org.gephi.graph.api

Interface GraphObserver

public interface GraphObserver

Observer over a graph to monitor changes and obtain the list of differences.

The graph observer is a mechanism used to monitor periodically changes made to the graph. This scenario is common in multi-threaded application where a thread is modifying the graph and one or multiple threads need to take action when updates are made.

Graph observer users should periodically call the hasGraphChanged() method to check the status. Each call resets the observer so if the method returns true and the graph doesn't change after that it will return false next time.

In addition of a boolean flag whether the graph has changed, an observer can collect data about the differences such as nodes added or removed. Users should call the getDiff() method after calling hasGraphChanged() to obtain the diff.

Observers should be destroyed when not needed anymore. A new observer can be obtained from the GraphModel.

Note that observer instances are not thread-safe and should not be called from multiple threads simultaneously.

See Also:

GraphModel

Method Summary

Modifier and Type	Method and Description
void	destroy() Destroys this graph observer.
GraphDiff	getDiff() Gets the graph difference.
Graph	getGraph() Gets the graph this observer is observing.
boolean	hasGraphChanged() Returns true if the graph has changed.
boolean	isDestroyed() Returns true if this observer has been destroyed.
boolean	isNew() Returns true if this observer has never got its hasGraphChanged() method called.

Method Detail

hasGraphChanged

boolean hasGraphChanged()

Returns true if the graph has changed.

Returns:

true if changed, false otherwise

getDiff

GraphDiff getDiff()

Gets the graph difference.

Returns:

the graph diff

getGraph

Graph getGraph()

Gets the graph this observer is observing.

Returns:

the graph

destroy

void destroy()

Destroys this graph observer.

isDestroyed

boolean isDestroyed()

Returns true if this observer has been destroyed.

Returns:

true if destroyed, false otherwise

isNew

boolean isNew()

Returns true if this observer has never got its hasGraphChanged() method called.

Returns:

true if new observer, false otherwise