feat: make java client builder generic (#2851)

In #2845 we ported the lancedb integration in lance-namespace to
lancedb. But that is too specific to RestNamespace. We can improve the
user entry point so that we can put local mode and future version of the
Flight SQL-based LanceDB server all behind this single
`LanceDbNamespaceClientBuilder` API.

Also I renamed `namespace` to `namesapceClient` to avoid confusion with
the namespace path.

docs/src/java/java.md

@@ -23,11 +23,11 @@ Add the following dependency to your `pom.xml`:
 ### Connecting to LanceDB Cloud
 
 ```java
-import com.lancedb.LanceDbRestNamespaceBuilder;
-import org.lance.namespace.RestNamespace;
+import com.lancedb.LanceDbNamespaceClientBuilder;
+import org.lance.namespace.LanceNamespace;
 
 // If your DB url is db://example-db, then your database here is example-db
-RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
     .apiKey("your_lancedb_cloud_api_key")
     .database("your_database_name")
     .build();
@@ -38,7 +38,7 @@ RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
 For LanceDB Enterprise deployments with a custom endpoint:
 
 ```java
-RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
     .apiKey("your_lancedb_enterprise_api_key")
     .database("your_database_name")
     .endpoint("<your_enterprise_endpoint>")
@@ -69,7 +69,7 @@ import org.lance.namespace.model.CreateNamespaceResponse;
 CreateNamespaceRequest request = new CreateNamespaceRequest();
 request.setId(Arrays.asList("my_namespace"));
 
-CreateNamespaceResponse response = namespace.createNamespace(request);
+CreateNamespaceResponse response = namespaceClient.createNamespace(request);
 ```
 
 You can also create nested namespaces:
@@ -79,7 +79,7 @@ You can also create nested namespaces:
 CreateNamespaceRequest request = new CreateNamespaceRequest();
 request.setId(Arrays.asList("parent_namespace", "child_namespace"));
 
-CreateNamespaceResponse response = namespace.createNamespace(request);
+CreateNamespaceResponse response = namespaceClient.createNamespace(request);
 ```
 
 ### Describing a Namespace
@@ -91,7 +91,7 @@ import org.lance.namespace.model.DescribeNamespaceResponse;
 DescribeNamespaceRequest request = new DescribeNamespaceRequest();
 request.setId(Arrays.asList("my_namespace"));
 
-DescribeNamespaceResponse response = namespace.describeNamespace(request);
+DescribeNamespaceResponse response = namespaceClient.describeNamespace(request);
 System.out.println("Namespace properties: " + response.getProperties());
 ```
 
@@ -105,7 +105,7 @@ import org.lance.namespace.model.ListNamespacesResponse;
 ListNamespacesRequest request = new ListNamespacesRequest();
 request.setId(Arrays.asList());  // Empty for root
 
-ListNamespacesResponse response = namespace.listNamespaces(request);
+ListNamespacesResponse response = namespaceClient.listNamespaces(request);
 for (String ns : response.getNamespaces()) {
     System.out.println("Namespace: " + ns);
 }
@@ -114,7 +114,7 @@ for (String ns : response.getNamespaces()) {
 ListNamespacesRequest childRequest = new ListNamespacesRequest();
 childRequest.setId(Arrays.asList("parent_namespace"));
 
-ListNamespacesResponse childResponse = namespace.listNamespaces(childRequest);
+ListNamespacesResponse childResponse = namespaceClient.listNamespaces(childRequest);
 ```
 
 ### Listing Tables
@@ -127,7 +127,7 @@ import org.lance.namespace.model.ListTablesResponse;
 ListTablesRequest request = new ListTablesRequest();
 request.setId(Arrays.asList("my_namespace"));
 
-ListTablesResponse response = namespace.listTables(request);
+ListTablesResponse response = namespaceClient.listTables(request);
 for (String table : response.getTables()) {
     System.out.println("Table: " + table);
 }
@@ -142,7 +142,7 @@ import org.lance.namespace.model.DropNamespaceResponse;
 DropNamespaceRequest request = new DropNamespaceRequest();
 request.setId(Arrays.asList("my_namespace"));
 
