neo4j

neo4j

Neo4j is a highly scalable native graph database that leverages data relationships as first-class entities, helping enterprises build intelligent applications to meet today’s evolving data challenges.

This module give you access to neo4j and jcypher APIs.

dependency

<dependency>
 <groupId>org.jooby</groupId>
 <artifactId>jooby-neo4j</artifactId>
 <version>1.5.1</version>
</dependency>

exports

  • GraphDatabaseService for embedded neo4j instances.
  • Driver and Session objects for remote instances
  • IDBAccess object

usage

{
  use(new Neo4j());

  get("/driver", () -> {
    // work with driver
    Driver driver = require(Driver.class);
  });

  get("/session", () -> {
    // work with session
    Session session = require(Session.class);
  });

  get("/dbaccess", () -> {
    // work with driver
    BoltDBAccess dbaccess = require(BoltDBAccess.class);
  });
}

application.conf

db.url = "bolt://localhost:7687"
 db.user = myuser
 db.password = mypassword

embedded

In addition to remote access using bolt protocol, this module provide access to embedded neo4j instances:

In memory mode:

{
  use(new Neo4j("mem"));
}

File system mode:

{
  use(new Neo4j("fs"));
}

Optionally you can specify the desired path:

{
  use(new Neo4j(Paths.get("path", "mydb")));
}

The embedded mode allow you to access GraphDatabaseService instances:

{
  use(new Neo4j("mem"));

  get("/", () -> {
    GraphDatabaseService db = require(GraphDatabaseService.class);
  });

}

As well as EmbeddedDBAccess:

{
  use(new Neo4j("mem"));

  get("/", () -> {
    EmbeddedDBAccess db = require(EmbeddedDBAccess.class);
  });

}

runtime modules

This option is available for embedded Neo4j instances and we allow to configure one or more runtime modules via .conf file:

com.graphaware.runtime.enabled = true
com.graphaware.module = [{
  class: com.graphaware.neo4j.expire.ExpirationModuleBootstrapper
  nodeExpirationProperty: _expire
}, {
  class: com.graphaware.neo4j.expire.AnotherModule
  modProp: modValue
}]

You first need to enabled the graph runtime framework by setting the com.graphaware.runtime.enabled property.

Then you need to add one or more modules under the com.graphaware.module property path.

two or more connections

Two or more connection is available by setting and installing multiples {@link Neo4j} modules:

{
  use(new Neo4j("db1"));

  use(new Neo4j("db2"));

  get("/", () -> {
    Driver db1 = require("db1", Driver.class);
    BoltDBAccess bolt1 = require("db1", BoltDBAccess.class);

    Driver db2 = require("db2", Driver.class);
    BoltDBAccess bolt2 = require("db2", BoltDBAccess.class);
  });
}

application.conf:

db1.url = "bolt://localhost:7687"
db1.user = db1user
db1.password = db1pass

db2.url = "bolt://localhost:7687"
db2.user = db2user
db2.password = db2pass

options

Neo4j options are available via .conf file:

neo4j.dbms.read_only = true
neo4j.unsupported.dbms.block_size.array_properties = 120

neo4j session store

A Session.Store powered by Neo4j.

dependency

<dependency>
 <groupId>org.jooby</groupId>
 <artifactId>jooby-neo4j</artifactId>
 <version>1.5.1</version>
</dependency>

usage

{
  session(Neo4jSessionStore.class);

  get("/", req -> {

   req.session().set("name", "jooby");
  });

}

The name attribute and value will be stored in a Neo4j database.

options

timeout

By default, a neo4j session will expire after 30 minutes. Changing the default timeout is as simple as:

# 8 hours
session.timeout = 8h
# 15 seconds
session.timeout = 15
# 120 minutes
session.timeout = 120m

It uses GraphAware’s Expire library to automatically remove expired sessions.

For embedded databases you need to configure the expire module, like:

com.graphaware.runtime.enabled = true
com.graphaware.module = [{
  class: com.graphaware.neo4j.expire.ExpirationModuleBootstrapper
  nodeExpirationProperty: _expire
}]

The Neo4jSessionStore uses the _expire attribute to evict sessions.

If you connect to a remote server make sure the expire module was installed. More information at .

If no timeout is required, use -1.

session label

It’s possible to provide the session label using the neo4j.session.label property.