/** Returns the expression to access a table within a schema. */
public static Expression tableExpression(
Schema schema, Type elementType, String tableName, Class clazz) {
final MethodCallExpression expression;
if (Table.class.isAssignableFrom(clazz)) {
expression =
Expressions.call(
schema.getExpression(),
BuiltinMethod.SCHEMA_GET_TABLE.method,
Expressions.constant(tableName));
} else {
expression =
Expressions.call(
BuiltinMethod.SCHEMAS_QUERYABLE.method,
DataContext.ROOT,
schema.getExpression(),
Expressions.constant(elementType),
Expressions.constant(tableName));
}
return Types.castIfNecessary(clazz, expression);
}
/** Returns the expression for a sub-schema. */
public static Expression subSchemaExpression(Schema schema, String name, Class type) {
// (Type) schemaExpression.getSubSchema("name")
Expression call =
Expressions.call(
schema.getExpression(),
BuiltinMethod.SCHEMA_GET_SUB_SCHEMA.method,
Expressions.constant(name));
// CHECKSTYLE: IGNORE 2
//noinspection unchecked
if (false && type != null && !type.isAssignableFrom(Schema.class)) {
return unwrap(call, type);
}
return call;
}
@Override
protected PreparedExecution implement(
RelDataType rowType,
RelNode rootRel,
SqlKind sqlKind,
ClassDeclaration decl,
Argument[] args) {
RelDataType resultType = rootRel.getRowType();
boolean isDml = sqlKind.belongsTo(SqlKind.DML);
javaCompiler = createCompiler();
EnumerableRelImplementor relImplementor =
getRelImplementor(rootRel.getCluster().getRexBuilder());
BlockExpression expr = relImplementor.implementRoot((EnumerableRel) rootRel);
ParameterExpression root0 = Expressions.parameter(DataContext.class, "root0");
String s =
Expressions.toString(
Blocks.create(
Expressions.declare(
Modifier.FINAL, (ParameterExpression) schema.getExpression(), root0),
expr),
false);
final Executable executable;
try {
executable =
(Executable)
ExpressionEvaluator.createFastScriptEvaluator(
s, Executable.class, new String[] {root0.name});
} catch (Exception e) {
throw Helper.INSTANCE.wrap("Error while compiling generated Java code:\n" + s, e);
}
if (timingTracer != null) {
timingTracer.traceTime("end codegen");
}
if (timingTracer != null) {
timingTracer.traceTime("end compilation");
}
return new PreparedExecution(
null, rootRel, resultType, isDml, mapTableModOp(isDml, sqlKind), null) {
public Object execute() {
return executable.execute(schema);
}
};
}
public Expression getExpression(SchemaPlus parentSchema, String name) {
return schema.getExpression(parentSchema, name);
}