Event Implementation - datablend/blueprints GitHub Wiki
<dependency>
<groupId>com.tinkerpop.blueprints</groupId>
<artifactId>blueprints-core</artifactId>
<version>??</version>
</dependency>EventGraph and EventIndexableGraph wrap any Graph or IndexableGraph, respectively. The purpose of an EventGraph is to raise events to one or more GraphChangedListener as changes to the underlying Graph occur. The obvious limitation is that events will only be raised to listeners if the changes to the Graph occur within the same process.
The following events are raised:
- New vertex
- New edge
- Vertex property changed
- Edge property changed
- Vertex property removed
- Edge property removed
- Vertex removed
- Edge removed
- Graph cleared
To start processing events from a Graph first implement the GraphChangedListener interface. An example of this implementation is the ConsoleGraphChangedListener which writes output to the console for each event.
To add a listener to the EventGraph:
EventGraph graph = new EventGraph(TinkerGraphFactory.createTinkerGraph());
graph.addListener(new ConsoleGraphChangedListener(graph));
Vertex v = graph.addVertex(100);
v.setProperty("name", "noname");
for (Edge edge : graph.getEdges()) {
edge.removeProperty("weight");
}
graph.clear();The following output would appear in the console:
Vertex [v[100]] added to graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Vertex [v[4]] property [name] set to value of [noname] in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[10][4-created->5]] property [weight] with value of [1.0] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[7][1-knows->2]] property [weight] with value of [0.5] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[9][1-created->3]] property [weight] with value of [0.4] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[8][1-knows->4]] property [weight] with value of [1.0] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[11][4-created->3]] property [weight] with value of [0.4] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Edge [e[12][6-created->3]] property [weight] with value of [0.2] removed in graph [eventgraph[tinkergraph[vertices:6 edges:6]]]
Graph [eventgraph[tinkergraph[vertices:6 edges:6]]] cleared.