Exists method added in BigtableInstanceAdminClient

google-cloud-clients/google-cloud-bigtable-admin/src/main/java/com/google/cloud/bigtable/admin/v2/BigtableInstanceAdminClient.java

@@ -20,6 +20,7 @@
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutures;
 import com.google.api.gax.rpc.ApiExceptions;
+import com.google.api.gax.rpc.NotFoundException;
 import com.google.api.resourcenames.ResourceName;
 import com.google.bigtable.admin.v2.AppProfileName;
 import com.google.bigtable.admin.v2.ClusterName;
@@ -417,6 +418,68 @@ public Void apply(Empty input) {
     );
   }
 
+  /**
+   * Checks if the instance specified by the instanceId exists
+   *
+   * <p>Sample code:
+   *
+   * <pre>{@code
+   * if(client.exists("my-instance")) {
+   *   System.out.println("Instance exists");
+   * }
+   * }</pre>
+   */
+  public boolean exists(String instanceId) {
+    return ApiExceptions.callAndTranslateApiException(existsAsync(instanceId));
+  }
+
+  /**
+   * Asynchronously checks if the instance specified by the instanceId exists
+   *
+   * <p>Sample code:
+   *
+   * <pre>{@code
+   * ApiFuture<Boolean> found = client.existsAsync("my-instance");
+   *
+   * ApiFutures.addCallback(
+   *  found,
+   *  new ApiFutureCallback<Boolean>() {
+   *    public void onSuccess(Boolean found) {
+   *      if (found) {
+   *        System.out.println("Instance exists");
+   *      } else {
+   *        System.out.println("Instance not found");
+   *      }
+   *    }
+   *
+   *    public void onFailure(Throwable t) {
+   *      t.printStackTrace();
+   *    }
+   *  },
+   *  MoreExecutors.directExecutor()
+   * );
+   * }</pre>
+   */
+  public ApiFuture<Boolean> existsAsync(String instanceId) {
+    ApiFuture<Instance> protoFuture = getInstanceAsync(instanceId);
+
+    ApiFuture<Boolean> existsFuture = ApiFutures
+        .transform(protoFuture, new ApiFunction<Instance, Boolean>() {
+          @Override
+          public Boolean apply(Instance ignored) {
+            return true;
+          }
+        }, MoreExecutors.directExecutor());
+
+    return ApiFutures.catching(existsFuture, NotFoundException.class,
+        new ApiFunction<NotFoundException, Boolean>() {
+          @Override
+          public Boolean apply(NotFoundException ignored) {
+            return false;
+          }
+        }, MoreExecutors.directExecutor());
+  }
+
   /**
    * Creates a new cluster in the specified instance.
    *

google-cloud-clients/google-cloud-bigtable-admin/src/test/java/com/google/cloud/bigtable/admin/v2/BigtableInstanceAdminClientTest.java

@@ -23,12 +23,14 @@
 import com.google.api.gax.longrunning.OperationFuture;
 import com.google.api.gax.longrunning.OperationFutures;
 import com.google.api.gax.longrunning.OperationSnapshot;
+import com.google.api.gax.rpc.NotFoundException;
 import com.google.api.gax.rpc.OperationCallable;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.api.gax.rpc.testing.FakeOperationSnapshot;
 import com.google.bigtable.admin.v2.AppProfileName;
 import com.google.bigtable.admin.v2.ClusterName;
 import com.google.bigtable.admin.v2.CreateInstanceMetadata;
+import com.google.bigtable.admin.v2.GetInstanceRequest;
 import com.google.bigtable.admin.v2.InstanceName;
 import com.google.bigtable.admin.v2.LocationName;
 import com.google.bigtable.admin.v2.ProjectName;
@@ -57,12 +59,14 @@
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Empty;
 import com.google.protobuf.FieldMask;
+import io.grpc.Status;
 import io.grpc.Status.Code;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.Matchers;
 import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.mockito.invocation.InvocationOnMock;
@@ -842,4 +846,36 @@ public void testTestIamPermissions() {
     // Verify
     assertThat(actualResult).containsExactly("bigtable.tables.readRows");
   }
+
+  @Test
+  public void testExistsTrue() {
+    // Setup
+    com.google.bigtable.admin.v2.Instance expectedResponse = com.google.bigtable.admin.v2.Instance
+        .newBuilder().setName(INSTANCE_NAME.toString()).build();
+
+    Mockito.when(mockGetInstanceCallable.futureCall(Matchers.any(GetInstanceRequest.class)))
+        .thenReturn(ApiFutures.immediateFuture(expectedResponse));
+
+    // Execute
+    boolean found = adminClient.exists(INSTANCE_NAME.getInstance());
+
+    // Verify
+    assertThat(found).isTrue();
+  }
+
+  @Test
+  public void testExistsFalse() {
+    // Setup
+    NotFoundException exception =
+        new NotFoundException("fake-error", null, GrpcStatusCode.of(Status.Code.NOT_FOUND), false);
+
+    Mockito.when(mockGetInstanceCallable.futureCall(Matchers.any(GetInstanceRequest.class)))
+        .thenReturn(ApiFutures.immediateFailedFuture(exception));
+
+    // Execute
+    boolean found = adminClient.exists(INSTANCE_NAME.getInstance());
+
+    // Verify
+    assertThat(found).isFalse();
+  }
 }