-DropNamespaceResponse response = namespace.dropNamespace(request);
+DropNamespaceResponse response = namespaceClient.dropNamespace(request);
 ```
 
 ### Describing a Table
@@ -154,7 +154,7 @@ import org.lance.namespace.model.DescribeTableResponse;
 DescribeTableRequest request = new DescribeTableRequest();
 request.setId(Arrays.asList("my_namespace", "my_table"));
 
-DescribeTableResponse response = namespace.describeTable(request);
+DescribeTableResponse response = namespaceClient.describeTable(request);
 System.out.println("Table version: " + response.getVersion());
 System.out.println("Schema fields: " + response.getSchema().getFields());
 ```
@@ -168,7 +168,7 @@ import org.lance.namespace.model.DropTableResponse;
 DropTableRequest request = new DropTableRequest();
 request.setId(Arrays.asList("my_namespace", "my_table"));
 
-DropTableResponse response = namespace.dropTable(request);
+DropTableResponse response = namespaceClient.dropTable(request);
 ```
 
 ## Writing Data
@@ -178,7 +178,7 @@ DropTableResponse response = namespace.dropTable(request);
 Tables are created within a namespace by providing data in Apache Arrow IPC format:
 
 ```java
-import org.lance.namespace.RestNamespace;
+import org.lance.namespace.LanceNamespace;
 import org.lance.namespace.model.CreateTableRequest;
 import org.lance.namespace.model.CreateTableResponse;
 import org.apache.arrow.memory.BufferAllocator;
@@ -245,7 +245,7 @@ try (BufferAllocator allocator = new RootAllocator();
     // Create table in a namespace
     CreateTableRequest request = new CreateTableRequest();
     request.setId(Arrays.asList("my_namespace", "my_table"));
-    CreateTableResponse response = namespace.createTable(request, tableData);
+    CreateTableResponse response = namespaceClient.createTable(request, tableData);
 }
 ```
 
@@ -262,7 +262,7 @@ InsertIntoTableRequest request = new InsertIntoTableRequest();
 request.setId(Arrays.asList("my_namespace", "my_table"));
 request.setMode(InsertIntoTableRequest.ModeEnum.APPEND);
 
-InsertIntoTableResponse response = namespace.insertIntoTable(request, insertData);
+InsertIntoTableResponse response = namespaceClient.insertIntoTable(request, insertData);
 System.out.println("New version: " + response.getVersion());
 ```
 
@@ -285,7 +285,7 @@ request.setUpdates(Arrays.asList(
     Arrays.asList("name", "'updated_name'")
 ));
 
-UpdateTableResponse response = namespace.updateTable(request);
+UpdateTableResponse response = namespaceClient.updateTable(request);
 System.out.println("Updated rows: " + response.getUpdatedRows());
 ```
 
@@ -303,7 +303,7 @@ request.setId(Arrays.asList("my_namespace", "my_table"));
 // Predicate to select rows to delete
 request.setPredicate("id > 100");
 
-DeleteFromTableResponse response = namespace.deleteFromTable(request);
+DeleteFromTableResponse response = namespaceClient.deleteFromTable(request);
 System.out.println("New version: " + response.getVersion());
 ```
 
@@ -330,7 +330,7 @@ request.setWhenMatchedUpdateAll(true);
 // Insert new rows when no match is found
 request.setWhenNotMatchedInsertAll(true);
 
-MergeInsertIntoTableResponse response = namespace.mergeInsertIntoTable(request, mergeData);
+MergeInsertIntoTableResponse response = namespaceClient.mergeInsertIntoTable(request, mergeData);
 
 System.out.println("Updated rows: " + response.getNumUpdatedRows());
 System.out.println("Inserted rows: " + response.getNumInsertedRows());
@@ -346,7 +346,7 @@ import org.lance.namespace.model.CountTableRowsRequest;
 CountTableRowsRequest request = new CountTableRowsRequest();
 request.setId(Arrays.asList("my_namespace", "my_table"));
 
