fix according to PR comment

Author: ron-gal

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/NameUtil.java

@@ -106,6 +106,41 @@ public static String extractMaterializedViewIdFromMaterializedViewName(
     return matcher.group(3);
   }
 
+  /** A helper to convert fully qualified tableName andauthorizedViewName to a {@link TargetId} */
+  public static TargetId extractTargetId(
+      @Nonnull String tableName, @Nonnull String authorizedViewName) {
+    if (tableName.isEmpty() && authorizedViewName.isEmpty()) {
+      throw new IllegalArgumentException(
+          "Either table name, authorized view name or materialized view name must be specified. Table name: "
+              + tableName
+              + ", authorized view name: "
+              + authorizedViewName);
+    }
+    int names = 0;
+    if (!tableName.isEmpty()) {
+      ++names;
+    }
+    if (!authorizedViewName.isEmpty()) {
+      ++names;
+    }
+    if (names > 1) {
+      throw new IllegalArgumentException(
+          "Only one of table name and authorized view name can be specified at the same time. Table name: "
+              + tableName
+              + ", authorized view name: "
+              + authorizedViewName);
+    }
+
+    if (!tableName.isEmpty()) {
+      String tableId = extractTableIdFromTableName(tableName);
+      return TableId.of(tableId);
+    } else if (!authorizedViewName.isEmpty()) {
+      String tableId = extractTableIdFromAuthorizedViewName(authorizedViewName);
+      String authorizedViewId = extractAuthorizedViewIdFromAuthorizedViewName(authorizedViewName);
+      return AuthorizedViewId.of(tableId, authorizedViewId);
+    }
+  }
+
   /**
    * A helper to convert fully qualified tableName, authorizedViewName and materializedViewName to a
    * {@link TargetId}

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/models/BulkMutation.java

@@ -155,9 +155,8 @@ public static BulkMutation fromProto(@Nonnull MutateRowsRequest request) {
     String tableName = request.getTableName();
     String authorizedViewName = request.getAuthorizedViewName();
 
-    // Materialized Views are read only entities.
     BulkMutation bulkMutation =
-        BulkMutation.create(NameUtil.extractTargetId(tableName, authorizedViewName, ""));
+        BulkMutation.create(NameUtil.extractTargetId(tableName, authorizedViewName));
     bulkMutation.builder = request.toBuilder();
 
     return bulkMutation;

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/models/ConditionalRowMutation.java

@@ -177,10 +177,9 @@ public static ConditionalRowMutation fromProto(@Nonnull CheckAndMutateRowRequest
     String tableName = request.getTableName();
     String authorizedViewName = request.getAuthorizedViewName();
 
-    // Materialized Views are read only entities.
     ConditionalRowMutation rowMutation =
         ConditionalRowMutation.create(
-            NameUtil.extractTargetId(tableName, authorizedViewName, ""), request.getRowKey());
+            NameUtil.extractTargetId(tableName, authorizedViewName), request.getRowKey());
     rowMutation.builder = request.toBuilder();
 
     return rowMutation;

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/models/ReadModifyWriteRow.java

@@ -174,10 +174,9 @@ public static ReadModifyWriteRow fromProto(@Nonnull ReadModifyWriteRowRequest re
     String tableName = request.getTableName();
     String authorizedViewName = request.getAuthorizedViewName();
 
-    // Materialized Views are read only entities.
     ReadModifyWriteRow row =
         ReadModifyWriteRow.create(
-            NameUtil.extractTargetId(tableName, authorizedViewName, ""), request.getRowKey());
+            NameUtil.extractTargetId(tableName, authorizedViewName), request.getRowKey());
     row.builder = request.toBuilder();
 
     return row;

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/models/RowMutation.java

@@ -304,8 +304,7 @@ public static RowMutation fromProto(@Nonnull MutateRowRequest request) {
     String authorizedViewName = request.getAuthorizedViewName();
 
     return RowMutation.create(
-        // Materialized Views are read only entities.
-        NameUtil.extractTargetId(tableName, authorizedViewName, ""),
+        NameUtil.extractTargetId(tableName, authorizedViewName),
         request.getRowKey(),
         Mutation.fromProto(request.getMutationsList()));
   }

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/admin/v2/internal/NameUtilTest.java

@@ -103,7 +103,31 @@ public void extractTableNameFromAuthorizedViewNameTest() {
   }
 
   @Test
-  public void testExtractTargetId() {
+  public void testExtractTargetId2() {
+    String testTableName = "projects/my-project/instances/my-instance/tables/my-table";
+    String testAuthorizedViewName =
+        "projects/my-project/instances/my-instance/tables/my-table/authorizedViews/my-authorized-view";
+    assertThat(
+            com.google.cloud.bigtable.data.v2.internal.NameUtil.extractTargetId(
+                testTableName, "", ""))
+        .isEqualTo(TableId.of("my-table"));
+    assertThat(
+            com.google.cloud.bigtable.data.v2.internal.NameUtil.extractTargetId(
+                "", testAuthorizedViewName, ""))
+        .isEqualTo(AuthorizedViewId.of("my-table", "my-authorized-view"));
+
+    // No name is provided
+    exception.expect(IllegalArgumentException.class);
+    com.google.cloud.bigtable.data.v2.internal.NameUtil.extractTargetId("", "");
+
+    // Multiple names are provided
+    exception.expect(IllegalArgumentException.class);
+    com.google.cloud.bigtable.data.v2.internal.NameUtil.extractTargetId(
+        testTableName, testAuthorizedViewName);
+  }
+
+  @Test
+  public void testExtractTargetId3() {
     String testTableName = "projects/my-project/instances/my-instance/tables/my-table";
     String testAuthorizedViewName =
         "projects/my-project/instances/my-instance/tables/my-table/authorizedViews/my-authorized-view";