[GitHub] [calcite] asereda-gs commented on issue #1032: [CALCITE-2769] CSV Adapter does not handle - Empty and malformed csv lines, space before or after comma

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asereda-gs commented on issue #1032: [CALCITE-2769] CSV Adapter does not handle - Empty and malformed csv lines, space before or after comma
URL: https://github.com/apache/calcite/pull/1032#issuecomment-471768930
 
 
   Proposed solution looks very specific. 
   
   What people think about the following alternative: 
   
   1. Add default method to [Source](https://github.com/apache/calcite/blob/9721283bd0ce46a337f51a3691585cca8003e399/core/src/main/java/org/apache/calcite/util/Source.java) interface:
   
   ```java
     default Stream<String> lines() {
        // TODO add close() logic
        return new BufferedReader(reader()).lines();
      }
   ```
   
   2. Add / Replace constructor of [CsvSchema](https://github.com/apache/calcite/blob/master/example/csv/src/main/java/org/apache/calcite/adapter/csv/CsvSchema.java) to accept a list (stream) of sources (instead of parent dir as File) : 
   ```java
   public CsvSchema(Stream<Source> sources, CsvTable.Flavor flavor) {
   }
   ```
   
   If user wants to modify / filter lines based on particular logic they can wrap existing source and override `lines()` method:
   ```java
   return lines().map(String::trim()).filter(line -> !line.isEmpty());
   ````
   It also has the advantage of accepting generic sources of data like HDFS.
   

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