at least one of said one said plural applications is a C application.