Moved TableIdentifierComparator next to location key

extensions/iceberg/src/main/java/io/deephaven/iceberg/location/IcebergTableParquetLocationKey.java

@@ -5,7 +5,6 @@
 
 import io.deephaven.base.verify.Require;
 import io.deephaven.engine.table.impl.locations.TableLocationKey;
-import io.deephaven.iceberg.util.IcebergUtils;
 import io.deephaven.parquet.table.ParquetInstructions;
 import io.deephaven.parquet.table.location.ParquetTableLocationKey;
 import org.apache.iceberg.DataFile;
@@ -30,8 +29,8 @@ public class IcebergTableParquetLocationKey extends ParquetTableLocationKey impl
 
     private static final Comparator<String> CATALONG_NAME_COMPARATOR = Comparator.nullsFirst(Comparator.naturalOrder());
     private static final Comparator<UUID> UUID_COMPARATOR = Comparator.nullsFirst(Comparator.naturalOrder());
-    private static final Comparator<TableIdentifier> TABLE_ID_COMPARATOR =
-            Comparator.nullsFirst(IcebergUtils.TABLE_IDENTIFIER_COMPARATOR);
+    private static final Comparator<TableIdentifier> TABLE_IDENTIFIER_COMPARATOR =
+            Comparator.nullsFirst(TableIdentifierComparator.INSTANCE);
 
     @Nullable
     private final String catalogName;
@@ -157,7 +156,8 @@ public int compareTo(@NotNull final TableLocationKey other) {
             if ((comparisonResult = UUID_COMPARATOR.compare(tableUuid, otherTyped.tableUuid)) != 0) {
                 return comparisonResult;
             }
-            if ((comparisonResult = TABLE_ID_COMPARATOR.compare(tableIdentifier, otherTyped.tableIdentifier)) != 0) {
+            if ((comparisonResult =
+                    TABLE_IDENTIFIER_COMPARATOR.compare(tableIdentifier, otherTyped.tableIdentifier)) != 0) {
                 return comparisonResult;
             }
             if ((comparisonResult = Long.compare(dataSequenceNumber, otherTyped.dataSequenceNumber)) != 0) {

extensions/iceberg/src/main/java/io/deephaven/iceberg/location/TableIdentifierComparator.java

@@ -0,0 +1,44 @@
+//
+// Copyright (c) 2016-2024 Deephaven Data Labs and Patent Pending
+//
+package io.deephaven.iceberg.location;
+
+import org.apache.iceberg.catalog.Namespace;
+import org.apache.iceberg.catalog.TableIdentifier;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+enum TableIdentifierComparator implements Comparator<TableIdentifier> {
+    INSTANCE;
+
+    /**
+     * Compare two {@link TableIdentifier} instances.
+     * <p>
+     * Note that this method assumes:
+     * <ul>
+     * <li>There are just two fields {@link TableIdentifier#namespace()} and {@link TableIdentifier#name()} in
+     * {@link TableIdentifier} class, and both are not null for the objects being compared.</li>
+     * <li>There is just a single field {@link Namespace#levels()} in the {@link Namespace} class.</li>
+     * </ul>
+     * <p>
+     * {@inheritDoc}
+     *
+     * @param ti1 the first object to be compared.
+     * @param ti2 the second object to be compared.
+     * @return a negative integer, zero, or a positive integer as the first argument is less than, equal to, or greater
+     *         than the second, respectively.
+     */
+    @Override
+    public int compare(@NotNull final TableIdentifier ti1, @NotNull final TableIdentifier ti2) {
+        if (ti1 == ti2) {
+            return 0;
+        }
+        final int comparisonResult;
+        if ((comparisonResult = Arrays.compare(ti1.namespace().levels(), ti2.namespace().levels())) != 0) {
+            return comparisonResult;
+        }
+        return ti1.name().compareTo(ti2.name());
+    }
+}