org.apache.jackrabbit.oak.plugins.observation

Interface EventHandler

All Known Implementing Classes:

DefaultEventHandler, FilteredHandler

public interface EventHandler

Handler of content change events. Used to decouple processing of changes from the content diff logic that detects them.

As the content diff recurses down the content tree, it will call the getChildHandler(String, NodeState, NodeState) method to specialize the handler instance for each node under which changes are detected. The other handler methods always apply to the properties and direct children of the node for which that handler instance is specialized. The handler is expected to keep track of contextual information like the path or identifier of the current node based on the sequence of those specialization calls.

The events belonging to this instance should be delivered before events to other instance deeper down the tree are delivered.

All names and paths passed to handler methods use unmapped Oak names.

Method Summary

Modifier and Type	Method and Description
void	enter(NodeState before, NodeState after) Called before the given before and after states are compared.
@Nullable EventHandler	getChildHandler(java.lang.String name, NodeState before, NodeState after) Returns a handler of events within the given child node, or null if changes within that child are not to be processed.
void	leave(NodeState before, NodeState after) Called after the given before and after states are compared.
void	nodeAdded(java.lang.String name, NodeState after) Notification for an added node
void	nodeDeleted(java.lang.String name, NodeState before) Notification for a deleted node
void	nodeMoved(java.lang.String sourcePath, java.lang.String name, NodeState moved) Notification for a moved node
void	nodeReordered(java.lang.String destName, java.lang.String name, NodeState reordered) Notification for a reordered node
void	propertyAdded(PropertyState after) Notification for an added property
void	propertyChanged(PropertyState before, PropertyState after) Notification for a changed property
void	propertyDeleted(PropertyState before) Notification for a deleted property

Method Detail

enter

void enter(NodeState before,
           NodeState after)

Called before the given before and after states are compared. The implementation can use this method to initialize any internal state needed for processing the results of the comparison.

Parameters:

before - before state, non-existent if this node was added

after - after state, non-existent if this node was removed

leave

void leave(NodeState before,
           NodeState after)

Called after the given before and after states are compared. The implementation can use this method to post-process information collected during the content diff.

Parameters:

before - before state, non-existent if this node was added

after - after state, non-existent if this node was removed

getChildHandler

@Nullable
@Nullable EventHandler getChildHandler(java.lang.String name,
                                                 NodeState before,
                                                 NodeState after)

Returns a handler of events within the given child node, or null if changes within that child are not to be processed.

Parameters:

name - name of the child node

before - before state of the child node, possibly non-existent

after - after state of the child node, possibly non-existent

Returns:

handler of events within the child node, or null

propertyAdded

void propertyAdded(PropertyState after)

Notification for an added property

Parameters:

after - added property

propertyChanged

void propertyChanged(PropertyState before,
                     PropertyState after)

Notification for a changed property

Parameters:

before - property before the change

after - property after the change

propertyDeleted

void propertyDeleted(PropertyState before)

Notification for a deleted property

Parameters:

before - deleted property

nodeAdded

void nodeAdded(java.lang.String name,
               NodeState after)

Notification for an added node

Parameters:

name - name of the node

after - added node

nodeDeleted

void nodeDeleted(java.lang.String name,
                 NodeState before)

Notification for a deleted node

Parameters:

name - name of the deleted node

before - deleted node

nodeMoved

void nodeMoved(java.lang.String sourcePath,
               java.lang.String name,
               NodeState moved)

Notification for a moved node

Parameters:

sourcePath - source of the moved node

name - name of the moved node

moved - moved node

nodeReordered

void nodeReordered(java.lang.String destName,
                   java.lang.String name,
                   NodeState reordered)

Notification for a reordered node

Parameters:

destName - name of the orderBefore() destination node

name - name of the moved node

reordered - moved node