-Long rowCount = namespace.countTableRows(request);
+Long rowCount = namespaceClient.countTableRows(request);
 System.out.println("Row count: " + rowCount);
 ```
 
@@ -373,7 +373,7 @@ query.setVector(vector);
 query.setColumns(Arrays.asList("id", "name", "embedding"));
 
 // Execute query - returns Arrow IPC format
-byte[] result = namespace.queryTable(query);
+byte[] result = namespaceClient.queryTable(query);
 ```
 
 ### Full Text Search
@@ -399,7 +399,7 @@ query.setFullTextQuery(fts);
 // Specify columns to return
 query.setColumns(Arrays.asList("id", "text_column"));
 
-byte[] result = namespace.queryTable(query);
+byte[] result = namespaceClient.queryTable(query);
 ```
 
 ### Query with Filter
@@ -411,7 +411,7 @@ query.setK(10);
 query.setFilter("id > 50");
 query.setColumns(Arrays.asList("id", "name"));
 
-byte[] result = namespace.queryTable(query);
+byte[] result = namespaceClient.queryTable(query);
 ```
 
 ### Query with Prefilter
@@ -428,7 +428,7 @@ QueryTableRequestVector vector = new QueryTableRequestVector();
 vector.setSingleVector(queryVector);
 query.setVector(vector);
 
-byte[] result = namespace.queryTable(query);
+byte[] result = namespaceClient.queryTable(query);
 ```
 
 ### Reading Query Results
@@ -475,7 +475,7 @@ class ByteArraySeekableByteChannel implements SeekableByteChannel {
 }
 
 // Read query results
-byte[] queryResult = namespace.queryTable(query);
+byte[] queryResult = namespaceClient.queryTable(query);
 
 try (BufferAllocator allocator = new RootAllocator();
      ArrowFileReader reader = new ArrowFileReader(

java/README.md

@@ -7,11 +7,11 @@
 For LanceDB Cloud, use the simplified builder API:
 
 ```java
-import com.lancedb.LanceDbRestNamespaceBuilder;
-import org.lance.namespace.RestNamespace;
+import com.lancedb.LanceDbNamespaceClientBuilder;
+import org.lance.namespace.LanceNamespace;
 
