Hi Stefan,
Thanks for the discussion. Now I unterstand jackrabbits way of doing.
But in my opinion adding child nodes should not alter the parent node
itself. Just changing some properties is a state change.
i don't agree. see 7.1.4 Adding Nodes in the jsr 170 spec:
<quote>
In order to save a newly added node, save must be called either on the
Session, or on the new node's parent or higher-order ancestor
(grandparent, etc.).
</quote>
Furthermore there should be an error just in the case, that both updates
overwrite the changes of the other -> to prevent lost update problems.
In my example code it´s not the case, so I would prefer no error at all.
What do you think?
AFAIK lost updates did never happen. your testcase failed in the right
situations
but threw the wrong exceptions. i committed a fix for that problem yesterday.
IMO it now works as it should according to the jsr 170 spec.
You are right according to the spec. Let me try to explain my thoughts:
s0: read root node
s1: read root node
s0: add or remove child "c1"
s1: add or remove child "c2"
s0: rn.save()
s1: rn.save()
All this without error. Because the changes of both sessions dont
interfere.
If both sessions change the same child or attribute, there should be
thrown an InvalidItemStateException.
s0: read root node
s1: read root node
s0: set property p="hello"
s1: set property p="world"
s0: save
s1: save -> InvalidItemStateException
What do you think?
To our first problem with my testcase. I rerun the code but it still
fails with ItemNotFoundExceptions. But I dont know why.
cheers, Walter
--
Output of rerun (revision 231423):
==================================
s0: started.
s1: started.
s2: started.
s3: started.
s4: started.
s3: Exception: removing testnode
javax.jcr.InvalidItemStateException: /: the item cannot be saved because
it has been modified externally.
at
org.apache.jackrabbit.core.ItemImpl.getTransientStates(ItemImpl.java:347)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1205)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:747)
at TestSession.run(TestSession.java:62)
at java.lang.Thread.run(Unknown Source)
s3: ended.
javax.jcr.ItemNotFoundException: 545ab69b-0297-427c-a05a-217e3c8f7d88
at
org.apache.jackrabbit.core.ItemManager.createItemInstance(ItemManager.java:498)
at org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:349)
at
org.apache.jackrabbit.core.NodeImpl.internalAddChildNode(NodeImpl.java:781)
at
org.apache.jackrabbit.core.NodeImpl.internalAddNode(NodeImpl.java:725)
at
org.apache.jackrabbit.core.NodeImpl.internalAddNode(NodeImpl.java:672)
at org.apache.jackrabbit.core.NodeImpl.addNode(NodeImpl.java:1721)
at TestSession.run(TestSession.java:70)
at java.lang.Thread.run(Unknown Source)
s0: Exception: adding testnode
s0: ended.
s4: Exception: removing testnode
javax.jcr.InvalidItemStateException: /: the item cannot be saved because
it has been modified externally.
at
org.apache.jackrabbit.core.ItemImpl.getTransientStates(ItemImpl.java:347)
at org.apache.jackrabbit.core.ItemImpl.save(ItemImpl.java:1205)
at org.apache.jackrabbit.core.SessionImpl.save(SessionImpl.java:747)
at TestSession.run(TestSession.java:62)
at java.lang.Thread.run(Unknown Source)
s4: ended.
s1: Exception: adding testnode
javax.jcr.ItemNotFoundException: e170d490-b7c1-4dfa-be14-f8932162b9f7
at
org.apache.jackrabbit.core.ItemManager.createItemInstance(ItemManager.java:498)
at org.apache.jackrabbit.core.ItemManager.getItem(ItemManager.java:349)
at
org.apache.jackrabbit.core.NodeImpl.internalAddChildNode(NodeImpl.java:781)
at
org.apache.jackrabbit.core.NodeImpl.internalAddNode(NodeImpl.java:725)
at
org.apache.jackrabbit.core.NodeImpl.internalAddNode(NodeImpl.java:672)
at org.apache.jackrabbit.core.NodeImpl.addNode(NodeImpl.java:1721)
at TestSession.run(TestSession.java:70)
at java.lang.Thread.run(Unknown Source)
s1: ended.
..........s2: ended.
