danny0405 commented on a change in pull request #1449: [CALCITE-3302] Implement
CLASSIFIER and LAST function for MATCH_RECOG…
URL: https://github.com/apache/calcite/pull/1449#discussion_r323083873
##########
File path:
core/src/main/java/org/apache/calcite/adapter/enumerable/RexImpTable.java
##########
@@ -2925,6 +2934,83 @@ private Expression normalize(SqlTypeName typeName,
Expression e) {
}
}
}
+
+ /** Implements CLASSIFIER MR Function */
+ private static class ClassifierImplementor implements MatchImplementor {
+ @Override public Expression implement(RexToLixTranslator translator,
RexCall call,
+ ParameterExpression row,
ParameterExpression rows,
+ ParameterExpression symbols,
ParameterExpression i) {
+ return Types.castIfNecessary(String.class,
+ Expressions.call(
+ symbols,
+ Types.lookupMethod(List.class, "get", int.class), i));
+ }
+ }
+
+ /** Implements LAST MR Function */
+ private static class LastImplementor implements MatchImplementor {
+ @Override public Expression implement(RexToLixTranslator translator,
RexCall call,
+ ParameterExpression row,
ParameterExpression rows,
+ ParameterExpression symbols,
ParameterExpression i) {
+ final RexNode node = call.getOperands().get(0);
+
+ final String alpha = ((RexPatternFieldRef)
call.getOperands().get(0)).getAlpha();
+
+ final BinaryExpression lastIndex = Expressions.subtract(
+ Expressions.call(rows, Types.lookupMethod(List.class, "size")),
+ Expressions.constant(1)
+ );
+
+ // Just take the last one, if exists
+ if ("*".equals(alpha)) {
+ ((EnumerableMatch.PassedRowsInputGetter)
translator.inputGetter).setIndex(i);
+ // Important, unbox the node / expression to avoid NullAs.NOT_POSSIBLE
+ final RexPatternFieldRef ref = (RexPatternFieldRef) node;
+ final RexPatternFieldRef newRef = new RexPatternFieldRef(
+ ref.getAlpha(),
+ ref.getIndex(),
+ translator.typeFactory.createTypeWithNullability(ref.getType(),
true)
+ );
+ final Expression expression = translator.translate(newRef,
NullAs.NULL);
+ ((EnumerableMatch.PassedRowsInputGetter)
translator.inputGetter).setIndex(null);
+ return expression;
+ } else {
+ // Alpha != "*" so we have to search for a specific one to find and
use that, if found
+ ((EnumerableMatch.PassedRowsInputGetter)
translator.inputGetter).setIndex(
+ Expressions.call(
+ Types.lookupMethod(MatchUtils.class, "lastWithSymbol",
String.class,
+ List.class, List.class, int.class),
+ Expressions.constant(alpha),
+ rows,
+ symbols,
+ i));
+
+ // Important, unbox the node / expression to avoid NullAs.NOT_POSSIBLE
+ final RexPatternFieldRef ref = (RexPatternFieldRef) node;
+ final RexPatternFieldRef newRef = new RexPatternFieldRef(
+ ref.getAlpha(),
+ ref.getIndex(),
+ translator.typeFactory.createTypeWithNullability(ref.getType(),
true)
+ );
+ final Expression expression = translator.translate(newRef,
NullAs.NULL);
+ ((EnumerableMatch.PassedRowsInputGetter)
translator.inputGetter).setIndex(null);
+ return expression;
+ }
+ }
+ }
+
+ /** Implements PREV MR Function */
+ private static class PrevImplementor implements CallImplementor {
+ @Override public Expression implement(RexToLixTranslator translator,
RexCall call,
+ NullAs nullAs) {
Review comment:
Fix the indent.
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