Conflict resolution for collaborative work system

A computer-implemented method of maintaining consistency of a plurality of data objects, each data object being maintained by a different one of a plurality of computers that are operatively connected to each other by a network, and the method being performed at a first one of the plurality of computers to maintain a first one of the data objects, the method comprising:

• receiving a synchronization message from a second one of the plurality of computers, the synchronization message comprising:
• a current operation parameter comprising data identifying a first operation that was executed by the second computer, data required for execution of the first operation at the first computer to manipulate the first data object in a manner effecting synchronization of the first and the second computer, a first execution stage parameter identifying an operational stage at which the first operation was executed by the second computer, and a value identifying the second computer,
• a previous operation parameter comprising a parameter identifying a second operation that was executed by the second computer prior to execution of the first operation, a second execution stage parameter identifying an operational stage at which said second operation was executed at the second computer, and an identity of a computer originating said second operation,
• a parameter identifying a unique priority level of the second computer with respect to others of the plurality of computers;
• and
• updating the first one of the data objects by executing the operation identified by the current operation parameter at the first computer when the first computer is at a correct execution stage.

A computer system comprising:

• a processor;
• a network interface coupled to the processor and operatively coupling the computer system to a plurality of other computer systems;
• a memory coupled to the processor and storing a first data object, said first data object being a local replica of data replicated at others of the plurality of computers;
• a local state module configured to record data effecting manipulations of the first data object, said local state module comprising memory recording operations effecting synchronization of the first data object;
• and
• a consistency module coupled to the processor and memory and operating to maintain consistency of the first data object with replicas of the data object that are stored at the other computer systems, said maintaining being performed based on processing of received synchronization messages, each received synchronization message comprising:
• a current operation parameter comprising data identifying a first operation that was executed by another computer, data required for execution of the first operation so as to manipulate the first data object in a manner effecting synchronization of the first data object with a data object stored at the other computer, a first execution stage parameter identifying an operational stage at which the first operation was executed by the other computer, and a value identifying the other computer, and
• a previous operation parameter comprising a parameter identifying a second operation that was executed by the other computer prior to execution of the first operation, a second execution stage parameter identifying an operational stage at which said second operation was executed at the other computer, and an identity of a computer originating said second operation,