refactor(samples): modernize Admin API examples to use auto-generated GAPIC client

Refactors the Bigtable Admin API Java samples to use the modern, auto-generated proto-based methods via `getBaseClient()`. This aligns the samples with the ongoing effort to freeze the legacy handwritten
client and encourage the use of the underlying GAPIC client.

Specific changes:
* Updated `HelloWorld.java`, `TableAdminExample.java`, and `InstanceAdminExample.java` to call methods on the base GAPIC client instead of the legacy wrappers.
* Replaced legacy wrapper models with standard protobuf request objects (e.g., `com.google.bigtable.admin.v2.CreateTableRequest`, `com.google.bigtable.admin.v2.Instance`).
* Updated resource name strings to fully qualified formats (e.g., `projects/{project}/instances/{instance}`).
* Migrated garbage collection rule definitions to use the newly introduced `GcRuleBuilder`.
* Updated `InstanceAdminExampleTest.java` to remain compatible with the modified sample return types.

Tracking Bug: b/475818901

Author: jinseopkim0

samples/snippets/src/main/java/com/example/bigtable/HelloWorld.java

@@ -24,7 +24,6 @@
 import com.google.api.gax.rpc.ServerStream;
 import com.google.cloud.bigtable.admin.v2.BigtableTableAdminClient;
 import com.google.cloud.bigtable.admin.v2.BigtableTableAdminSettings;
-import com.google.cloud.bigtable.admin.v2.models.CreateTableRequest;
 import com.google.cloud.bigtable.data.v2.BigtableDataClient;
 import com.google.cloud.bigtable.data.v2.BigtableDataSettings;
 import com.google.cloud.bigtable.data.v2.models.Filters.Filter;
@@ -60,6 +59,8 @@ public class HelloWorld {
   private static final String COLUMN_QUALIFIER_GREETING = "greeting";
   private static final String COLUMN_QUALIFIER_NAME = "name";
   private static final String ROW_KEY_PREFIX = "rowKey";
+  private final String projectId;
+  private final String instanceId;
   private final String tableId;
   private final BigtableDataClient dataClient;
   private final BigtableTableAdminClient adminClient;
@@ -78,6 +79,8 @@ public static void main(String[] args) throws Exception {
   }
 
   public HelloWorld(String projectId, String instanceId, String tableId) throws IOException {
+    this.projectId = projectId;
+    this.instanceId = instanceId;
     this.tableId = tableId;
 
     // [START bigtable_hw_connect]
@@ -122,9 +125,19 @@ public void createTable() {
     // Checks if table exists, creates table if does not exist.
     if (!adminClient.exists(tableId)) {
       System.out.println("Creating table: " + tableId);
-      CreateTableRequest createTableRequest =
-          CreateTableRequest.of(tableId).addFamily(COLUMN_FAMILY);
-      adminClient.createTable(createTableRequest);
+      String parent = "projects/" + projectId + "/instances/" + instanceId;
+      com.google.bigtable.admin.v2.CreateTableRequest request =
+          com.google.bigtable.admin.v2.CreateTableRequest.newBuilder()
+              .setParent(parent)
+              .setTableId(tableId)
+              .setTable(
+                  com.google.bigtable.admin.v2.Table.newBuilder()
+                      .putColumnFamilies(
+                          COLUMN_FAMILY,
+                          com.google.bigtable.admin.v2.ColumnFamily.getDefaultInstance())
+                      .build())
+              .build();
+      adminClient.getBaseClient().createTable(request);
       System.out.printf("Table %s created successfully%n", tableId);
     }
     // [END bigtable_hw_create_table]
@@ -255,7 +268,8 @@ public void deleteTable() {
     // [START bigtable_hw_delete_table]
     System.out.println("\nDeleting table: " + tableId);
     try {
-      adminClient.deleteTable(tableId);
+      String tableName = "projects/" + projectId + "/instances/" + instanceId + "/tables/" + tableId;
+      adminClient.getBaseClient().deleteTable(tableName);
       System.out.printf("Table %s deleted successfully%n", tableId);
     } catch (NotFoundException e) {
       System.err.println("Failed to delete a non-existent table: " + e.getMessage());

