Patent ID: 7653629

Claim:
A hierarchal locking system embodied on one or more computer readable media for accessing resources of a data structure relating to electronic ink strokes, comprising: one or more resources that are nodes of a tree structure; a parser for analyzing one or more electronic ink strokes to produce the tree structure, wherein the tree structure represents a relationship between the one or more electronic ink strokes, and wherein each node contains data corresponding to the one or more electronic ink strokes; high priority locks for locking at least a portion of the nodes, such that if a first high priority lock request attempts to lock one or more of the nodes for a write operation when access to the one or more nodes is already restricted by a conflicting second high priority lock, or if a first high priority lock request attempts to lock one or more of the nodes for a read operation when access to the one or more nodes is already restricted by a conflicting second high priority lock for a write operation, then the first high priority lock request will fail; and low priority locks having a low priority for locking at least a portion of the nodes, such that if a first low priority lock request attempts to lock one or more of the nodes for a write operation when access to the one or more nodes is already restricted by a conflicting second low priority lock or by a high priority lock, or if a first low priority lock request attempts to lock one or more of the nodes for a read operation when access to the one or more nodes is already restricted by a conflicting second low priority lock for a write operation or by a high priority lock for a write operation, then the first low priority lock request will fail.