New approach

tanclary · Jan 30, 2024 · 0ec73b1 · 0ec73b1
1 parent b88eb0f
commit 0ec73b1
Showing 1 changed file with 21 additions and 13 deletions.
diff --git a/core/src/main/java/org/apache/calcite/sql/dialect/SnowflakeSqlDialect.java b/core/src/main/java/org/apache/calcite/sql/dialect/SnowflakeSqlDialect.java
@@ -26,7 +26,7 @@
 import org.apache.calcite.sql.fun.SqlStdOperatorTable;
 import org.apache.calcite.sql.parser.SqlParserPos;
 
-import java.util.HashMap;
+import com.google.common.collect.ImmutableMap;
 
 /**
  * A <code>SqlDialect</code> implementation for the Snowflake database.
@@ -40,27 +40,35 @@ public class SnowflakeSqlDialect extends SqlDialect {
   public static final SqlDialect DEFAULT =
       new SnowflakeSqlDialect(DEFAULT_CONTEXT);
 
+  /* Maps a SqlKind to its Snowflake-specific operator. */
+  public static final ImmutableMap<SqlKind, SqlOperator> OPERATOR_MAP;
+
+  static {
+    final ImmutableMap.Builder<SqlKind, SqlOperator> builder =
+        ImmutableMap.builder();
+    builder.put(SqlKind.BIT_AND, SqlLibraryOperators.BITAND_AGG);
+    builder.put(SqlKind.BIT_OR, SqlLibraryOperators.BITOR_AGG);
+    builder.put(SqlKind.CHAR_LENGTH, SqlLibraryOperators.LENGTH);
+    builder.put(SqlKind.ENDS_WITH, SqlLibraryOperators.ENDSWITH);
+    builder.put(SqlKind.STARTS_WITH, SqlLibraryOperators.STARTSWITH);
+    builder.put(SqlKind.MAX, SqlStdOperatorTable.MAX);
+    builder.put(SqlKind.MIN, SqlStdOperatorTable.MIN);
+    OPERATOR_MAP = builder.build();
+  }
+
   /** Creates a SnowflakeSqlDialect. */
   public SnowflakeSqlDialect(Context context) {
     super(context);
   }
 
   @Override public void unparseCall(final SqlWriter writer, final SqlCall call, final int leftPrec,
       final int rightPrec) {
-    final HashMap<SqlKind, SqlOperator> map = new HashMap<>();
-    map.put(SqlKind.BIT_AND, SqlLibraryOperators.BITAND_AGG);
-    map.put(SqlKind.BIT_OR, SqlLibraryOperators.BITOR_AGG);
-    map.put(SqlKind.CHAR_LENGTH, SqlLibraryOperators.LENGTH);
-    map.put(SqlKind.ENDS_WITH, SqlLibraryOperators.ENDSWITH);
-    map.put(SqlKind.STARTS_WITH, SqlLibraryOperators.STARTSWITH);
-    map.put(SqlKind.MAX, SqlStdOperatorTable.MAX);
-    map.put(SqlKind.MIN, SqlStdOperatorTable.MIN);
-    SqlOperator op = map.get(call.getKind());
+    SqlOperator op = OPERATOR_MAP.get(call.getKind());
     if (op != null) {
-        SqlCall newCall = op.createCall(SqlParserPos.ZERO, call.getOperandList());
-        super.unparseCall(writer, newCall, leftPrec, rightPrec);
+      SqlCall newCall = op.createCall(SqlParserPos.ZERO, call.getOperandList());
+      super.unparseCall(writer, newCall, leftPrec, rightPrec);
     } else {
-        super.unparseCall(writer, call, leftPrec, rightPrec);
+      super.unparseCall(writer, call, leftPrec, rightPrec);
     }
   }