add sqlexception handling and proper cancellation

Author: keshavdandeva

java-bigquery-jdbc/src/main/java/com/google/cloud/bigquery/jdbc/BigQueryDatabaseMetaData.java

@@ -5078,8 +5078,13 @@ private void processSingleTable(
       FieldList resultSchemaFields,
       TableProcessor processor)
       throws SQLException {
-    Table bqTable =
-        bigquery.getTable(TableId.of(datasetId.getProject(), datasetId.getDataset(), tableName));
+    Table bqTable;
+    try {
+      bqTable =
+          bigquery.getTable(TableId.of(datasetId.getProject(), datasetId.getDataset(), tableName));
+    } catch (Exception e) {
+      throw new SQLException("Error while fetching table metadata: " + e.getMessage(), e);
+    }
     if (bqTable != null && bqTable.getDefinition() != null) {
       processor.process(bqTable, collectedResults, resultSchemaFields);
     }
@@ -5101,20 +5106,21 @@ private void processTargetTablesConcurrently(
     ExecutorService executor = connection.getMetadataExecutor();
     List<Future<?>> taskFutures = new ArrayList<>();
 
-    for (DatasetId datasetId : targetDatasets) {
-      taskFutures.add(
-          executor.submit(
-              () -> {
-                processSingleTable(
-                    datasetId, tableName, collectedResults, resultSchemaFields, processor);
-                return null;
-              }));
-    }
-
     try {
+      for (DatasetId datasetId : targetDatasets) {
+        taskFutures.add(
+            executor.submit(
+                () -> {
+                  processSingleTable(
+                      datasetId, tableName, collectedResults, resultSchemaFields, processor);
+                  return null;
+                }));
+      }
       waitForTasksCompletion(taskFutures);
     } catch (ExecutionException e) {
       throw new SQLException("Error while fetching metadata", e);
+    } finally {
+      taskFutures.forEach(future -> future.cancel(true));
     }
   }
 }

java-bigquery-jdbc/src/test/java/com/google/cloud/bigquery/jdbc/BigQueryDatabaseMetaDataTest.java

@@ -159,7 +159,6 @@ public void testBigqueryDatabaseMetaDataGetters() throws SQLException {
     assertEquals("Project", dbMetadata.getCatalogTerm());
   }
 
-
   @Test
   public void testNeedsListing() {
     assertTrue(dbMetadata.needsListing(null), "Null pattern should require listing");
@@ -3233,7 +3232,6 @@ public void testWrapperMethods() throws SQLException {
     assertThat((Throwable) e).hasMessageThat().contains("Cannot unwrap to java.sql.Connection");
   }
 
-
   @ParameterizedTest
   @EnumSource(StandardSQLTypeName.class)
   public void testMetadataAndResultSetMetadataTypeMappingConsistency(StandardSQLTypeName type) {