sorry for late reply cuz I'm on my vocation until next Monday，then I'll read all you comments carefully，really appreciate your work， thanks.
On Thu, May 23, 2019, 04:27 Julian Hyde (JIRA) <[email protected]> wrote: > > [ > https://issues.apache.org/jira/browse/CALCITE-3065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16846211#comment-16846211 > ] > > Julian Hyde commented on CALCITE-3065: > -------------------------------------- > > The basic idea is that you call {{getLiteralAs}} with a class {{c}}, then > the value that comes back is an instance of {{c}}. This is a nice simple > contract. > > If {{c}} is {{int.class}}, then it is impossible to fulfill that contract. > A {{java.lang.Integer}} is not an instance of {{int.class}}. (No java > object is an instance of {{int.class}}.) > > (Scala's type system may deceive you about that. But this is a Java API.) > > As I said already, you can fix this by adding one line of code to your > program. That is better, in my opinion, than making the contract more > complicated. > > Regarding decimals. You are correct that Calcite internally stores all > numeric literals using {{BigDecimal}}. This is because {{BigDecimal}} can > represent every possible numeric literal value, and can do so without > losing precision. (If you store say 0.1 as a double, it will get rounded.) > If you want to consume the value as a {{java.math.BigDecimal}}, or as a > {{java.lang.Number}}, or as an {{java.lang.Integer}}, or as a > {{java.lang.Float}}, you can do that, and the API will convert the value to > the type that you choose. But you cannot ask for {{int}}, because we cannot > give you an {{int}}. > > > RexLiteral#getValueAs should consider primitive type > > ---------------------------------------------------- > > > > Key: CALCITE-3065 > > URL: https://issues.apache.org/jira/browse/CALCITE-3065 > > Project: Calcite > > Issue Type: Improvement > > Components: core > > Reporter: Jiatao Tao > > Priority: Major > > Labels: pull-request-available > > Attachments: image-2019-05-13-12-04-36-365.png, > image-2019-05-17-08-23-52-735.png > > > > Time Spent: 40m > > Remaining Estimate: 0h > > > > !image-2019-05-13-12-04-36-365.png! > > > > -- > This message was sent by Atlassian JIRA > (v7.6.3#76005) >
