private Expression translate0(RexNode expr) {
if (expr instanceof RexInputRef) {
// TODO: multiple inputs, e.g. joins
final Expression input = getInput(0);
final int index = ((RexInputRef) expr).getIndex();
final List<RelDataTypeField> fields = program.getInputRowType().getFieldList();
final RelDataTypeField field = fields.get(index);
if (fields.size() == 1) {
return input;
} else if (input.getType() == Object[].class) {
return Expressions.convert_(
Expressions.arrayIndex(input, Expressions.constant(field.getIndex())),
Types.box(JavaRules.EnumUtil.javaClass(typeFactory, field.getType())));
} else {
return Expressions.field(input, field.getName());
}
}
if (expr instanceof RexLocalRef) {
return translate(program.getExprList().get(((RexLocalRef) expr).getIndex()));
}
if (expr instanceof RexLiteral) {
return Expressions.constant(
((RexLiteral) expr).getValue(), typeFactory.getJavaClass(expr.getType()));
}
if (expr instanceof RexCall) {
final RexCall call = (RexCall) expr;
final SqlOperator operator = call.getOperator();
final ExpressionType expressionType = SQL_TO_LINQ_OPERATOR_MAP.get(operator);
if (expressionType != null) {
switch (operator.getSyntax()) {
case Binary:
return Expressions.makeBinary(
expressionType, translate(call.getOperands()[0]), translate(call.getOperands()[1]));
case Postfix:
case Prefix:
return Expressions.makeUnary(expressionType, translate(call.getOperands()[0]));
default:
throw new RuntimeException("unknown syntax " + operator.getSyntax());
}
}
Method method = SQL_OP_TO_JAVA_METHOD_MAP.get(operator);
if (method != null) {
List<Expression> exprs = translateList(Arrays.asList(call.operands));
return !Modifier.isStatic(method.getModifiers())
? Expressions.call(exprs.get(0), method, exprs.subList(1, exprs.size()))
: Expressions.call(method, exprs);
}
switch (expr.getKind()) {
default:
throw new RuntimeException("cannot translate expression " + expr);
}
}
throw new RuntimeException("cannot translate expression " + expr);
}
/** 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);
}
public void testWriteAnonymousClass() {
// final List<String> baz = Arrays.asList("foo", "bar");
// new AbstractList<String>() {
// public int size() {
// return baz.size();
// }
// public String get(int index) {
// return ((String) baz.get(index)).toUpperCase();
// }
// }
final ParameterExpression bazParameter =
Expressions.parameter(Types.of(List.class, String.class), "baz");
final ParameterExpression indexParameter = Expressions.parameter(Integer.TYPE, "index");
BlockExpression e =
Expressions.block(
Expressions.declare(
Modifier.FINAL,
bazParameter,
Expressions.call(
Arrays.class,
"asList",
Arrays.<Expression>asList(
Expressions.constant("foo"), Expressions.constant("bar")))),
Expressions.statement(
Expressions.new_(
Types.of(AbstractList.class, String.class),
Collections.<Expression>emptyList(),
Arrays.<MemberDeclaration>asList(
Expressions.fieldDecl(
Modifier.PUBLIC | Modifier.FINAL,
Expressions.parameter(String.class, "qux"),
Expressions.constant("xyzzy")),
Expressions.methodDecl(
Modifier.PUBLIC,
Integer.TYPE,
"size",
Collections.<ParameterExpression>emptyList(),
Blocks.toFunctionBlock(
Expressions.call(
bazParameter, "size", Collections.<Expression>emptyList()))),
Expressions.methodDecl(
Modifier.PUBLIC,
String.class,
"get",
Arrays.asList(indexParameter),
Blocks.toFunctionBlock(
Expressions.call(
Expressions.convert_(
Expressions.call(
bazParameter,
"get",
Arrays.<Expression>asList(indexParameter)),
String.class),
"toUpperCase",
Collections.<Expression>emptyList())))))));
assertEquals(
"{\n"
+ " final java.util.List<String> baz = java.util.Arrays.asList(\"foo\", \"bar\");\n"
+ " new java.util.AbstractList<String>(){\n"
+ " public final String qux = \"xyzzy\";\n"
+ " public int size() {\n"
+ " return baz.size();\n"
+ " }\n"
+ "\n"
+ " public String get(int index) {\n"
+ " return ((String) baz.get(index)).toUpperCase();\n"
+ " }\n"
+ "\n"
+ " };\n"
+ "}\n",
Expressions.toString(e));
}