 // If your DB url is db://example-db, then your database here is example-db
-RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
     .apiKey("your_lancedb_cloud_api_key")
     .database("your_database_name")
     .build();
@@ -22,7 +22,7 @@ RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
 For Enterprise deployments, use your custom endpoint:
 
 ```java
-RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
     .apiKey("your_lancedb_enterprise_api_key")
     .database("your_database_name")
     .endpoint("<your_enterprise_endpoint>")

java/lancedb-core/src/main/java/com/lancedb/LanceDbNamespaceClientBuilder.java

@@ -13,22 +13,22 @@
  */
 package com.lancedb;
 
-import org.lance.namespace.RestNamespace;
+import org.lance.namespace.LanceNamespace;
 
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
 
 /**
- * Util class to help construct a {@link RestNamespace} for LanceDB.
+ * Util class to help construct a {@link LanceNamespace} for LanceDB.
  *
  * <p>For LanceDB Cloud, use the simplified builder API:
  *
  * <pre>{@code
- * import org.lance.namespace.RestNamespace;
+ * import org.lance.namespace.LanceNamespace;
  *
  * // If your DB url is db://example-db, then your database here is example-db
- * RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+ * LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
  *     .apiKey("your_lancedb_cloud_api_key")
  *     .database("your_database_name")
  *     .build();
@@ -37,14 +37,14 @@ import java.util.Optional;
  * <p>For LanceDB Enterprise deployments, use your custom endpoint:
  *
  * <pre>{@code
- * RestNamespace namespace = LanceDbRestNamespaceBuilder.newBuilder()
+ * LanceNamespace namespaceClient = LanceDbNamespaceClientBuilder.newBuilder()
  *     .apiKey("your_lancedb_enterprise_api_key")
  *     .database("your_database_name")
  *     .endpoint("<your_enterprise_endpoint>")
  *     .build();
  * }</pre>
  */
-public class LanceDbRestNamespaceBuilder {
+public class LanceDbNamespaceClientBuilder {
   private static final String DEFAULT_REGION = "us-east-1";
   private static final String CLOUD_URL_PATTERN = "https://%s.%s.api.lancedb.com";
 
@@ -54,15 +54,15 @@ public class LanceDbRestNamespaceBuilder {
   private Optional<String> region = Optional.empty();
   private Map<String, String> additionalConfig = new HashMap<>();
 
-  private LanceDbRestNamespaceBuilder() {}
+  private LanceDbNamespaceClientBuilder() {}
 
   /**
    * Create a new builder instance.
    *
-   * @return A new RestNamespaceBuilder
+   * @return A new LanceDbNamespaceClientBuilder
    */
-  public static LanceDbRestNamespaceBuilder newBuilder() {
-    return new LanceDbRestNamespaceBuilder();
+  public static LanceDbNamespaceClientBuilder newBuilder() {
+    return new LanceDbNamespaceClientBuilder();
   }
 
   /**
@@ -71,7 +71,7 @@ public class LanceDbRestNamespaceBuilder {
    * @param apiKey The LanceDB API key
    * @return This builder
    */
-  public LanceDbRestNamespaceBuilder apiKey(String apiKey) {
+  public LanceDbNamespaceClientBuilder apiKey(String apiKey) {
     if (apiKey == null || apiKey.trim().isEmpty()) {
       throw new IllegalArgumentException("API key cannot be null or empty");
     }
@@ -85,7 +85,7 @@ public class LanceDbRestNamespaceBuilder {
    * @param database The database name
    * @return This builder
    */
-  public LanceDbRestNamespaceBuilder database(String database) {
+  public LanceDbNamespaceClientBuilder database(String database) {
     if (database == null || database.trim().isEmpty()) {
       throw new IllegalArgumentException("Database cannot be null or empty");
     }
@@ -100,7 +100,7 @@ public class LanceDbRestNamespaceBuilder {
    * @param endpoint The complete base URL for your LanceDB Enterprise deployment
    * @return This builder
    */
-  public LanceDbRestNamespaceBuilder endpoint(String endpoint) {
+  public LanceDbNamespaceClientBuilder endpoint(String endpoint) {
     this.endpoint = Optional.ofNullable(endpoint);
     return this;
   }
@@ -112,7 +112,7 @@ public class LanceDbRestNamespaceBuilder {
    * @param region The AWS region (e.g., "us-east-1", "eu-west-1")
    * @return This builder
    */
-  public LanceDbRestNamespaceBuilder region(String region) {
+  public LanceDbNamespaceClientBuilder region(String region) {
     this.region = Optional.ofNullable(region);
     return this;
   }
@@ -124,18 +124,18 @@ public class LanceDbRestNamespaceBuilder {
    * @param value The configuration value
    * @return This builder
    */
-  public LanceDbRestNamespaceBuilder config(String key, String value) {
+  public LanceDbNamespaceClientBuilder config(String key, String value) {
     this.additionalConfig.put(key, value);
     return this;
