With ArangoDB 2.2 the new graph API was released featuring multi collection graphs (see blog). With the new version (2.2.1) of arangodb-java-driver the new graph API is supported. In the following you can find a small example of creating a graph with Java.
For the import via maven and configuring the driver, please read the Basics and Driver Setup. For the following we assume, that arangodbDriver is a configured instance of the driver.
So let’s start the whole thing…
In the database we need a graph containing collections for the vertices and edges (defined in edge definitions).
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// Edge definitions of the graph List<EdgeDefinitionEntity> edgeDefinitions = new ArrayList<EdgeDefinitionEntity>(); // We start with one edge definition: EdgeDefinitionEntity edgeDefHasWritten = new EdgeDefinitionEntity(); // Define the edge collection... edgeDefHasWritten.setCollection("HasWritten"); // ... and the vertex collection(s) where an edge starts... List<String> from = new ArrayList<String>(); from.add("Person"); edgeDefHasWritten.setFrom(from); // ... and ends. List<String> to = new ArrayList<String>(); to.add("Publication"); edgeDefHasWritten.setTo(to); // add the edge definition to the list edgeDefinitions.add(edgeDefHasWritten); // We do not need any orphan collections, so this is just an empty list List<String> orphanCollections = new ArrayList<String>(); // Create the graph: GraphEntity graphAcademical = arangoDriver.createGraph("Academical", edgeDefinitions, orphanCollections, true); |
Now we have a graph Academical where edges are defined from vertex collection Person to vertex collection Publication and stored in edge collection HasWritten. Collections will be created automatically if they do not already exist. Let’s add another edge definition to the graph:
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EdgeDefinitionEntity edgeDefHasCited = new EdgeDefinitionEntity(); edgeDefHasCited.setCollection("HasCited"); from.clear(); from.add("Publication"); edgeDefHasCited.setFrom(from); to.clear(); to.add("Publication"); edgeDefHasCited.setTo(to); // add the new definition to the existing graph: arangoDriver.graphCreateEdgeDefinition(graphAcademical.getName(), edgeDefHasCited); |
In this second part only the collection HasCited is created, the collection Publication already exists and was used automatically.
Let us play a little with our graph. A first step would be, to fill it with vertices and edges. Therefore we should define, which information a vertex contains. So let’s define some classes for the different vertices:
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class Person { String name; String title; public Person(String name, String title) { this.name = name; this.title = title; } // getter and setter ... } class Publication { String title; String isbn; int pages; public Publication(String title, String isbn, int pages) { this.title = title; this.isbn = isbn; this.pages = pages; } // getter and setter ... } |
Fill the graph with vertices…
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DocumentEntity<Person> person1 = arangoDriver.graphCreateVertex("Academical", "Person", new Person("Bob", "Dr"), true); DocumentEntity<Person> person2 = arangoDriver.graphCreateVertex("Academical", "Person", new Person("Floyd", "master of arts"), true); DocumentEntity<Publication> publication1 = arangoDriver.graphCreateVertex("Academical", "Publication", new Publication("Surgery for dummies", "1-234-1", 42), true); DocumentEntity<Publication> publication2 = arangoDriver.graphCreateVertex("Academical", "Publication", new Publication("Relaxing while working", "5-678-x", 815), true); DocumentEntity<Publication> publication3 = arangoDriver.graphCreateVertex("Academical", "Publication", new Publication("Infrasound in art and science", "7-081-5", 60), true); |
… and edges:
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arangoDriver.graphCreateEdge("Academical", "HasWritten", null, person1.getDocumentHandle(), publication1.getDocumentHandle()); arangoDriver.graphCreateEdge("Academical", "HasWritten", null, person2.getDocumentHandle(), publication2.getDocumentHandle()); arangoDriver.graphCreateEdge("Academical", "HasWritten", null, person2.getDocumentHandle(), publication3.getDocumentHandle()); arangoDriver.graphCreateEdge("Academical", "HasCited", null, publication1.getDocumentHandle(), publication3.getDocumentHandle()); arangoDriver.graphCreateEdge("Academical", "HasCited", null, publication1.getDocumentHandle(), publication2.getDocumentHandle()); |
Click here for part 2.