samples/snippets/src/main/java/com/example/bigtable/InstanceAdminExample.java

@@ -18,16 +18,22 @@
 
 import com.google.api.gax.rpc.AlreadyExistsException;
 import com.google.api.gax.rpc.NotFoundException;
+import com.google.bigtable.admin.v2.Cluster;
+import com.google.bigtable.admin.v2.CreateClusterRequest;
+import com.google.bigtable.admin.v2.CreateInstanceRequest;
+import com.google.bigtable.admin.v2.DeleteClusterRequest;
+import com.google.bigtable.admin.v2.DeleteInstanceRequest;
+import com.google.bigtable.admin.v2.GetClusterRequest;
+import com.google.bigtable.admin.v2.GetInstanceRequest;
+import com.google.bigtable.admin.v2.Instance;
+import com.google.bigtable.admin.v2.ListClustersRequest;
+import com.google.bigtable.admin.v2.ListClustersResponse;
+import com.google.bigtable.admin.v2.ListInstancesRequest;
+import com.google.bigtable.admin.v2.ListInstancesResponse;
+import com.google.bigtable.admin.v2.StorageType;
 import com.google.cloud.bigtable.admin.v2.BigtableInstanceAdminClient;
 import com.google.cloud.bigtable.admin.v2.BigtableInstanceAdminSettings;
-import com.google.cloud.bigtable.admin.v2.models.Cluster;
-import com.google.cloud.bigtable.admin.v2.models.CreateClusterRequest;
-import com.google.cloud.bigtable.admin.v2.models.CreateInstanceRequest;
-import com.google.cloud.bigtable.admin.v2.models.Instance;
-import com.google.cloud.bigtable.admin.v2.models.PartialListInstancesException;
-import com.google.cloud.bigtable.admin.v2.models.StorageType;
 import java.io.IOException;
-import java.util.List;
 import java.util.Map;
 
 /**
@@ -49,6 +55,7 @@
 public class InstanceAdminExample {
 
   private static final String CLUSTER = "cluster";
+  private final String projectId;
   private final String clusterId;
   private final String instanceId;
   private final BigtableInstanceAdminClient adminClient;
@@ -68,6 +75,7 @@ public static void main(String[] args) throws IOException {
 
   public InstanceAdminExample(String projectId, String instanceId, String clusterId)
       throws IOException {
+    this.projectId = projectId;
     this.instanceId = instanceId;
     this.clusterId = clusterId;
 
