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);
}
public void testWrite() {
assertEquals(
"1 + 2.0F + 3L + Long.valueOf(4L)",
Expressions.toString(
Expressions.add(
Expressions.add(
Expressions.add(Expressions.constant(1), Expressions.constant(2F, Float.TYPE)),
Expressions.constant(3L, Long.TYPE)),
Expressions.constant(4L, Long.class))));
assertEquals(
"new java.math.BigDecimal(31415926L, 7)",
Expressions.toString(Expressions.constant(BigDecimal.valueOf(314159260, 8))));
// Parentheses needed, to override the left-associativity of +.
assertEquals(
"1 + (2 + 3)",
Expressions.toString(
Expressions.add(
Expressions.constant(1),
Expressions.add(Expressions.constant(2), Expressions.constant(3)))));
// No parentheses needed; higher precedence of * achieves the desired
// effect.
assertEquals(
"1 + 2 * 3",
Expressions.toString(
Expressions.add(
Expressions.constant(1),
Expressions.multiply(Expressions.constant(2), Expressions.constant(3)))));
assertEquals(
"1 * (2 + 3)",
Expressions.toString(
Expressions.multiply(
Expressions.constant(1),
Expressions.add(Expressions.constant(2), Expressions.constant(3)))));
// Parentheses needed, to overcome right-associativity of =.
assertEquals(
"(1 = 2) = 3",
Expressions.toString(
Expressions.assign(
Expressions.assign(Expressions.constant(1), Expressions.constant(2)),
Expressions.constant(3))));
// Ternary operator.
assertEquals(
"1 < 2 ? (3 < 4 ? 5 : 6) : 7 < 8 ? 9 : 10",
Expressions.toString(
Expressions.condition(
Expressions.lessThan(Expressions.constant(1), Expressions.constant(2)),
Expressions.condition(
Expressions.lessThan(Expressions.constant(3), Expressions.constant(4)),
Expressions.constant(5),
Expressions.constant(6)),
Expressions.condition(
Expressions.lessThan(Expressions.constant(7), Expressions.constant(8)),
Expressions.constant(9),
Expressions.constant(10)))));
assertEquals(
"0 + (double) (2 + 3)",
Expressions.toString(
Expressions.add(
Expressions.constant(0),
Expressions.convert_(
Expressions.add(Expressions.constant(2), Expressions.constant(3)),
Double.TYPE))));
assertEquals(
"a.empno",
Expressions.toString(
Expressions.field(Expressions.parameter(Linq4jTest.Employee.class, "a"), "empno")));
assertEquals(
"java.util.Collections.EMPTY_LIST",
Expressions.toString(Expressions.field(null, Collections.class, "EMPTY_LIST")));
final ParameterExpression paramX = Expressions.parameter(String.class, "x");
assertEquals(
"new net.hydromatic.linq4j.function.Function1() {\n"
+ " public int apply(String x) {\n"
+ " return x.length();\n"
+ " }\n"
+ " public Object apply(Object x) {\n"
+ " return apply(\n"
+ " (String) x);\n"
+ " }\n"
+ "}\n",
Expressions.toString(
Expressions.lambda(
Function1.class,
Expressions.call(paramX, "length", Collections.<Expression>emptyList()),
Arrays.asList(paramX))));
assertEquals(
"new String[] {\n" + " \"foo\",\n" + " null,\n" + " \"bar\\\"baz\"}",
Expressions.toString(
Expressions.newArrayInit(
String.class,
Arrays.<Expression>asList(
Expressions.constant("foo"),
Expressions.constant(null),
Expressions.constant("bar\"baz")))));
assertEquals(
"(int) ((String) (Object) \"foo\").length()",
Expressions.toString(
Expressions.convert_(
Expressions.call(
Expressions.convert_(
Expressions.convert_(Expressions.constant("foo"), Object.class),
String.class),
"length",
Collections.<Expression>emptyList()),
Integer.TYPE)));
// resolving a static method
assertEquals(
"Integer.valueOf(\"0123\")",
Expressions.toString(
Expressions.call(
Integer.class,
"valueOf",
Collections.<Expression>singletonList(Expressions.constant("0123")))));
// precedence of not and instanceof
assertEquals(
"!(o instanceof String)",
Expressions.toString(
Expressions.not(
Expressions.typeIs(Expressions.parameter(Object.class, "o"), String.class))));
// not not
assertEquals(
"!!(o instanceof String)",
Expressions.toString(
Expressions.not(
Expressions.not(
Expressions.typeIs(Expressions.parameter(Object.class, "o"), String.class)))));
}