feat: hive2 namespace supports dropTable (lance-format#10)

When using lance-spark with Hive2Namespace, we met error on saveAsTable.
It is because Hive2Namespace don't support dropTable operation which is
needed by saveAsTable.

---------

Co-authored-by: zhanghaobo@kanzhun.com <zhanghaobo@kanzhun.com>

Author: 2 people

java/lance-namespace-hive2/src/main/java/org/lance/namespace/hive2/Hive2Namespace.java

@@ -34,6 +34,8 @@
 import org.lance.namespace.model.DescribeTableResponse;
 import org.lance.namespace.model.DropNamespaceRequest;
 import org.lance.namespace.model.DropNamespaceResponse;
+import org.lance.namespace.model.DropTableRequest;
+import org.lance.namespace.model.DropTableResponse;
 import org.lance.namespace.model.ListNamespacesRequest;
 import org.lance.namespace.model.ListNamespacesResponse;
 import org.lance.namespace.model.ListTablesRequest;
@@ -264,6 +266,16 @@ public void tableExists(TableExistsRequest request) {
     Hive2Util.validateLanceTable(hmsTable.get());
   }
 
+  @Override
+  public DropTableResponse dropTable(DropTableRequest request) {
+    ObjectIdentifier tableId = ObjectIdentifier.of(request.getId());
+    String location = doDropTable(tableId);
+    DropTableResponse response = new DropTableResponse();
+    response.setId(request.getId());
+    response.setLocation(location);
+    return response;
+  }
+
   @Override
   public DescribeTableResponse describeTable(DescribeTableRequest request) {
     if (Boolean.TRUE.equals(request.getLoadDetailedMetadata())) {

java/lance-namespace-hive2/src/test/java/org/lance/namespace/hive2/TestHive2NamespaceIntegration.java

@@ -25,6 +25,7 @@
 import org.lance.namespace.model.DescribeTableRequest;
 import org.lance.namespace.model.DescribeTableResponse;
 import org.lance.namespace.model.DropNamespaceRequest;
+import org.lance.namespace.model.DropTableRequest;
 import org.lance.namespace.model.ListNamespacesRequest;
 import org.lance.namespace.model.ListNamespacesResponse;
 import org.lance.namespace.model.ListTablesRequest;
@@ -215,6 +216,19 @@ public void testTableOperations() {
     deregisterRequest.setId(Arrays.asList(testDatabase, tableName));
     namespace.deregisterTable(deregisterRequest);
 
+    // Verify table doesn't exist
+    assertThatThrownBy(() -> namespace.describeTable(describeRequest))
+        .isInstanceOf(LanceNamespaceException.class);
+
+    // Declare table again for dropping.
+    createResponse = namespace.declareTable(createRequest);
+    assertThat(createResponse.getLocation()).isNotNull();
+
+    // Drop table
+    DropTableRequest dropTableRequest = new DropTableRequest();
+    dropTableRequest.setId(Arrays.asList(testDatabase, tableName));
+    namespace.dropTable(dropTableRequest);
+
     // Verify table doesn't exist
     assertThatThrownBy(() -> namespace.describeTable(describeRequest))
         .isInstanceOf(LanceNamespaceException.class);