Script API

The script API handles Gremlin-groovy requests provided as plain Java strings. To execute a script, wrap it into a ScriptGraphStatement and pass it to the session:

CqlSession session = CqlSession.builder().build();

String groovyScript = "system.graph('demo').ifNotExists().create()";
ScriptGraphStatement statement = ScriptGraphStatement.newInstance(groovyScript);
session.execute(statement);

Creating script statements

Factory method

As demonstrated above, the simplest way to create a script statement is to pass the Gremlin-groovy string to ScriptGraphStatement.newInstance.

The default implementation returned by the driver is immutable; if you call additional methods on the statement – for example to set options – each method call will create a new copy:

ScriptGraphStatement statement =
    ScriptGraphStatement.newInstance("system.graph('demo').ifNotExists().create()");
ScriptGraphStatement statement2 = statement.setTimeout(Duration.ofSeconds(10));

assert statement2 != statement;

Immutability is good because it makes statements inherently thread-safe: you can share them in your application and access them concurrently without any risk.

On the other hand, it means a lot of intermediary copies if you often call methods on your statements. Modern VMs are normally good at dealing with such short-lived objects, but if you’re worried about the performance impact, consider using a builder instead.

Builder

Instead of creating a statement directly, you can pass your Gremlin-groovy string to ScriptGraphStatement.builder, chain method calls to set options, and finally call build():

ScriptGraphStatement statement1 =
    ScriptGraphStatement.builder("system.graph('demo').ifNotExists().create()")
        .withTimeout(Duration.ofSeconds(10))
        .withIdempotence(true)
        .build();

The builder implementation is mutable: every method call returns the same object, only one builder instance will be created no matter how many methods you call on it. As a consequence, the builder object is not thread-safe.

You can also initialize a builder from an existing statement: it will inherit all of its options.

ScriptGraphStatement statement2 =
    ScriptGraphStatement.builder(statement1).withTimeout(Duration.ofSeconds(20)).build();

assert statement2.getScript().equals(statement1.getScript());
assert statement2.getTimeout().equals(Duration.ofSeconds(20)); // overridden by the builder
assert statement2.isIdempotent(); // because statement1 was

Parameters

Gremlin-groovy scripts accept parameters, which are always named. Note that, unlike in CQL, placeholders are not prefixed with “:”.

To manage parameters on an existing statement, use setQueryParam / removeQueryParam:

ScriptGraphStatement statement =
    ScriptGraphStatement.newInstance("g.addV(label, vertexLabel)")
        .setQueryParam("vertexLabel", "test_vertex_2");

On the builder, use withQueryParam / withoutQueryParams:

ScriptGraphStatement statement =
    ScriptGraphStatement.builder("g.addV(label, vertexLabel)")
        .withQueryParam("vertexLabel", "test_vertex_2")
        .build();

Alternatively, withQueryParams takes multiple parameters as a map.

Use cases for the script API

Building requests as Java strings can be unwieldy, especially for long scripts. Besides, the script API is a bit less performant on the server side. Therefore we recommend the Fluent API instead for graph traversals.

Note however that some types of queries can only be performed through the script API:

• system queries (e.g. creating / dropping a graph);
• configuration;
• DSE graph schema queries.