fix IT with syntax 21

Signed-off-by: xinyual <xinyual@amazon.com>

Author: xinyual

core/src/main/java/org/opensearch/sql/ast/tree/Join.java

@@ -48,18 +48,21 @@ public Join(
   public UnresolvedPlan attach(UnresolvedPlan child) {
     // attach child to left, meanwhile fill back side aliases if possible.
     if (leftAlias.isPresent()) {
-      if (child instanceof SubqueryAlias alias) {
-        this.left = new SubqueryAlias(leftAlias.get(), alias.getChild().getFirst());
+      if (child instanceof SubqueryAlias) {
+        SubqueryAlias alias = (SubqueryAlias) child;
+        this.left = new SubqueryAlias(leftAlias.get(), alias.getChild().get(0));
       } else {
         this.left = new SubqueryAlias(leftAlias.get(), child);
       }
     } else {
-      if (child instanceof SubqueryAlias alias) {
+      if (child instanceof SubqueryAlias) {
+        SubqueryAlias alias = (SubqueryAlias) child;
         leftAlias = Optional.of(alias.getAlias());
       }
       this.left = child;
     }
-    if (rightAlias.isEmpty() && this.right instanceof SubqueryAlias alias) {
+    if (rightAlias.isEmpty() && this.right instanceof SubqueryAlias) {
+      SubqueryAlias alias = (SubqueryAlias) this.right;
       rightAlias = Optional.of(alias.getAlias());
     }
     return this;

core/src/main/java/org/opensearch/sql/calcite/CalciteRelNodeVisitor.java

@@ -671,7 +671,7 @@ public RelNode visitJoin(Join node, CalcitePlanContext context) {
       // If the plan convert to Spark plan, and there are two table1: database1.table1 and
       // database2.table1. The query with column `table1.id` can only be resolved in the namespace
       // of "database1". User should run `using database1` before the query which access `table1.id`
-      String rightTableQualifiedName = rightTableName.getLast();
+      String rightTableQualifiedName = rightTableName.get(rightTableName.size() - 1);
       // new columns with alias or table;
       List<String> rightColumnsWithAliasIfConflict =
           rightColumns.stream()
@@ -682,7 +682,7 @@ public RelNode visitJoin(Join node, CalcitePlanContext context) {
                               .map(a -> a + "." + col)
                               .orElse(rightTableQualifiedName + "." + col)
                           : col)
-              .toList();
+                  .collect(Collectors.toList());
       context.relBuilder.join(
           JoinAndLookupUtils.translateJoinType(node.getJoinType()), joinCondition);
       JoinAndLookupUtils.renameToExpectedFields(

core/src/main/java/org/opensearch/sql/calcite/CalciteRexNodeVisitor.java

@@ -288,8 +288,8 @@ public RexNode visitQualifiedName(QualifiedName node, CalcitePlanContext context
           // Similar to the step 2.3.
           List<String> candidates =
               context.relBuilder.peek(1).getRowType().getFieldNames().stream()
-                  .filter(col -> substringAfterLast(col, ".").equals(parts.getLast()))
-                  .toList();
+                  .filter(col -> substringAfterLast(col, ".").equals(parts.get(parts.size() - 1)))
+                      .collect(Collectors.toList());
           for (String candidate : candidates) {
             try {
               // field("nation2", "n2.n_name"); // pass
@@ -332,8 +332,8 @@ public RexNode visitQualifiedName(QualifiedName node, CalcitePlanContext context
         // Build the candidates which contains `n_name`: e.g. `(nation1.)n_name`, `n2.n_name`
         List<String> candidates =
             context.relBuilder.peek().getRowType().getFieldNames().stream()
-                .filter(col -> substringAfterLast(col, ".").equals(parts.getLast()))
-                .toList();
+                .filter(col -> substringAfterLast(col, ".").equals(parts.get(parts.size() - 1)))
+                    .collect(Collectors.toList());
         for (String candidate : candidates) {
           try {
             // field("nation2", "n2.n_name"); // pass

ppl/src/main/java/org/opensearch/sql/ppl/parser/AstBuilder.java

@@ -701,12 +701,13 @@ private String getTextInQuery(ParserRuleContext ctx) {
   private UnresolvedPlan projectExceptMeta(UnresolvedPlan plan) {
     if ((plan instanceof Project) && !((Project) plan).isExcluded()) {
       return plan;
-    } else if (plan instanceof SubqueryAlias subqueryAlias) {
+    } else if (plan instanceof SubqueryAlias) {
+      SubqueryAlias subqueryAlias = (SubqueryAlias) plan;
       // don't wrap subquery alias with project, wrap its child
       return new SubqueryAlias(
           subqueryAlias.getAlias(),
           new Project(ImmutableList.of(AllFieldsExcludeMeta.of()))
-              .attach(subqueryAlias.getChild().getFirst()));
+              .attach(subqueryAlias.getChild().get(0)));
     } else {
       return new Project(ImmutableList.of(AllFieldsExcludeMeta.of())).attach(plan);
     }