[jira] [Commented] (FLINK-2017) Add predefined required parameters to ParameterTool

[ASF GitHub Bot (JIRA)]

    [ 
https://issues.apache.org/jira/browse/FLINK-2017?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15021030#comment-15021030
 ] 

ASF GitHub Bot commented on FLINK-2017:
---------------------------------------

Github user rmetzger commented on the pull request:

    https://github.com/apache/flink/pull/1097#issuecomment-158765143
  
    I've tested the PR again. 
    I found a minor issue with the alternative arguments.
    input: `--input abc --p 12`,
    code:
    ```java
    RequiredParameters rq = new RequiredParameters();
                rq.add("input");
                rq.add(new 
Option("parallelism").alt("p").defaultValue("1").type(OptionType.INTEGER));
                ParameterTool pt = ParameterTool.fromArgs(args);
                rq.applyTo(pt);
    
                String in = pt.get("input");
                System.out.println("In = "+in + " parallelism = 
"+pt.getInt("parallelism") + " p="+pt.getInt("p"));
    
                System.exit(0);
    ```
    
    error 
    ```
    Exception in thread "main" java.lang.RuntimeException: No data for required 
key 'p'
        at 
org.apache.flink.api.java.utils.ParameterTool.getRequired(ParameterTool.java:236)
        at 
org.apache.flink.api.java.utils.ParameterTool.getInt(ParameterTool.java:272)
        at 
org.apache.flink.examples.java.wordcount.WordCount.main(WordCount.java:69)
    ```
    
    I think we need to set the (default) value for the long and the short 
variant.


> Add predefined required parameters to ParameterTool
> ---------------------------------------------------
>
>                 Key: FLINK-2017
>                 URL: https://issues.apache.org/jira/browse/FLINK-2017
>             Project: Flink
>          Issue Type: Improvement
>    Affects Versions: 0.9
>            Reporter: Robert Metzger
>              Labels: starter
>
> In FLINK-1525 we've added the {{ParameterTool}}.
> During the PR review, there was a request for required parameters.
> This issue is about implementing a facility to define required parameters. 
> The tool should also be able to print a help menu with a list of all 
> parameters.
> This test case shows my initial ideas how to design the API
> {code}
>       @Test
>       public void requiredParameters() {
>               RequiredParameters required = new RequiredParameters();
>               Option input = required.add("input").alt("i").help("Path to 
> input file or directory"); // parameter with long and short variant
>               required.add("output"); // parameter only with long variant
>               Option parallelism = 
> required.add("parallelism").alt("p").type(Integer.class); // parameter with 
> type
>               Option spOption = 
> required.add("sourceParallelism").alt("sp").defaultValue(12).help("Number 
> specifying the number of parallel data source instances"); // parameter with 
> default value, specifying the type.
>               Option executionType = 
> required.add("executionType").alt("et").defaultValue("pipelined").choices("pipelined",
>  "batch");
>               ParameterUtil parameter = ParameterUtil.fromArgs(new 
> String[]{"-i", "someinput", "--output", "someout", "-p", "15"});
>               required.check(parameter);
>               required.printHelp();
>               required.checkAndPopulate(parameter);
>               String inputString = input.get();
>               int par = parallelism.getInteger();
>               String output = parameter.get("output");
>               int sourcePar = parameter.getInteger(spOption.getName());
>       }
> {code}



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