mspruc commented on code in PR #692:
URL: https://github.com/apache/wayang/pull/692#discussion_r2820788957
##########
wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/sources/fs/JavaCSVTableSource.java:
##########
@@ -163,19 +168,58 @@ public List<ChannelDescriptor>
getSupportedOutputChannels(final int index) {
* @param path of the file
* @return the {@link Stream}
*/
- private static Stream<String> streamLines(final String path) {
+ private Stream<String> streamLines(final String path) {
Review Comment:
Keep this static
##########
wayang-api/wayang-api-sql/src/main/java/org/apache/wayang/api/sql/sources/fs/JavaCSVTableSource.java:
##########
@@ -163,19 +168,58 @@ public List<ChannelDescriptor>
getSupportedOutputChannels(final int index) {
* @param path of the file
* @return the {@link Stream}
*/
- private static Stream<String> streamLines(final String path) {
+ private Stream<String> streamLines(final String path) {
final FileSystem fileSystem =
FileSystems.getFileSystem(path).orElseThrow(
() -> new IllegalStateException(String.format("No file system
found for %s", path)));
try {
final Iterator<String> lineIterator =
createLineIterator(fileSystem, path);
- lineIterator.next(); // skip header row
+
+ if (!lineIterator.hasNext()) {
+ throw new IllegalStateException(String.format(
+ "CSV file '%s' is empty. Expected a header row (e.g.,
'id:int,name:string').",
+ path));
+ }
+
+ final String headerLine = lineIterator.next(); // read & skip
header
+ validateHeaderLine(headerLine);
return
StreamSupport.stream(Spliterators.spliteratorUnknownSize(lineIterator, 0),
false);
} catch (final IOException e) {
throw new WayangException(String.format("%s failed to read %s.",
FileUtils.class, path), e);
}
}
+ /**
+ * Validates the CSV header for Calcite compatibility.
+ * Checks that the header is present, uses comma separators (not the data
+ * delimiter), and each column follows the 'name:type' format
+ * (e.g., 'id:int,name:string,email:string'). Note that Calcite hardcodes
+ * commas for header parsing, while data rows use Wayang's configurable
+ * separator (default ';').
+ *
+ * @param path the filesystem path to the CSV file
+ */
+ private void validateHeaderLine(final String headerLine) {
Review Comment:
Make this static
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