On Thu, Dec 29, 2011 at 6:19 PM, Michael Dürig mic...@gmail.com wrote:
Hi,
Over at the sandbox [1] I implemented a new (AFAIK) approach for the JCR
transient space. The gist of it is in the ChangeTree class [2] while some
more Microkernel specific things are factored out into the TransientSpace
class [3].
great work! it's good to see a fresh take on jcr client implementation.
some comments from the peanut gallery follow inline ;)
The key idea is to only store changes to the node hierarchy in the
ChangeTree and to do that in a way which allows reconstructing a list of
corresponding operations (add, remove, move for nodes and set for
properties) from that ChangeTree. This differs from other implementations
where the list of operations is kept *together* with the modified hierarchy.
Furthermore with the ChangeTree approach no untouched nodes need to be kept
in memory.
that's also true for the existing jackrabbit-core implementation.
Finally the list of operations reconstructed from a ChangeTree is
minimal. That is, all cancelling operations are reduced as much as possible:
same here, jackrabbit-core does consolidate transient changes as well.
cheers
stefan
add followed by remove of the same item results in no operations, add
followed by move of the same node results in the node being added at the
target of the move, move followed by remove of a node results in the node
being removed at the source of the move and move followed by another move of
a node results in a single move from the original source to the eventual
target. More details are in the class comment of ChangeTree and even more
details in the implementation ;-)
Michael
[1] http://svn.apache.org/viewvc/jackrabbit/sandbox/jackrabbit-microkernel/
[2]
http://svn.apache.org/viewvc/jackrabbit/sandbox/jackrabbit-microkernel/src/main/java/org/apache/jackrabbit/state/ChangeTree.java?view=markup
[3]
http://svn.apache.org/viewvc/jackrabbit/sandbox/jackrabbit-microkernel/src/main/java/org/apache/jackrabbit/state/TransientSpace.java?view=markup
