From 6217c670271843d3010c317da8902cd2504464fb Mon Sep 17 00:00:00 2001 From: nishantmonu51 Date: Tue, 15 Apr 2014 22:55:40 +0530 Subject: [PATCH] complete javadoc, add comment, use Lists.reverse --- .../io/druid/query/aggregation/AggregatorUtil.java | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/processing/src/main/java/io/druid/query/aggregation/AggregatorUtil.java b/processing/src/main/java/io/druid/query/aggregation/AggregatorUtil.java index 6c4b49fd067..e0e3fc2d1ed 100644 --- a/processing/src/main/java/io/druid/query/aggregation/AggregatorUtil.java +++ b/processing/src/main/java/io/druid/query/aggregation/AggregatorUtil.java @@ -28,8 +28,11 @@ import java.util.Set; public class AggregatorUtil { - /** returns the list of dependent postAggregators that should be calculated in order to calculate given postAgg - * @param postAggregatorList List of postAggregator, there is a restriction that the postAgg should be in order that it can + /** + * returns the list of dependent postAggregators that should be calculated in order to calculate given postAgg + * + * @param postAggregatorList List of postAggregator, there is a restriction that the list should be in an order + * such that all the dependencies of any given aggregator should occur before that aggregator * @param postAggName name of the postAgg on which dependency is to be calculated */ public static List pruneDependentPostAgg(List postAggregatorList, String postAggName) @@ -37,9 +40,8 @@ public class AggregatorUtil LinkedList rv = Lists.newLinkedList(); Set deps = new HashSet<>(); deps.add(postAggName); - // Iterate backwards to calculate deps - for (int i = postAggregatorList.size() - 1; i >= 0; i--) { - PostAggregator agg = postAggregatorList.get(i); + // Iterate backwards to find the last calculated aggregate and add dependent aggregator as we find dependencies in reverse order + for (PostAggregator agg : Lists.reverse(postAggregatorList)) { if (deps.contains(agg.getName())) { rv.addFirst(agg); // add to the beginning of List deps.remove(agg.getName());