[jira] [Updated] (FLINK-3881) Error in Java 8 Documentation Sample

["Mans Singh (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-3881?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Mans Singh updated FLINK-3881:
------------------------------
    Description: 
The java8 documentation (https://ci.apache.org/projects/flink/flink-docs-master/apis/java8.html) has samples (one of them) included below:

{code:java}
DataSet<String> input = env.fromElements(1, 2, 3);

// collector type must be declared
input.flatMap((Integer number, Collector<String> out) -> {
    for(int i = 0; i < number; i++) {
        out.collect("a");
    }
})
// returns "a", "a", "aa", "a", "aa" , "aaa"
.print();
{code}

I tried the sample and I think there are two issues with it (unless I have missed anything):
1. The DataSet should be DataSet<Integer> and not DataSet<String>
2. There should probably be a StringBuffer that in the flatMap function that is used to  append "a" in the for loop and output (out.collect(buffer.toString()) it rather than just out.collect("a");.  Currently, this produces only "a" each time rather than   "a", "a", "aa", "a", "aa" , "aaa" as shown the comments.

  was:
The java8 documentation (https://ci.apache.org/projects/flink/flink-docs-master/apis/java8.html) has samples (one of them) included below:

DataSet<String> input = env.fromElements(1, 2, 3);

// collector type must be declared
input.flatMap((Integer number, Collector<String> out) -> {
    for(int i = 0; i < number; i++) {
        out.collect("a");
    }
})
// returns "a", "a", "aa", "a", "aa" , "aaa"
.print();

I tried the sample and I think there are two issues with it (unless I have missed anything):
1. The DataSet should be DataSet<Integer> and not DataSet<String>
2. It should have a StringBuffer that appends "a" in the for loop and output (out.collect(buffer.toString()) it rather than just out.collect("a");.  Currently, this produces only "a" each time rather than   "a", "a", "aa", "a", "aa" , "aaa" as shown the comments.


> Error in Java 8 Documentation Sample
> ------------------------------------
>
>                 Key: FLINK-3881
>                 URL: https://issues.apache.org/jira/browse/FLINK-3881
>             Project: Flink
>          Issue Type: Bug
>          Components: Documentation
>    Affects Versions: 1.0.3
>         Environment: All
>            Reporter: Mans Singh
>            Priority: Minor
>              Labels: docuentation, java8, sample
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> The java8 documentation (https://ci.apache.org/projects/flink/flink-docs-master/apis/java8.html) has samples (one of them) included below:
> {code:java}
> DataSet<String> input = env.fromElements(1, 2, 3);
> // collector type must be declared
> input.flatMap((Integer number, Collector<String> out) -> {
>     for(int i = 0; i < number; i++) {
>         out.collect("a");
>     }
> })
> // returns "a", "a", "aa", "a", "aa" , "aaa"
> .print();
> {code}
> I tried the sample and I think there are two issues with it (unless I have missed anything):
> 1. The DataSet should be DataSet<Integer> and not DataSet<String>
> 2. There should probably be a StringBuffer that in the flatMap function that is used to  append "a" in the for loop and output (out.collect(buffer.toString()) it rather than just out.collect("a");.  Currently, this produces only "a" each time rather than   "a", "a", "aa", "a", "aa" , "aaa" as shown the comments.



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