Parallelize TableLocation creation and address some interface cleanups (

#5432)

* Allow parallel TableLocation factory invocation in AbstractTableLocationProvider

* Delete ColumnLocation.getMetadata()

* Make AbstractTableLocation.loadDataIndex public

engine/table/src/main/java/io/deephaven/engine/table/impl/SourceTable.java

@@ -165,6 +165,7 @@ private void maybeAddLocations(@NotNull final Collection<ImmutableTableLocationK
             return;
         }
         filterLocationKeys(locationKeys)
+                .parallelStream()
                 .forEach(lk -> columnSourceManager.addLocation(locationProvider.getTableLocation(lk)));
     }
 

engine/table/src/main/java/io/deephaven/engine/table/impl/locations/ColumnLocation.java

@@ -11,7 +11,6 @@
 import io.deephaven.engine.table.impl.sources.regioned.*;
 import io.deephaven.util.type.NamedImplementation;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 /**
  * Per-TableLocation, per-column key, state, and factory object.
@@ -41,20 +40,6 @@ public interface ColumnLocation extends StringUtils.StringKeyedObject, NamedImpl
      */
     boolean exists();
 
-    /**
-     * <p>
-     * Get the metadata object stored with this column, or null if no such data exists.
-     * <p>
-     * Historically, this was typically a value to range map (grouping metadata). The value to range map, if non-null,
-     * is a map from unique (boxed) column values for this location to the associated ranges in which they occur. Ranges
-     * are either 2-element int[]s, or 2-element long[]s.
-     *
-     * @return The metadata stored with this column, or null if no such data exists
-     */
-    @SuppressWarnings("unused")
-    @Nullable
-    <METADATA_TYPE> METADATA_TYPE getMetadata(@NotNull ColumnDefinition<?> columnDefinition);
-
     /**
      * Get this column location cast to the specified type
      *

engine/table/src/main/java/io/deephaven/engine/table/impl/locations/impl/AbstractTableLocation.java

@@ -12,6 +12,7 @@
 import io.deephaven.engine.rowset.RowSet;
 import io.deephaven.hash.KeyedObjectHashMap;
 import io.deephaven.hash.KeyedObjectKey;
+import io.deephaven.util.annotations.InternalUseOnly;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -223,7 +224,10 @@ public final BasicDataIndex getDataIndex(@NotNull final String... columns) {
      *
      * @param columns The columns to load an index for
      * @return The data index, or {@code null} if none exists
+     * @apiNote This method is {@code public} for use in delegating implementations, and should not be called directly
+     *          otherwise.
      */
+    @InternalUseOnly
     @Nullable
-    protected abstract BasicDataIndex loadDataIndex(@NotNull String... columns);
+    public abstract BasicDataIndex loadDataIndex(@NotNull String... columns);
 }

engine/table/src/main/java/io/deephaven/engine/table/impl/locations/impl/AbstractTableLocationProvider.java

@@ -198,18 +198,18 @@ public TableLocation getTableLocationIfPresent(@NotNull final TableLocationKey t
         // See JavaDoc on tableLocations for background.
         // The intent is to create a TableLocation exactly once to replace the TableLocationKey placeholder that was
         // added in handleTableLocationKey.
-        if (current instanceof TableLocation) {
-            return (TableLocation) current;
-        }
-        synchronized (tableLocations) {
-            current = tableLocations.get(tableLocationKey);
-            if (current instanceof TableLocation) {
-                return (TableLocation) current;
+        if (!(current instanceof TableLocation)) {
+            final TableLocationKey immutableKey = (TableLocationKey) current;
+            // noinspection SynchronizationOnLocalVariableOrMethodParameter
+            synchronized (immutableKey) {
+                current = tableLocations.get(immutableKey);
+                if (immutableKey == current) {
+                    // Note, this may contend for the lock on tableLocations
+                    tableLocations.add(current = makeTableLocation(immutableKey));
+                }
             }
-            final TableLocation result = makeTableLocation((TableLocationKey) current);
-            tableLocations.add(result);
-            return result;
         }
+        return (TableLocation) current;
     }
 
