[jira] [Commented] (FLINK-3097) Add support for custom functions in Table API

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-3097?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15382483#comment-15382483 ] 

ASF GitHub Bot commented on FLINK-3097:
---------------------------------------

GitHub user twalthr opened a pull request:

    https://github.com/apache/flink/pull/2265

    [FLINK-3097] [table] Add support for custom functions in Table API

    Thanks for contributing to Apache Flink. Before you open your pull request, please take the following check list into consideration.
    If your changes take all of the items into account, feel free to open your pull request. For more information and/or questions please refer to the [How To Contribute guide](http://flink.apache.org/how-to-contribute.html).
    In addition to going through the list, please provide a meaningful description of your changes.
    
    - [x] General
      - The pull request references the related JIRA issue ("[FLINK-XXX] Jira title text")
      - The pull request addresses only one issue
      - Each commit in the PR has a meaningful commit message (including the JIRA id)
    
    - [ ] Documentation
      - Documentation has been added for new functionality
      - Old documentation affected by the pull request has been updated
      - JavaDoc for public methods has been added
    
    - [x] Tests & Build
      - Functionality added by the pull request is covered by tests
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    This PR introduces user-defined scalar functions for the Table and SQL API.
    I will add documentation soon, but this is the general syntax so far:
    
    In Java:
    ```java
    public class HashCode extends ScalarFunction {
    	public int eval(String s) {
    		return s.hashCode();
    	}
    }
    
    tableEnv.registerFunction("hashCode", new HashCode());
    Table result = table.select("text.hashCode()");
    Table result = tableEnv.sql("SELECT hashCode(text) FROM MyTable")
    ```
    
    In Scala:
    ```scala
    object hashCode extends ScalarFunction {
      def eval(s: String): Int = {
        s.hashCode()
      }
    }
    
    val result = table.select(hashCode(text));
    val result = tableEnv.sql("SELECT hashCode(text) FROM MyTable")
    ```
    


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/twalthr/flink FLINK-3097

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/flink/pull/2265.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #2265
    
----
commit 3b792569bccea843646d8c88592e9c20ecf0ed37
Author: twalthr <tw...@apache.org>
Date:   2016-07-12T10:22:41Z

    [FLINK-3097] [table] Add support for custom functions in Table API

----


> Add support for custom functions in Table API
> ---------------------------------------------
>
>                 Key: FLINK-3097
>                 URL: https://issues.apache.org/jira/browse/FLINK-3097
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>            Reporter: Timo Walther
>            Assignee: Timo Walther
>
> Currently, the Table API has a very limited set of built-in functions. Support for custom functions can solve this problem. Adding of a custom row function could look like:
> {code}
> TableEnvironment tableEnv = new TableEnvironment();
> RowFunction<String> rf = new RowFunction<String>() {
>     @Override
>     public String call(Object[] args) {
>         return ((String) args[0]).trim();
>     }
> };
> tableEnv.getConfig().registerRowFunction("TRIM", rf,
>     BasicTypeInfo.STRING_TYPE_INFO);
> DataSource<Tuple1<String>> input = env.fromElements(
>     new Tuple1<>(" 1 "));
> Table table = tableEnv.fromDataSet(input);
> Table result = table.select("TRIM(f0)");
> {code}
> This feature is also necessary as part of FLINK-2099.



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