From d5d0012b4f65df1dca3ac8136f95d19e1a9a0437 Mon Sep 17 00:00:00 2001
From: James Duong <james.duong@improving.com>
Date: Mon, 21 Oct 2024 11:07:10 -0700
Subject: [PATCH] Use List#get(0) instead of getFirst() to support older
 compilers

Signed-off-by: James Duong <james.duong@improving.com>
---
 core/src/main/java/org/opensearch/sql/executor/Explain.java  | 2 +-
 .../opensearch/sql/planner/physical/TrendlineOperator.java   | 5 ++---
 .../org/opensearch/sql/ppl/utils/PPLQueryDataAnonymizer.java | 2 +-
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/core/src/main/java/org/opensearch/sql/executor/Explain.java b/core/src/main/java/org/opensearch/sql/executor/Explain.java
index 99d66f1bfc..baedea0fa4 100644
--- a/core/src/main/java/org/opensearch/sql/executor/Explain.java
+++ b/core/src/main/java/org/opensearch/sql/executor/Explain.java
@@ -265,7 +265,7 @@ private List<Map<String, String>> describeTrendlineComputations(
                 ImmutableMap.of(
                     "computationType", computation.getComputationType().name().toLowerCase(Locale.ROOT),
                     "numberOfDataPoints", computation.getNumberOfDataPoints().toString(),
-                    "dataField", computation.getDataField().getChild().getFirst().toString(),
+                    "dataField", computation.getDataField().getChild().get(0).toString(),
                     "alias", computation.getAlias() != null ? computation.getAlias() : ""))
         .collect(Collectors.toList());
   }
diff --git a/core/src/main/java/org/opensearch/sql/planner/physical/TrendlineOperator.java b/core/src/main/java/org/opensearch/sql/planner/physical/TrendlineOperator.java
index c62fbc3300..8a0bfa87c9 100644
--- a/core/src/main/java/org/opensearch/sql/planner/physical/TrendlineOperator.java
+++ b/core/src/main/java/org/opensearch/sql/planner/physical/TrendlineOperator.java
@@ -32,7 +32,6 @@ public class TrendlineOperator extends PhysicalPlan {
   @Getter private final List<Trendline.TrendlineComputation> computations;
   private final List<TrendlineAccumulator> accumulators;
   private final Map<String, Integer> fieldToIndexMap;
-  private boolean hasAnotherRow = false;
 
   public TrendlineOperator(PhysicalPlan input, List<Trendline.TrendlineComputation> computations) {
     this.input = input;
@@ -41,7 +40,7 @@ public TrendlineOperator(PhysicalPlan input, List<Trendline.TrendlineComputation
     fieldToIndexMap = new HashMap<>(computations.size());
     for (int i = 0; i < computations.size(); ++i) {
 
-      fieldToIndexMap.put(computations.get(i).getDataField().getChild().getFirst().toString(), i);
+      fieldToIndexMap.put(computations.get(i).getDataField().getChild().get(0).toString(), i);
     }
   }
 
@@ -76,7 +75,7 @@ public ExprValue next() {
       if (null != computations.get(i).getAlias()) {
         mapBuilder.put(computations.get(i).getAlias(), calculateResult);
       } else {
-        mapBuilder.put(computations.get(i).getDataField().getChild().getFirst().toString(), calculateResult);
+        mapBuilder.put(computations.get(i).getDataField().getChild().get(0).toString(), calculateResult);
       }
     }
     result = ExprTupleValue.fromExprValueMap(mapBuilder.buildKeepingLast());
diff --git a/ppl/src/main/java/org/opensearch/sql/ppl/utils/PPLQueryDataAnonymizer.java b/ppl/src/main/java/org/opensearch/sql/ppl/utils/PPLQueryDataAnonymizer.java
index 5b961b0f13..7e622489ba 100644
--- a/ppl/src/main/java/org/opensearch/sql/ppl/utils/PPLQueryDataAnonymizer.java
+++ b/ppl/src/main/java/org/opensearch/sql/ppl/utils/PPLQueryDataAnonymizer.java
@@ -224,7 +224,7 @@ public String visitHead(Head node, String context) {
 
   @Override
   public String visitTrendline(Trendline node, String context) {
-    String child = node.getChild().getFirst().accept(this, context);
+    String child = node.getChild().get(0).accept(this, context);
     String computations = visitExpressionList(node.getComputations());
     return StringUtils.format("%s | trendline %s", child, computations);
   }