     /**

engine/table/src/main/java/io/deephaven/engine/table/impl/locations/impl/NonexistentTableLocation.java

@@ -61,7 +61,7 @@ protected ColumnLocation makeColumnLocation(@NotNull final String name) {
 
     @Override
     @Nullable
-    protected BasicDataIndex loadDataIndex(@NotNull final String... columns) {
+    public BasicDataIndex loadDataIndex(@NotNull final String... columns) {
         throw new UnsupportedOperationException();
     }
 }

engine/table/src/test/java/io/deephaven/engine/table/impl/TestPartitioningColumns.java

@@ -183,12 +183,6 @@ public boolean exists() {
                     throw new UnsupportedOperationException();
                 }
 
-                @Nullable
-                @Override
-                public <METADATA_TYPE> METADATA_TYPE getMetadata(@NotNull final ColumnDefinition<?> columnDefinition) {
-                    throw new UnsupportedOperationException();
-                }
-
                 @Override
                 public ColumnRegionChar<Values> makeColumnRegionChar(
                         @NotNull final ColumnDefinition<?> columnDefinition) {
@@ -241,7 +235,8 @@ public <TYPE> ColumnRegionObject<TYPE, Values> makeColumnRegionObject(
         }
 
         @Override
-        protected @Nullable BasicDataIndex loadDataIndex(@NotNull final String... columns) {
+        @Nullable
+        public BasicDataIndex loadDataIndex(@NotNull final String... columns) {
             throw new UnsupportedOperationException();
         }
     }

engine/test-utils/src/main/java/io/deephaven/engine/testutil/locations/TableBackedColumnLocation.java

@@ -15,7 +15,6 @@
 import io.deephaven.engine.table.impl.sources.regioned.*;
 import io.deephaven.generic.region.*;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 public final class TableBackedColumnLocation
         extends AbstractColumnLocation
@@ -39,12 +38,6 @@ public boolean exists() {
         return columnSource != null;
     }
 
-    @Override
-    public <METADATA_TYPE> @Nullable METADATA_TYPE getMetadata(
-            @NotNull final ColumnDefinition<?> columnDefinition) {
-        return null;
-    }
-
     @Override
     public ColumnRegionChar<Values> makeColumnRegionChar(@NotNull final ColumnDefinition<?> columnDefinition) {
         return new AppendOnlyFixedSizePageRegionChar<>(

engine/test-utils/src/main/java/io/deephaven/engine/testutil/locations/TableBackedTableLocation.java

@@ -89,7 +89,7 @@ protected ColumnLocation makeColumnLocation(@NotNull final String name) {
 
     @Override
     @Nullable
-    protected BasicDataIndex loadDataIndex(@NotNull final String... columns) {
+    public BasicDataIndex loadDataIndex(@NotNull final String... columns) {
         return null;
     }
 }

extensions/parquet/table/src/main/java/io/deephaven/parquet/table/location/ParquetColumnLocation.java

@@ -120,12 +120,6 @@ private ParquetTableLocation tl() {
         return (ParquetTableLocation) getTableLocation();
     }
 
-    @Override
-    @Nullable
-    public <METADATA_TYPE> METADATA_TYPE getMetadata(@NotNull final ColumnDefinition<?> columnDefinition) {
-        return null;
-    }
-
     private <SOURCE, REGION_TYPE> REGION_TYPE makeColumnRegion(
             @NotNull final Function<ColumnDefinition<?>, SOURCE[]> sourceArrayFactory,
             @NotNull final ColumnDefinition<?> columnDefinition,

extensions/parquet/table/src/main/java/io/deephaven/parquet/table/location/ParquetTableLocation.java

@@ -243,8 +243,8 @@ private static boolean parquetFileExists(@NotNull final URI fileURI) {
         return !fileURI.getScheme().equals(FILE_URI_SCHEME) || Files.exists(Path.of(fileURI));
     }
 
-    @Nullable
     @Override
+    @Nullable
     public BasicDataIndex loadDataIndex(@NotNull final String... columns) {
         if (tableInfo == null) {
             return null;