public Node getTownByName(String name) {
Transaction tx = db.beginTx();
Node result2 = null;
Node ss;
try {
ss = indexToNode(id, "geo");
// System.out.println("x22222");
// System.out.println("1111");
Traverser traverser1 =
ss.traverse(
Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
admin_rel.PROVINCE,
Direction.OUTGOING);
// System.out.println("x33333");
outerloop:
for (Node f : traverser1) {
Traverser traverser2 =
f.traverse(
Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
admin_rel.DISTRICT,
Direction.OUTGOING);
for (Node f2 : traverser2) {
Traverser traverser3 =
f2.traverse(
Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
geo_rel.PRIMARY_NODE,
Direction.OUTGOING);
for (Node f3 : traverser3) {
if (f3.getProperty("name").equals(name)) {
// System.out.println("here="+f3);
// System.out.println("xxxs="+f3.getProperty("postalcode"));
result2 = f3;
break outerloop;
}
}
}
}
tx.success();
} finally {
tx.finish();
}
return result2;
}
@Test
public void testSimpleGraph() throws Exception {
GraphDatabaseService neo = dbRule.getGraphDatabaseService();
Transaction tx = neo.beginTx();
try {
final Node emil = neo.createNode();
emil.setProperty("name", "Emil Eifrém");
emil.setProperty("age", 30);
final Node tobias = neo.createNode();
tobias.setProperty("name", "Tobias \"thobe\" Ivarsson");
tobias.setProperty("age", 23);
tobias.setProperty("hours", new int[] {10, 10, 4, 4, 0});
final Node johan = neo.createNode();
johan.setProperty("!<>)", "!<>)");
johan.setProperty("name", "!<>Johan '\\n00b' !<>Svensson");
final Relationship emilKNOWStobias = emil.createRelationshipTo(tobias, type.KNOWS);
emilKNOWStobias.setProperty("since", "2003-08-17");
final Relationship johanKNOWSemil = johan.createRelationshipTo(emil, type.KNOWS);
final Relationship tobiasKNOWSjohan = tobias.createRelationshipTo(johan, type.KNOWS);
final Relationship tobiasWORKS_FORemil = tobias.createRelationshipTo(emil, type.WORKS_FOR);
OutputStream out = new ByteArrayOutputStream();
GraphvizWriter writer = new GraphvizWriter();
writer.emit(
out,
Walker.crosscut(
emil.traverse(
Order.DEPTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL,
type.KNOWS,
Direction.BOTH,
type.WORKS_FOR,
Direction.BOTH),
type.KNOWS,
type.WORKS_FOR));
tx.success();
out.toString();
} finally {
tx.finish();
}
}
/**
* This is an example showing a hierarchy of roles. What's interesting is that a tree is not
* sufficient for storing this structure, as elaborated below.
*
* <p>image::roles.png[scaledwidth="100%"]
*
* <p>This is an implementation of an example found in the article
* http://www.codeproject.com/Articles/22824/A-Model-to-Represent-Directed-Acyclic-Graphs-DAG-o[A
* Model to Represent Directed Acyclic Graphs (DAG) on SQL Databases] by
* http://www.codeproject.com/script/Articles/MemberArticles.aspx?amid=274518[Kemal Erdogan]. The
* article discusses how to store http://en.wikipedia.org/wiki/Directed_acyclic_graph[ directed
* acyclic graphs] (DAGs) in SQL based DBs. DAGs are almost trees, but with a twist: it may be
* possible to reach the same node through different paths. Trees are restricted from this
* possibility, which makes them much easier to handle. In our case it is "Ali" and "Engin", as
* they are both admins and users and thus reachable through these group nodes. Reality often
* looks this way and can't be captured by tree structures.
*
* <p>In the article an SQL Stored Procedure solution is provided. The main idea, that also have
* some support from scientists, is to pre-calculate all possible (transitive) paths. Pros and
* cons of this approach:
*
* <p>* decent performance on read * low performance on insert * wastes _lots_ of space * relies
* on stored procedures
*
* <p>In Neo4j storing the roles is trivial. In this case we use +PART_OF+ (green edges)
* relationships to model the group hierarchy and +MEMBER_OF+ (blue edges) to model membership in
* groups. We also connect the top level groups to the reference node by +ROOT+ relationships.
* This gives us a useful partitioning of the graph. Neo4j has no predefined relationship types,
* you are free to create any relationship types and give them any semantics you want.
*
* <p>Lets now have a look at how to retrieve information from the graph. The Java code is using
* the Neo4j Traversal API (see <<tutorial-traversal-java-api>>), the queries are done using
* <<cypher-query-lang, Cypher>>.
*
* <p>== Get the admins == @@get-admins
*
* <p>resulting in the output @@o-get-admins
*
* <p>The result is collected from the traverser using this code: @@read-traverser
*
* <p>In Cypher, a similar query would be: @@query-get-admins
*
* <p>resulting in: @@o-query-get-admins
*
* <p>== Get the group memberships of a user ==
*
* <p>Using the Neo4j Java Traversal API, this query looks like: @@get-user-memberships
*
* <p>resuling in: @@o-get-user-memberships
*
* <p>In Cypher: @@query-get-user-memberships @@o-query-get-user-memberships
*
* <p>== Get all groups ==
*
* <p>In Java: @@get-groups
*
* <p>resulting in: @@o-get-groups
*
* <p>In Cypher: @@query-get-groups @@o-query-get-groups
*
* <p>== Get all members of all groups ==
*
* <p>Now, let's try to find all users in the system being part of any group.
