The navigation service provides a low-level API for managing navigation state between the portal and MOP. It focuses on state management, model-less design, and performance. It allows loading, updating, rebasing, and saving navigation fragments. Operations generate changes to synchronize data models. Node filtering supports access control and use case filtering. The navigation controller decouples URL handling from portal requests. Future work includes applying the model to pages and layouts.

1. Navigation
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2. Navigation service
• Low level API between the portal and the
MOP
• A data controller focusing on
– State management
• Historical problem
• Concurrent load/save/merge
• Correctness
– Model-less design
• Model API easy to plug
• Change notifications
– Performances
• Load what is necessary
• Built-in cache
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3. Navigation service operations
• Load
– Load a fragment of a larger tree
– Create a detached snapshot that can be modified
• Update
– Update a fragment with the most recent state
– Suppose no transient changes
• Rebase
– Same as update but cope with changes
• Save
– Same as rebase but save to the persistent store
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4. Data life cycle and flow
Rebased
state
Persistent
state
Checkout
state
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5. Operation workflow
Update
Rebase
Save
Get
fresh
copy
Rebase
changes
Save
to
storage
Update
checkout
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6. Conflict resolution
• The rebase operations takes a list of changes
and replay on another tree, each change
– Operate on same input  OK
– Operate on different output  merge
• Conflict solved example with (a,b)
– User 1 insert 1: (a,1,b)
– User 2 insert 2 and save concurrently: (a,2,b)
– User 1 saves: (a,1,2,b)
• Conflict unsolved example with (a)
– User 1 insert 1: (a,a/1)
– User 2 removes a: ()
– User 1 saves: failure
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7. Model-less design
• Navigation are used for different purposes
– Internal UserNode objects
– GateIn API
• NodeContext<N>
– <N> is the model / API : cares about usage
– NodeContext : cares about state
• The NodeModel<N> factory
– Provided by the client
– Used by the service
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8. Tree scope
• Required by most operation performed on
the tree
• Defines what is loaded
– Scope.SINGLE
– Scope.CHILDREN
– Scope.GRANDCHILDREN
– Scope.ALL
• Plugable eventually (visitor)
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9. Node changes
• Operations modifying the
NodeContext<N> generate a flow of
changes
• Used to synchronize an existing data
model based on <N>
– Used by the navigation editor to update the
state
– Used by navigation portlet to determine if the
navigation should be refreshed
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10. Node filtering
• The service has a built in node filtering
capabilities
– Access control (inferred by underlying page)
– Time based: TEMPORAL nodes
– Use case based
• Navigation portlets don’t display SYSTEM nodes
• Navigation editor displays SYSTEM node but only
for administrators
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11. Internal API
• UserPortal
– Models the relationship between a user and a
portal
– Replaces the UserPortalConfig object
– Built on top of the NavigationService
– Defines notion of UserPortalFilter to filter
navigations
– Resolve path to nodes
• Future legacy
• Emulation will be performed to redirect to correct
page
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12. Internal API
• UserNode
– The <N> of UserContext
– Translates the localizable values (label)
– Remove notion of stored URI, instead URI is
rebuilt from its path
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13. Navigation controller
• An effort started 6 months ago and mostly
finished (85%)
– Decouple the request URL and the handling in
the portal in a flexible and configurable
manner
– Associate a unique resource to an URL (REST)
• Will be merged after the new navigation
service is done
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14. URL handling
• Navigation controller provides an API for
generating URL from a resource
• In particular the portal needs to generate
URL for a given navigation node
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15. Performances concerns
• On default navigation, SQL activity was
reduced by ½
• On large navigation, SQL activity is
dominated by the first 2 levels instead of
the whole navigation previously
• Other fixes were applied to handle
numerous pages
– Better pagination support
– Functional changes
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16. Roadmap
• Navigation Service
– developed against exogtn 3.1.7-REBASED
(very close to EPP 5.1)
– ported to exogtn 3.2.x for 3.2.0-beta3 (end of
June) and GateIn trunk
• Navigation i18n
– Will be part of 3.2.0-beta3 and GateIn trunk
• Navigation controller
– The current work will be remerged after
3.2.0-beta3 and finished
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17. Next steps
• Apply the same model to pages and
layouts after GateIn 3.2
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