private void analyzeCall(RexCall call, Constancy callConstancy) {
      parentCallTypeStack.add(call.getOperator());

      // visit operands, pushing their states onto stack
      super.visitCall(call);

      // look for NON_CONSTANT operands
      int nOperands = call.getOperands().length;
      List<Constancy> operandStack = stack.subList(stack.size() - nOperands, stack.size());
      for (Constancy operandConstancy : operandStack) {
        if (operandConstancy == Constancy.NON_CONSTANT) {
          callConstancy = Constancy.NON_CONSTANT;
        }
      }

      // Even if all operands are constant, the call itself may
      // be non-deterministic.
      if (!call.getOperator().isDeterministic()) {
        callConstancy = Constancy.NON_CONSTANT;
      } else if (call.getOperator().isDynamicFunction()) {
        // We can reduce the call to a constant, but we can't
        // cache the plan if the function is dynamic
        preparingStmt.disableStatementCaching();
      }

      // Row operator itself can't be reduced to a literal, but if
      // the operands are constants, we still want to reduce those
      if ((callConstancy == Constancy.REDUCIBLE_CONSTANT)
          && (call.getOperator() instanceof SqlRowOperator)) {
        callConstancy = Constancy.NON_CONSTANT;
      }

      if (callConstancy == Constancy.NON_CONSTANT) {
        // any REDUCIBLE_CONSTANT children are now known to be maximal
        // reducible subtrees, so they can be added to the result
        // list
        for (int iOperand = 0; iOperand < nOperands; ++iOperand) {
          Constancy constancy = operandStack.get(iOperand);
          if (constancy == Constancy.REDUCIBLE_CONSTANT) {
            addResult(call.getOperands()[iOperand]);
          }
        }

        // if this cast expression can't be reduced to a literal,
        // then see if we can remove the cast
        if (call.getOperator() == SqlStdOperatorTable.castFunc) {
          reduceCasts(call);
        }
      }

      // pop operands off of the stack
      operandStack.clear();

      // pop this parent call operator off the stack
      parentCallTypeStack.remove(parentCallTypeStack.size() - 1);

      // push constancy result for this call onto stack
      stack.add(callConstancy);
    }
Ejemplo n.º 2
0
  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);
  }