Developer guide

Import the Trevas engine

<dependency>
    <groupId>fr.insee.trevas</groupId>
    <artifactId>vtl-engine</artifactId>
    <version>1.7.0</version>
</dependency>

Instantiate the Trevas engine

// Start engine
ScriptEngine engine = new ScriptEngineManager().getEngineByName("vtl");

// Add input bindings to engine
Bindings bindings = new SimpleBindings();
InMemoryDataset dataset = new InMemoryDataset(
                List.of(
                        Map.of("var1", "x", "var2", "y", "var3", 5),
                        Map.of("var1", "xx", "var2", "yy", "var3", 10)
                ),
                Map.of("var1", String.class, "var2", String.class, "var3", Long.class),
                Map.of("var1", Role.IDENTIFIER, "var2", Role.ATTRIBUTE, "var3", Role.MEASURE)
);
bindings.put("a", 1);
bindings.put("ds", dataset);
engine.setBindings(b, ScriptContext.ENGINE_SCOPE);

// Execute script
try {
        engine.eval("b := a + 1; " +
					"ds1 := ds;" +
					"ds2 <- ds;");
} catch (VtlScriptException e) {
		logger.warn("Eval failed: ", e);
}

// Get result
Long result = (Long) engine.getBindings(ScriptContext.ENGINE_SCOPE).get("b");
Dataset ds1 = (Dataset) engine.getBindings(ScriptContext.ENGINE_SCOPE).get("ds1");
PersistentDataset result = (PersistentDataset) engine.getBindings(ScriptContext.ENGINE_SCOPE).get("ds2");

Execution mode

Basic mode

Spark mode

Provenance

Provenance