   }
 
   /**
-   * Build the Lance RestNamespace instance.
+   * Build the LanceNamespace instance.
    *
-   * @return A configured Lance RestNamespace
+   * @return A configured LanceNamespace
    * @throws IllegalStateException if required parameters are missing
    */
-  public RestNamespace build() {
+  public LanceNamespace build() {
     // Validate required fields
     if (apiKey == null) {
       throw new IllegalStateException("API key is required");
@@ -158,8 +158,7 @@ public class LanceDbRestNamespaceBuilder {
       uri = String.format(CLOUD_URL_PATTERN, database, effectiveRegion);
     }
     config.put("uri", uri);
-    RestNamespace ns = new RestNamespace();
-    ns.initialize(config, null);
-    return ns;
+
+    return LanceNamespace.connect("rest", config, null);
   }
 }

java/lancedb-core/src/test/java/com/lancedb/LanceDbNamespaceClientBuilderTest.java

@@ -17,13 +17,13 @@ import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
 
-/** Unit tests for LanceDbRestNamespaceBuilder. */
-public class LanceDbRestNamespaceBuilderTest {
+/** Unit tests for LanceDbNamespaceClientBuilder. */
+public class LanceDbNamespaceClientBuilderTest {
 
   @Test
   public void testBuilderRequiresApiKey() {
-    LanceDbRestNamespaceBuilder builder =
-        LanceDbRestNamespaceBuilder.newBuilder().database("test-db");
+    LanceDbNamespaceClientBuilder builder =
+        LanceDbNamespaceClientBuilder.newBuilder().database("test-db");
 
     IllegalStateException exception = assertThrows(IllegalStateException.class, builder::build);
     assertEquals("API key is required", exception.getMessage());
@@ -31,8 +31,8 @@ public class LanceDbRestNamespaceBuilderTest {
 
   @Test
   public void testBuilderRequiresDatabase() {
-    LanceDbRestNamespaceBuilder builder =
-        LanceDbRestNamespaceBuilder.newBuilder().apiKey("test-api-key");
+    LanceDbNamespaceClientBuilder builder =
+        LanceDbNamespaceClientBuilder.newBuilder().apiKey("test-api-key");
 
     IllegalStateException exception = assertThrows(IllegalStateException.class, builder::build);
     assertEquals("Database is required", exception.getMessage());
@@ -43,7 +43,7 @@ public class LanceDbRestNamespaceBuilderTest {
     IllegalArgumentException exception =
         assertThrows(
             IllegalArgumentException.class,
-            () -> LanceDbRestNamespaceBuilder.newBuilder().apiKey(null));
+            () -> LanceDbNamespaceClientBuilder.newBuilder().apiKey(null));
     assertEquals("API key cannot be null or empty", exception.getMessage());
   }
 
@@ -52,7 +52,7 @@ public class LanceDbRestNamespaceBuilderTest {
     IllegalArgumentException exception =
         assertThrows(
             IllegalArgumentException.class,
-            () -> LanceDbRestNamespaceBuilder.newBuilder().apiKey("  "));
+            () -> LanceDbNamespaceClientBuilder.newBuilder().apiKey("  "));
     assertEquals("API key cannot be null or empty", exception.getMessage());
   }
 
@@ -61,7 +61,7 @@ public class LanceDbRestNamespaceBuilderTest {
     IllegalArgumentException exception =
         assertThrows(
             IllegalArgumentException.class,
-            () -> LanceDbRestNamespaceBuilder.newBuilder().database(null));
+            () -> LanceDbNamespaceClientBuilder.newBuilder().database(null));
     assertEquals("Database cannot be null or empty", exception.getMessage());
   }
 
@@ -70,14 +70,14 @@ public class LanceDbRestNamespaceBuilderTest {
     IllegalArgumentException exception =
         assertThrows(
             IllegalArgumentException.class,
-            () -> LanceDbRestNamespaceBuilder.newBuilder().database("  "));
+            () -> LanceDbNamespaceClientBuilder.newBuilder().database("  "));
     assertEquals("Database cannot be null or empty", exception.getMessage());
   }
 
   @Test
   public void testBuilderFluentApi() {
     // Verify the builder returns itself for chaining
-    LanceDbRestNamespaceBuilder builder = LanceDbRestNamespaceBuilder.newBuilder();
+    LanceDbNamespaceClientBuilder builder = LanceDbNamespaceClientBuilder.newBuilder();
 
     assertSame(builder, builder.apiKey("test-key"));
     assertSame(builder, builder.database("test-db"));
@@ -88,8 +88,8 @@ public class LanceDbRestNamespaceBuilderTest {
 
   @Test
   public void testNewBuilderCreatesNewInstance() {
-    LanceDbRestNamespaceBuilder builder1 = LanceDbRestNamespaceBuilder.newBuilder();
-    LanceDbRestNamespaceBuilder builder2 = LanceDbRestNamespaceBuilder.newBuilder();
+    LanceDbNamespaceClientBuilder builder1 = LanceDbNamespaceClientBuilder.newBuilder();
+    LanceDbNamespaceClientBuilder builder2 = LanceDbNamespaceClientBuilder.newBuilder();
 
     assertNotSame(builder1, builder2);
   }