Getting value from environment variables for maxBufferingDurationMs. …

…Information about it added to README (#14)

Getting value from environment variables for maxBufferingDurationMs

examples/java/src/main/java/org/apache/beam/examples/complete/datatokenization/README.md

@@ -137,6 +137,9 @@ The template allows for the user to supply the following optional parameter:
 
 - **nonTokenizedDeadLetterPath**: Folder where failed to tokenize data will be stored
 
+The template also allows user to override the environment variable:
+
+- **MAX_BUFFERING_DURATION_MS**: Max duration of buffering rows in milliseconds. Default value: 100ms.
 
 in the following format:
 

examples/java/src/main/java/org/apache/beam/examples/complete/datatokenization/transforms/DataProtectors.java

@@ -77,7 +77,8 @@ public class DataProtectors {
   private static final Logger LOG = LoggerFactory.getLogger(DataProtectors.class);
 
   public static final String ID_FIELD_NAME = "ID";
-  private static final Integer MAX_BUFFERING = 100;
+  private static final Long MAX_BUFFERING_DURATION_MS =
+      Long.valueOf(System.getenv().getOrDefault("MAX_BUFFERING_DURATION_MS", "100"));
 
   /**
    * The {@link RowToTokenizedRow} transform converts {@link Row} to {@link TableRow} objects. The
@@ -107,7 +108,7 @@ public PCollectionTuple expand(PCollection<KV<Integer, Row>> inputRows) {
       FailsafeElementCoder<Row, Row> coder =
           FailsafeElementCoder.of(RowCoder.of(schema()), RowCoder.of(schema()));
 
-      Duration maxBuffering = Duration.millis(MAX_BUFFERING);
+      Duration maxBuffering = Duration.millis(MAX_BUFFERING_DURATION_MS);
       PCollectionTuple pCollectionTuple =
           inputRows
               .apply(