[GitHub] flink pull request: [FLINK-2021] Rework examples to use ParameterT...

[fhueske]

Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/1581#discussion_r52495987
  
    --- Diff: 
flink-examples/flink-examples-batch/src/main/java/org/apache/flink/examples/java/clustering/KMeans.java
 ---
    @@ -61,42 +62,46 @@
      * <li>Cluster centers are represented by an integer id and a point 
value.<br>
      * For example <code>"1 6.2 3.2\n2 2.9 5.7\n"</code> gives two centers 
(id=1, x=6.2, y=3.2) and (id=2, x=2.9, y=5.7).
      * </ul>
    - * 
    + *
      * <p>
    - * Usage: <code>KMeans &lt;points path&gt; &lt;centers path&gt; &lt;result 
path&gt; &lt;num iterations&gt;</code><br>
    - * If no parameters are provided, the program is run with default data 
from {@link org.apache.flink.examples.java.clustering.util.KMeansData} and 10 
iterations. 
    - * 
    + * Usage: <code>KMeans --points &lt;path&gt; --centroids &lt;path&gt; 
--output &lt;path&gt; --iterations &lt;n&gt;</code><br>
    + * If no parameters are provided, the program is run with default data 
from {@link org.apache.flink.examples.java.clustering.util.KMeansData} and 10 
iterations.
    + *
      * <p>
      * This example shows how to use:
      * <ul>
      * <li>Bulk iterations
      * <li>Broadcast variables in bulk iterations
    - * <li>Custom Java objects (PoJos)
    + * <li>Custom Java objects (POJOs)
      * </ul>
      */
     @SuppressWarnings("serial")
     public class KMeans {
    -   
    -   // 
*************************************************************************
    -   //     PROGRAM
    -   // 
*************************************************************************
    -   
    +
        public static void main(String[] args) throws Exception {
    -           
    -           if(!parseParameters(args)) {
    -                   return;
    +
    +           // Checking input parameters
    +           final ParameterTool params = ParameterTool.fromArgs(args);
    +           if (params.getNumberOfParameters() < 4) {
    --- End diff --
    
    We used this pattern to check unnamed parameters. I think we can do better 
now and a shorter message into the `else` clause of the named parameter check. 
    For this example print something like "Executing K-Means example with 
default point data set. Use --points to specify file input." in the `else` case 
of the `getPointDataSet()` method.


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