public RexNode toRex(Expression expression) {
switch (expression.getNodeType()) {
case MemberAccess:
return rexBuilder.makeFieldAccess(
toRex(((MemberExpression) expression).expression),
((MemberExpression) expression).field.getName());
case GreaterThan:
return binary(expression, SqlStdOperatorTable.greaterThanOperator);
case LessThan:
return binary(expression, SqlStdOperatorTable.lessThanOperator);
case Parameter:
return parameter((ParameterExpression) expression);
case Call:
MethodCallExpression call = (MethodCallExpression) expression;
SqlOperator operator = RexToLixTranslator.JAVA_TO_SQL_METHOD_MAP.get(call.method);
if (operator != null) {
return rexBuilder.makeCall(
operator,
toRex(
Expressions.<Expression>list()
.appendIfNotNull(call.targetExpression)
.appendAll(call.expressions)));
}
throw new RuntimeException("Could translate call to method " + call.method);
case Constant:
final ConstantExpression constant = (ConstantExpression) expression;
Object value = constant.value;
if (value instanceof Number) {
Number number = (Number) value;
if (value instanceof Double || value instanceof Float) {
return rexBuilder.makeApproxLiteral(BigDecimal.valueOf(number.doubleValue()));
} else if (value instanceof BigDecimal) {
return rexBuilder.makeExactLiteral((BigDecimal) value);
} else {
return rexBuilder.makeExactLiteral(BigDecimal.valueOf(number.longValue()));
}
} else if (value instanceof Boolean) {
return rexBuilder.makeLiteral((Boolean) value);
} else {
return rexBuilder.makeLiteral(constant.toString());
}
default:
throw new UnsupportedOperationException(
"unknown expression type " + expression.getNodeType() + " " + expression);
}
}
