info.dmtree
Interface DmtEvent

public interface DmtEvent

Event class storing the details of a change in the tree. DmtEvent is used by DmtAdmin to notify registered EventListeners about important changes. Events are generated after every successful DMT change, and also when sessions are opened or closed. If a DmtSession is opened in atomic mode, DMT events are only sent when the session is committed, when the changes are actually performed.

An event is generated for each group of nodes added, deleted, replaced, renamed or copied, in this order. Events are also generated when sessions are opened and closed.

The type of the event describes the change that triggered the event delivery. Each event carries the unique identifier of the session in which the described change happened. The events describing changes in the DMT carry the list of affected nodes. In case of COPIED or RENAMED events, the event carries the list of new nodes as well.

When a DmtEvent is delivered to a listener, the event contains only those node URIs that the listener has access to. This access control decision is based on the principal specified when the listener was registered:

• If the listener was registered specifying an explicit principal, using the DmtAdmin.addEventListener(String, int, String, DmtEventListener) method, then the target node ACLs should be checked for providing GET access to the specified principal;
• When the listener was registered without an explicit principal then the listener needs GET DmtPermission for the corresponding node.

Field Summary

static int	ADDED Event type indicating nodes that were added.
static int	COPIED Event type indicating nodes that were copied.
static int	DELETED Event type indicating nodes that were deleted.
static int	RENAMED Event type indicating nodes that were renamed.
static int	REPLACED Event type indicating nodes that were replaced.
static int	SESSION_CLOSED Event type indicating that a session was closed.
static int	SESSION_OPENED Event type indicating that a new session was opened.

Method Summary

java.lang.String[]	getNewNodes() This method can be used to query the new nodes, when the type of the event is COPIED or RENAMED.
java.lang.String[]	getNodes() This method can be used to query the subject nodes of this event.
int	getSessionId() This method returns the identifier of the session in which this event took place.
int	getType() This method returns the type of this event.

Field Detail

ADDED

public static final int ADDED

Event type indicating nodes that were added.

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Constant Field Values

COPIED

public static final int COPIED

Event type indicating nodes that were copied.

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Constant Field Values

DELETED

public static final int DELETED

Event type indicating nodes that were deleted.

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Constant Field Values

RENAMED

public static final int RENAMED

Event type indicating nodes that were renamed.

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Constant Field Values

REPLACED

public static final int REPLACED

Event type indicating nodes that were replaced.

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Constant Field Values

SESSION_OPENED

public static final int SESSION_OPENED

Event type indicating that a new session was opened.

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Constant Field Values

SESSION_CLOSED

public static final int SESSION_CLOSED

Event type indicating that a session was closed. This type of event is sent when the session is closed by the client or becomes inactive for any other reason (session timeout, fatal errors in business methods, etc.).

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Constant Field Values

Method Detail

getType

public int getType()

This method returns the type of this event.

Returns:

the type of this event.

getSessionId

public int getSessionId()

This method returns the identifier of the session in which this event took place. The ID is guaranteed to be unique on a machine.

Returns:

the unique indetifier of the session that triggered the event

getNodes

public java.lang.String[] getNodes()

This method can be used to query the subject nodes of this event. The method returns null for SESSION_OPENED and SESSION_CLOSED.

The method returns only those affected nodes that the caller has the GET permission for (or in case of COPIED or RENAMED events, where the caller has GET permissions for either the source or the destination nodes). Therefore, it is possible that the method returns an empty array. All returned URIs are absolute.

Returns:

the array of affected nodes

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getNewNodes()

getNewNodes

public java.lang.String[] getNewNodes()

This method can be used to query the new nodes, when the type of the event is COPIED or RENAMED. For all other event types this method returns null.

The array returned by this method runs parallel to the array returned by getNodes(), the elements in the two arrays contain the source and destination URIs for the renamed or copied nodes in the same order. All returned URIs are absolute.

This method returns only those nodes where the caller has the GET permission for the source or destination node of the operation. Therefore, it is possible that the method returns an empty array.

Returns:

the array of newly created nodes