flink-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From fhueske <...@git.apache.org>
Subject [GitHub] flink pull request #3450: [FLINK-5794][doc] update the documentation about ...
Date Wed, 01 Mar 2017 17:57:40 GMT
Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3450#discussion_r103747171
  
    --- Diff: docs/dev/table_api.md ---
    @@ -4819,7 +4826,7 @@ object TimestampModifier extends ScalarFunction {
     
     Similar to a user-defined scalar function, a user-defined table function takes zero,
one, or multiple scalar values as input parameters. However in contrast to a scalar function,
it can return an arbitrary number of rows as output instead of a single value. The returned
rows may consist of one or more columns. 
     
    -In order to define a table function one has to extend the base class `TableFunction`
in `org.apache.flink.table.functions` and implement (one or more) evaluation methods. The
behavior of a table function is determined by its evaluation methods. An evaluation method
must be declared `public` and named `eval`. The `TableFunction` can be overloaded by implementing
multiple methods named `eval`. The parameter types of the evaluation methods determine all
valid parameters of the table function. The type of the returned table is determined by the
generic type of `TableFunction`. Evaluation methods emit output rows using the protected `collect(T)`
method.
    +In order to define a table function one has to extend the base class `TableFunction`
in `org.apache.flink.table.functions` and implement (one or more) evaluation methods. Moreover
constructor of the user-defined table function can contain constructor arguments. The behavior
of a table function is determined by its evaluation methods. An evaluation method must be
declared `public` and named `eval`. The `TableFunction` can be overloaded by implementing
multiple methods named `eval`. The parameter types of the evaluation methods determine all
valid parameters of the table function. The type of the returned table is determined by the
generic type of `TableFunction`. Evaluation methods emit output rows using the protected `collect(T)`
method.
    --- End diff --
    
    I would remove the sentence about the constructor because it breaks the explanation flow.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastructure@apache.org or file a JIRA ticket
with INFRA.
---

Mime
View raw message