*
* <p>in Java: @@get-members @@o-get-members
*
* <p>In Cypher, this looks like: @@query-get-members
*
* <p>and results in the following output: @@o-query-get-members
*
* <p>As seen above, querying even more complex scenarios can be done using comparatively short
* constructs in Java and other query mechanisms.
*/
@Test
@Documented
@Graph({
"Admins ROOT Reference_Node",
"Users ROOT Reference_Node",
"HelpDesk PART_OF Admins",
"Managers PART_OF Users",
"Technicians PART_OF Users",
"ABCTechnicians PART_OF Technicians",
"Ali MEMBER_OF Users",
"Ali MEMBER_OF Admins",
"Engin MEMBER_OF Users",
"Engin MEMBER_OF HelpDesk",
"Demet MEMBER_OF HelpDesk",
"Burcu MEMBER_OF Users",
"Can MEMBER_OF Users",
"Gul MEMBER_OF Managers",
"Fuat MEMBER_OF Managers",
"Hakan MEMBER_OF Technicians",
"Irmak MEMBER_OF Technicians",
"Jale MEMBER_OF ABCTechnicians"
})
public void user_roles_in_graphs() {
// get Admins
gen.get()
.addTestSourceSnippets(
this.getClass(),
"get-admins",
"get-user-memberships",
"get-groups",
"get-members",
"read-traverser");
System.out.println("All admins:");
// START SNIPPET: get-admins
Node admins = getNodeByName("Admins");
Traverser traverser =
admins.traverse(
Traverser.Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
RoleRels.PART_OF,
Direction.INCOMING,
RoleRels.MEMBER_OF,
Direction.INCOMING);
// END SNIPPET: get-admins
gen.get().addSnippet("o-get-admins", createOutputSnippet(traverserToString(traverser)));
String query =
"start admins=node("
+ admins.getId()
+ ") match admins<-[:PART_OF*0..]-group<-[:MEMBER_OF]-user return user.name, group.name";
gen.get().addSnippet("query-get-admins", createCypherSnippet(query));
String result = engine.execute(query).dumpToString();
assertTrue(result.contains("Engin"));
gen.get().addSnippet("o-query-get-admins", createQueryResultSnippet(result));
// Jale's memberships
// START SNIPPET: get-user-memberships
Node jale = getNodeByName("Jale");
traverser =
jale.traverse(
Traverser.Order.DEPTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
RoleRels.MEMBER_OF,
Direction.OUTGOING,
RoleRels.PART_OF,
Direction.OUTGOING);
// END SNIPPET: get-user-memberships
gen.get()
.addSnippet("o-get-user-memberships", createOutputSnippet(traverserToString(traverser)));
query =
"start jale=node("
+ jale.getId()
+ ") match jale-[:MEMBER_OF]->()-[:PART_OF*0..]->group return group.name";
gen.get().addSnippet("query-get-user-memberships", createCypherSnippet(query));
result = engine.execute(query).dumpToString();
assertTrue(result.contains("Users"));
gen.get().addSnippet("o-query-get-user-memberships", createQueryResultSnippet(result));
// get all groups
// START SNIPPET: get-groups
Node referenceNode = getNodeByName("Reference_Node");
traverser =
referenceNode.traverse(
Traverser.Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
ReturnableEvaluator.ALL_BUT_START_NODE,
RoleRels.ROOT,
Direction.INCOMING,
RoleRels.PART_OF,
Direction.INCOMING);
// END SNIPPET: get-groups
gen.get().addSnippet("o-get-groups", createOutputSnippet(traverserToString(traverser)));
query =
"start refNode=node("
+ referenceNode.getId()
+ ") match refNode<-[:ROOT]->()<-[:PART_OF*0..]-group return group.name";
gen.get().addSnippet("query-get-groups", createCypherSnippet(query));
result = engine.execute(query).dumpToString();
assertTrue(result.contains("Users"));
gen.get().addSnippet("o-query-get-groups", createQueryResultSnippet(result));
// get all members
// START SNIPPET: get-members
traverser =
referenceNode.traverse(
Traverser.Order.BREADTH_FIRST,
StopEvaluator.END_OF_GRAPH,
new ReturnableEvaluator() {
@Override
public boolean isReturnableNode(TraversalPosition currentPos) {
if (currentPos.isStartNode()) {
return false;
}
Relationship rel = currentPos.lastRelationshipTraversed();
return rel.isType(RoleRels.MEMBER_OF);
}
},
RoleRels.ROOT,
Direction.INCOMING,
RoleRels.PART_OF,
Direction.INCOMING,
RoleRels.MEMBER_OF,
Direction.INCOMING);
// END SNIPPET: get-members
gen.get().addSnippet("o-get-members", createOutputSnippet(traverserToString(traverser)));
query =
"start refNode=node("
+ referenceNode.getId()
+ ") "
+ "match refNode<-[:ROOT]->root, p=root<-[PART_OF*0..]-()<-[:MEMBER_OF]-user "
+ "return user.name, min(length(p)) "
+ "order by min(length(p)), user.name";
gen.get().addSnippet("query-get-members", createCypherSnippet(query));
result = engine.execute(query).dumpToString();
assertTrue(result.contains("Engin"));
gen.get().addSnippet("o-query-get-members", createQueryResultSnippet(result));
/* more advanced example
query = "start refNode=node("+ referenceNode.getId() +") " +
"match p=refNode<-[:ROOT]->parent<-[:PART_OF*0..]-group, group<-[:MEMBER_OF]-user return group.name, user.name, LENGTH(p) " +
"order by LENGTH(p)";
*/
}
