How to use graph.getVertices() get specific vertices, Java , Oriendtdb - orientdb

Question

How to use graph.getVertices() get specific vertices.
My Class name is Station has Extended V(Vertex) .
category' (datatype is LINK)is property of Station
Category's can be '#12:13' or '#12:14' or '#12:15'
I want to use graph.getVertices() JAVA to get specific category.
Something like :
graph.getVertices("Station category = '#12:13'");
graph.getVertices("Excluded Station Category = '#12:13'");
Any suggestion?

Answer 1

I used this simple structure to try your case (category is of type LINK):
CLASSES:
and I retrieved the results you're looking for with this code:
JAVA CODE:
package yourPackage;
import java.io.IOException;
import com.orientechnologies.orient.client.remote.OServerAdmin;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.blueprints.impls.orient.OrientGraph;
public class YourClass{
private static String remote = "remote:localhost/";
public static void main(String[] args) {
String DBname = "yourDBname";
String currentPath = remote + DBname;
OServerAdmin serverAdmin;
try {
serverAdmin = new OServerAdmin(currentPath).connect("root", "root");
if (serverAdmin.existsDatabase()) {
OrientGraph g = new OrientGraph(currentPath);
String yourRid = "#13:0";
Iterable<Vertex> targets = g.getVerticesOfClass("Station");
System.out.println("Category #rid = " + yourRid);
System.out.println();
for (Vertex target : targets) {
Vertex category = target.getProperty("category");
if (category.getId().toString().equals(yourRid)) {
System.out.println("Matched Station: " + target.getProperty("name") + " Category: "
+ category.getProperty("name") + " (" + category.getId() + ")");
System.out.println();
} else {
System.out.println("Excluded Station: " + target.getProperty("name") + " Category: "
+ category.getProperty("name") + " (" + category.getId() + ")");
}
}
}
else {
System.out.println("Database " + DBname + " not found");
}
serverAdmin.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
OUTPUT:
Category #rid = #13:0
Matched Station: First Category: category 1 (#13:0)
Excluded Station: Second Category: category 2 (#13:1)
Excluded Station: Third Category: category 3 (#13:2)
Hope it helps

Answer 2

to get all vertices of Station class, try:
g.V('_class','Station')
or to filter by a category field
g.V('_class','Station').has('category','catvalue 123')
or if you have multiple to match:
g.V('_class', 'Station').has('category', T.in,['12:13','12:14'])
or for specific Id
g.v('12:13')
to find if an edge exists between 2 vertices, you can use:
g.v(stationVtxId).outE('edge_label').sideEffect{x=it}.inV.filter{it == g.v(catVtxId)}.back(2)

Answer 3

I used an index on the property category of the class Station
create class Station extends V
create class Category extends V
create property Station.name STRING
create property Station.category LINK Category
create property Category.name STRING
create index Station.category ON Station (category) NOTUNIQUE
insert into category(name) values ("category A") // 13:0
insert into category(name) values ("category B") // 13:1
insert into Station(name,category) values ("Station 1",#13:0)
insert into Station(name,category) values ("Station 2",#13:1)
JAVA