sonam-vend commented on a change in pull request #13817:
URL: https://github.com/apache/beam/pull/13817#discussion_r579807894
##########
File path:
sdks/java/extensions/sql/src/main/java/org/apache/beam/sdk/extensions/sql/impl/transform/BeamBuiltinAggregations.java
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@@ -495,4 +504,81 @@ public Long extractOutput(Long accumulator) {
return accumulator;
}
}
+ /**
+ * Logical_And function implementation
+ *
+ * <p>Returns the logical AND of all non-NULL expressions. Returns NULL if
there are zero input
+ * rows or expression evaluates to NULL for all rows.
+ */
+ public static class LogicalAnd extends CombineFn<Boolean, LogicalAnd.Accum,
Boolean> {
+ static class Accum {
+ /** Initially, input is empty. */
+ boolean isEmpty = true;
+ /** true if any null value is seen in the input, null values are to be
ignored. */
+ boolean isNull = false;
+ /** logical_and operation result. */
+ boolean logicalAnd = true;
+ }
+
+ @Override
+ public Accum createAccumulator() {
+ return new Accum();
+ }
+
+ @Override
+ public Accum addInput(Accum accum, Boolean input) {
+ /** when accum is empty and it sees null, it remains null */
+ if (accum.isEmpty && input == null) {
+ accum.isNull = true;
+ return accum;
+ }
+ /** when accum is null and it sees null, it remains null */
+ if (accum.isNull && input == null) {
+ accum.isNull = true;
+ return accum;
+ }
+ /** when accum is neither null and nor empty, it remains unchanged */
+ if (!accum.isNull && !accum.isEmpty && input == null) {
+ return accum;
+ }
+ /** when accum sees non-null value, accum becomes non-empty, non-null */
+ accum.isEmpty = false;
+ accum.isNull = false;
+ accum.logicalAnd = (accum.logicalAnd && input);
+ return accum;
+ }
+
+ @Override
+ public Accum mergeAccumulators(Iterable<Accum> accums) {
+ LogicalAnd.Accum merged = createAccumulator();
+
+ /** merged accum has isNull=true when all accums have isNull=true */
+ if (StreamSupport.stream(accums.spliterator(), false).allMatch(a ->
a.isNull)) {
Review comment:
@ibzib Thanks for this wonderful neat code.
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