@@ -103,18 +111,33 @@ public void createProdInstance() {
       // [START bigtable_create_prod_instance]
       // Creates a Production Instance with the ID "ssd-instance",
       // cluster id "ssd-cluster", 3 nodes and location "us-central1-f".
-      CreateInstanceRequest createInstanceRequest =
-          CreateInstanceRequest.of(instanceId)
-              .addCluster(clusterId, "us-central1-f", 3, StorageType.SSD)
+      String parent = "projects/" + projectId;
+      Instance instanceObj =
+          Instance.newBuilder()
+              .setDisplayName(instanceId)
               .setType(Instance.Type.PRODUCTION)
-              .addLabel("department", "accounting");
+              .putLabels("department", "accounting")
+              .build();
+      Cluster clusterObj =
+          Cluster.newBuilder()
+              .setLocation("projects/" + projectId + "/locations/us-central1-f")
+              .setServeNodes(3)
+              .setDefaultStorageType(StorageType.SSD)
+              .build();
+      CreateInstanceRequest request =
+          CreateInstanceRequest.newBuilder()
+              .setParent(parent)
+              .setInstanceId(instanceId)
+              .setInstance(instanceObj)
+              .putClusters(clusterId, clusterObj)
+              .build();
       // Creates a production instance with the given request.
       try {
-        Instance instance = adminClient.createInstance(createInstanceRequest);
-        System.out.printf("PRODUCTION type instance %s created successfully%n", instance.getId());
+        Instance instance = adminClient.getBaseClient().createInstanceAsync(request).get();
+        System.out.printf("PRODUCTION type instance %s created successfully%n", instance.getName());
       } catch (Exception e) {
         System.err.println("Failed to create instance: " + e.getMessage());
-        throw e;
+        throw new RuntimeException(e);
       }
       // [END bigtable_create_prod_instance]
     }
@@ -125,14 +148,14 @@ public void listInstances() {
     System.out.println("\nListing Instances");
     // [START bigtable_list_instances]
     try {
-      List<Instance> instances = adminClient.listInstances();
-      for (Instance instance : instances) {
-        System.out.println(instance.getId());
+      String parent = "projects/" + projectId;
+      ListInstancesRequest request = ListInstancesRequest.newBuilder().setParent(parent).build();
+      ListInstancesResponse response = adminClient.getBaseClient().listInstances(request);
+      for (Instance instance : response.getInstancesList()) {
+        System.out.println(instance.getName());
       }
-    } catch (PartialListInstancesException e) {
+    } catch (Exception e) {
       System.err.println("Failed to list instances: " + e.getMessage());
-      System.err.println("The following zones are unavailable: " + e.getUnavailableZones());
-      System.err.println("But the following instances are reachable: " + e.getInstances());
     }
     // [END bigtable_list_instances]
   }
@@ -143,11 +166,13 @@ public Instance getInstance() {
     // [START bigtable_get_instance]
     Instance instance = null;
     try {
-      instance = adminClient.getInstance(instanceId);
-      System.out.println("Instance ID: " + instance.getId());
+      String name = "projects/" + projectId + "/instances/" + instanceId;
+      GetInstanceRequest request = GetInstanceRequest.newBuilder().setName(name).build();
+      instance = adminClient.getBaseClient().getInstance(request);
+      System.out.println("Instance ID: " + instance.getName());
       System.out.println("Display Name: " + instance.getDisplayName());
       System.out.print("Labels: ");
-      Map<String, String> labels = instance.getLabels();
+      Map<String, String> labels = instance.getLabelsMap();
       for (String key : labels.keySet()) {
         System.out.printf("%s - %s", key, labels.get(key));
       }
@@ -165,9 +190,11 @@ public void listClusters() {
     System.out.println("\nListing Clusters");
     // [START bigtable_get_clusters]
     try {
-      List<Cluster> clusters = adminClient.listClusters(instanceId);
-      for (Cluster cluster : clusters) {
-        System.out.println(cluster.getId());
+      String parent = "projects/" + projectId + "/instances/" + instanceId;
+      ListClustersRequest request = ListClustersRequest.newBuilder().setParent(parent).build();
+      ListClustersResponse response = adminClient.getBaseClient().listClusters(request);
+      for (Cluster cluster : response.getClustersList()) {
+        System.out.println(cluster.getName());
       }
     } catch (NotFoundException e) {
       System.err.println("Failed to list clusters from a non-existent instance: " + e.getMessage());
@@ -180,7 +207,9 @@ public void deleteInstance() {
     System.out.println("\nDeleting Instance");
     // [START bigtable_delete_instance]
     try {
-      adminClient.deleteInstance(instanceId);
+      String name = "projects/" + projectId + "/instances/" + instanceId;
+      DeleteInstanceRequest request = DeleteInstanceRequest.newBuilder().setName(name).build();
+      adminClient.getBaseClient().deleteInstance(request);
       System.out.println("Instance deleted: " + instanceId);
     } catch (NotFoundException e) {
       System.err.println("Failed to delete non-existent instance: " + e.getMessage());
@@ -193,14 +222,23 @@ public void addCluster() {
     System.out.printf("%nAdding cluster: %s to instance: %s%n", CLUSTER, instanceId);
     // [START bigtable_create_cluster]
     try {
-      adminClient.createCluster(
-          CreateClusterRequest.of(instanceId, CLUSTER)
-              .setZone("us-central1-c")
+      String parent = "projects/" + projectId + "/instances/" + instanceId;
+      Cluster clusterObj =
+          Cluster.newBuilder()
+              .setLocation("projects/" + projectId + "/locations/us-central1-c")
               .setServeNodes(3)
-              .setStorageType(StorageType.SSD));
+              .setDefaultStorageType(StorageType.SSD)
+              .build();
+      CreateClusterRequest request =
+          CreateClusterRequest.newBuilder()
+              .setParent(parent)
+              .setClusterId(CLUSTER)
+              .setCluster(clusterObj)
+              .build();
+      adminClient.getBaseClient().createClusterAsync(request).get();
       System.out.printf("Cluster: %s created successfully%n", CLUSTER);
-    } catch (AlreadyExistsException e) {
-      System.err.println("Failed to add cluster, already exists: " + e.getMessage());
+    } catch (Exception e) {
+      System.err.println("Failed to add cluster: " + e.getMessage());
     }
     // [END bigtable_create_cluster]
   }
@@ -210,7 +248,9 @@ public void deleteCluster() {
     System.out.printf("%nDeleting cluster: %s from instance: %s%n", CLUSTER, instanceId);
     // [START bigtable_delete_cluster]
     try {
-      adminClient.deleteCluster(instanceId, CLUSTER);
+      String name = "projects/" + projectId + "/instances/" + instanceId + "/clusters/" + CLUSTER;
+      DeleteClusterRequest request = DeleteClusterRequest.newBuilder().setName(name).build();
+      adminClient.getBaseClient().deleteCluster(request);
       System.out.printf("Cluster: %s deleted successfully%n", CLUSTER);
     } catch (NotFoundException e) {
       System.err.println("Failed to delete a non-existent cluster: " + e.getMessage());